JPH08316702A - High-frequency filter and impedance transformer - Google Patents

Abstract

PURPOSE: To obtain an excellent broad band characteristic by specifying the reflection loss or the insertion loss for each of plural frequencies in a pass band to a desired value and setting the shape and the interval of a resonator so as to suppress the increase in reflection at the end of the pass band over a broad band. CONSTITUTION: A band pass filter with an ideal Chebychev characteristic comprising lumped constant elements and an equivalent circuit of a distributed constant type determined in response to the physical shape are compared at the center frequency of the pass band of the filter to obtain the separation width and length between resonators 30, each resonator being design parameters. Then the filter character is calculated by the equivalent circuit of the distributed constant type by specifying an insertion loss or a reflection loss at each of plural frequencies to be a prescribed value, the parameters of the equivalent circuit is optimized so that the reflection loss or the insertion loss for each frequency to be a specified value thereby obtaining the interval of resonators between resonators 30, a width and a length of each resonator. Thus, the coupling among the resonators 30 is weak at frequency other than a frequency at a prescribed pass band, power of an incident wave to an input line 6 is almost reflected and only power for the prescribed frequency is outputted to an output line 70.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is mainly applied to VHF band,
The present invention relates to widening the frequency range of high-frequency filters and impedance transformers used in the UHF band, microwave band, and millimeter wave band.

[0002]

2. Description of the Related Art FIGS. 34-35 are published by S. Herbert, "Microstr.
ip Interdigital Filter Design, ”Microwave Journal
, pp.187-188, Nov.1990, or JAGMalherbe,
“Microwave Transmission Line Filters”, ARTECH H
OUSE, INC, pp.111-130, 1979. It is a figure which shows the design procedure of the conventional high frequency filter, FIG. 34 is a design flow, FIG. 35 is a circuit of a prototype low pass filter, FIG. Is an equivalent circuit of a bandpass filter.
In FIG. 35, Ci '(i = 1,3) and Li' (i = 2,4) are elements of the original low-pass filter, G0 'is a source impedance, G5' is a load impedance, and gi (i = 0,4). 1, ...,
5) is a coefficient determined by the transfer function of the filter.
Further, in FIG. 36, Li (i = 1, ..., 4) is a parallel inductance, Ji, i + 1 (i, = 1,2,3) is a J inverter, and δ0.
And δ5 are impedance transformation ratios. Li and J
i and i + 1 are represented by the equivalent circuit of the distributed constant line shown in FIGS. 36B and 36C in the vicinity of the frequency where θ = π / 2.

Next, the design procedure will be described. First, the element value of the original low-pass filter is determined from the desired passband width, ripple in the passband, the number of resonator stages, and the coefficient of the Chebyshev series used as the transfer function.
Next, frequency conversion is performed on the original low-pass filter, and further, a J inverter is introduced to convert it into the equivalent circuit of the band-pass filter shown in FIG. At this time J
The inverter and parallel inductance are shown in Fig. 36 (b),
As shown in (c), it is replaced with a distributed constant type equivalent circuit using a tip short-circuited stub with an electrical length of approximately in the vicinity of the center frequency of the filter. A conventional interdigital bandpass filter is designed by using this distributed constant type equivalent circuit.

The high frequency filter is generally composed of a resonator of a distributed constant line, and the frequency characteristic can be calculated relatively accurately by the equivalent circuit of FIG. The reflection characteristic of the conventional high-frequency filter shown in FIG. 36 has a large error due to the approximation of FIGS. 36 (b) and 36 (c) at frequencies away from the center frequency. As shown, the reflection loss increases at the pass band edge.

38 to 40 show RECollin, "F
soundations for Microwave Engineering ”, McGraw-Hi
ll, Inc, pp.639-642, 1979. or another conventional high-frequency filter design procedure shown in Japanese Patent Laid-Open No. 6-216608, FIG. 38 is a design flow, and FIG. 39 is a prototype low-frequency filter. The circuit of the band pass filter, and FIGS. 40 and 41 are equivalent circuits of the waveguide band pass filter. In FIG. 39, Ci '(i = 1,3, ..., 11) and Li', (i = 2,4, ..., 10)
Is the element of the original low-pass filter, G0 'is the source impedance, G5' is the load impedance, gi, (i = 0,1,
..., 12) are the coefficients determined by the transfer function of the filter. Further, in FIG. 40 (a), Li (i = 1,2, ..., 1
1) is a series inductance, Ci (i = 1,2, ..., 11) is a series capacitance, and Ki, i + 1 (i, = 1,2,3) is a K inverter. In the vicinity of the frequency where θ = π, Ki, j
Is represented by the parallel susceptance Bi, j shown in FIG. Bi, j is realized, for example, by an inductive iris. Further, the series resonant circuit composed of Li and Ci is represented by a waveguide circuit having an electrical length of θi.

Next, the design procedure will be described. First, the element value of the original low-pass filter is determined from the desired pass band width, the ripple in the pass band, the number of resonator stages, and the coefficient when the Chebyshev function used as the transfer function is expanded in series. Next, frequency conversion is performed on the original low-pass filter, and a K inverter is further introduced to convert the equivalent circuit of the band-pass filter shown in FIG. At this time, near the center frequency of the filter,
As shown in FIGS. 40 (a) and 40 (b), Ki, j is approximated by a parallel susceptance Bi, j, and a series resonant circuit composed of Li and Ci is approximated by a waveguide circuit having an electrical length θi. The waveband type bandpass filter is represented by the distributed constant type equivalent circuit shown in FIG. The conventional waveguide type bandpass filter is designed using this distributed constant type equivalent circuit.

The reflection characteristic of the conventional waveguide type band pass filter shown in FIG. 41 has an error due to the approximation of FIGS. 40 (b) and 40 (c) at a frequency away from the center frequency as in the case of the filter shown in FIG. Since it becomes large, the reflection loss becomes large at the end of the pass band as shown by the solid line in FIG. 42 especially when the pass band is wide. In particular, the waveguide bandpass filter has a large dispersion of the wavelength in the waveguide with respect to the frequency change, and the ratio of the change in the electrical length with respect to the frequency change is large. The deterioration of the characteristics becomes remarkable.

Further, FIGS. 43 and 44 show RECollin,
“Foundations for Microwave Engineering”, McGra
43 is a diagram showing a design procedure of the conventional impedance transformer shown in w-Hill, Inc, pp.343-360, 1979.
Is a design flow, and FIG. 44 is an equivalent circuit. In FIG. 44, Zi (i = 1,2, ..., 4) is the characteristic impedance of the distributed constant line, Z0 is the characteristic impedance of the input line, ZL 'is the characteristic impedance of the output line, and θ is the electrical length of the distributed constant line. is there.

Next, the design procedure will be described. First, the number of stages of the impedance transformer is specified, and the equation of the reflection coefficient of the impedance transformer is obtained using the equivalent circuit of FIG. If the electric lengths of the distributed constant lines are set equal and the reflection at the connection surface between the adjacent distributed constant lines is sufficiently small, the reflection coefficient is expanded to a polynomial using a trigonometric function. At this time, the reflection coefficient in the pass band is accurately expressed using the Chebyshev function if the pass band width and the number and magnitude of ripples in the pass band are specified. The Chebyshev function can be expanded by a trigonometric function, and the characteristic impedance of each distributed constant line of the impedance transformer can be obtained by comparing this with the polynomial of the reflection coefficient obtained from the equivalent circuit of FIG. At this time, the line length of the distributed constant line is set so that the electrical length θ becomes π / 2 at the center frequency.

In an actual impedance transformer,
Since a physical step such as the conductor width occurs at the connection between adjacent distributed constant lines with different characteristic impedances,
This discontinuity causes susceptance. This susceptance has the function of changing the electrical length of the distributed constant line equivalently. In normal design, the total electrical length including this change in electrical length is π / 2 at the design center frequency. Determine the physical length of. However, since the electrical length due to this susceptance differs from the electrical length of the distributed constant line in the rate of frequency change, the reflection coefficient of an impedance transformer with an equivalent circuit including discontinuous susceptance is calculated from the Chebyshev function at frequencies away from the center frequency. It shifts. Therefore, the reflection characteristic of the conventional impedance transformer according to FIG. 44 has a large reflection loss at the pass band edge as shown by the solid line in FIG. 45 at frequencies away from the center frequency as in the case of the filters of FIGS. 36 and 41. Become.

[0011]

Since the conventional high-frequency filter and impedance transformer are configured as described above, the reflection characteristic by the equivalent circuit corresponding to the physical shape is transmitted at the frequency away from the designed center frequency. There is a problem in that the ideal reflection characteristic obtained from the function deteriorates, and thus a characteristic of small reflection cannot be obtained over a wide band.

The present invention has been made to solve the above problems, and a design method capable of reducing reflection over a wide band, and a high frequency filter and impedance transformer having a small reflection over a wide band by using this design method. Aim to get.

[0013]

A high frequency filter according to a first aspect of the present invention includes a plurality of transmission line type resonators, inter-resonator coupling means for mutually coupling the resonators, and the resonator and the input / output. In a high-frequency filter provided with an input / output coupling means for coupling a line to each other, the resonator length of the resonator, the dimension of the inter-resonator coupling means, and the number of parameters determining the dimension of the input / output coupling means. The frequencies are selected by the above number, and the resonator length of the resonator, the dimension of the inter-resonator coupling means, and the upper frequency are selected so that the pass characteristic or the reflection characteristic of the high frequency filter approaches a desired value at the selected frequency. The size of the input / output coupling means is determined.

In the high frequency filter according to the second invention, a plurality of transmission line type resonators, inter-resonator coupling means for mutually coupling the resonators, and the resonator and the input / output line are mutually connected. In a high frequency filter having an input / output coupling means for coupling to a plurality of gradient zero points, a plurality of gradient zero points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter. Is defined as the reflection zero frequency or the reflection maximum frequency, and the resonator length of the resonator and the inter-resonator coupling means are set so that the reflection becomes minimum or maximum at the reflection zero frequency or the reflection maximum frequency. Size,
The dimensions of the input / output coupling means are determined.

In the high frequency filter according to the third invention, a plurality of transmission line type resonators, inter-resonator coupling means for mutually coupling the resonators, and the resonator and the input / output line are mutually connected. A high-frequency filter having an input / output coupling means for coupling to a plurality of zero points of the Chebyshev function as a function of the frequency of the radio wave in the resonator within the pass band of the high-frequency filter, corresponding to the plurality of zero points. Is defined as the reflection zero frequency, and the resonator length of the resonator, the dimensions of the inter-resonator coupling means, and the dimensions of the input / output coupling means are determined so that the reflection is minimized at the reflection zero frequency. It was done.

In the high frequency filter according to the fourth aspect of the present invention, a plurality of transmission line type resonators, inter-resonator coupling means for mutually coupling the resonators, and the resonator and the input / output line are mutually connected. A high-frequency filter having an input / output coupling means for coupling to a plurality of zero points of the Chebyshev function as a function of the frequency of the radio wave in the resonator within the pass band of the high-frequency filter, corresponding to the plurality of zero points. Is defined as the reflection zero frequency, and the resonator length of the resonator, the dimensions of the inter-resonator coupling means, and the dimensions of the input / output coupling means are determined so that the reflection is minimized at the reflection zero frequency. Then, of the reflection characteristics of the high frequency filter obtained by using the above dimensions, select a frequency with a larger reflection than the characteristics of the ideal Chebyshev type filter,
The resonator length of the resonator, the dimensions of the inter-resonator coupling means, and the dimensions of the input / output coupling means are determined so that the reflection is equal to or less than a predetermined magnitude at the high reflection frequency and the zero reflection frequency. It was done.

In the high frequency filter according to the fifth aspect of the invention, a plurality of transmission line type resonators, inter-resonator coupling means for mutually coupling the resonators, and the resonator and the input / output line are mutually connected. In the high-frequency filter having an input / output coupling means for coupling to, a plurality of maximum points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high-frequency filter, and the plurality of maximum points are set. Is defined as the reflection maximum frequency, and the resonator length of the resonator, the dimensions of the inter-resonator coupling means, and the input-output coupling are set so that the reflection has a predetermined maximum value at the reflection maximum frequency. The dimensions of the means are determined.

In the high frequency filter according to the sixth aspect of the invention, a plurality of transmission line type resonators, inter-resonator coupling means for mutually coupling the resonators, and the resonator and the input / output line are mutually connected. In the high-frequency filter having an input / output coupling means for coupling to, a plurality of maximum points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high-frequency filter, and the plurality of maximum points are set. Is defined as the reflection maximum frequency, and the resonator length of the resonator, the dimensions of the inter-resonator coupling means, and the input-output coupling are set so that the reflection has a predetermined maximum value at the reflection maximum frequency. Of the reflection characteristics of the high-frequency filter obtained by determining the dimensions of the means, using the dimensions,
A frequency with a large reflection is selected based on the characteristics of an ideal Chebyshev filter, and the resonator length of the resonator and the distance between the resonators are set so that the reflection has a predetermined value or less at the large reflection frequency and the reflection maximum frequency. The dimensions of the coupling means and the dimensions of the input / output coupling means are determined.

A high frequency filter according to a seventh aspect of the present invention is a high frequency filter including a plurality of cavity resonators each comprising a waveguide and coupling means for coupling the cavity resonators and a susceptance element as an input / output coupling means. In the wave tube type high frequency filter, a plurality of zero points of the Chebyshev function as a function of the in-tube wavelength of the waveguide are set in the pass band of the waveguide type high frequency filter, and the in-tube wavelengths of the plurality of zero points are set. The corresponding frequency is defined as the reflection zero frequency, and the resonator length of the resonator, the susceptance element value, and the dimension of the susceptance element are determined so that the reflection is minimized at the reflection zero frequency.

A high frequency filter according to an eighth aspect of the present invention is a high frequency filter including a plurality of cavity resonators each comprising a waveguide and coupling means for coupling the cavity resonators and a susceptance element as an input / output coupling means. In the wave tube type high frequency filter, a plurality of zero points of the Chebyshev function as a function of the in-tube wavelength of the waveguide are set in the pass band of the waveguide type high frequency filter, and the in-tube wavelengths of the plurality of zero points are set. The corresponding frequency is defined as the reflection zero frequency, and the resonator length of the resonator, the susceptance element value, and the dimensions of the susceptance element are determined so that the reflection is minimized at the reflection zero frequency, and the above dimensions are used. Of the reflection characteristics of the above-mentioned waveguide type filter obtained as a result, select a frequency with larger reflection than the characteristic of the ideal Chebyshev type filter,
The resonator length of the resonator, the value of the susceptance element, and the dimensions of the susceptance element are determined so that the reflection becomes equal to or less than a predetermined magnitude at the high reflection frequency and the reflection zero frequency.

A high frequency filter according to a ninth aspect of the present invention is a high frequency filter including a plurality of cavity resonators each comprising a waveguide and coupling means for coupling the cavity resonators and a susceptance element as an input / output coupling means. In a wave tube type high frequency filter, a plurality of maximum points of the Chebyshev function as a function of the in-tube wavelength of the waveguide are set in the pass band of the waveguide type high frequency filter, and the maximum points of the plurality of maximum points are in the tube. The frequency corresponding to the wavelength is defined as the reflection maximum frequency, and the resonator length of the resonator, the susceptance element value, and the dimension of the susceptance element are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency. It is a thing.

A high frequency filter according to a tenth aspect of the present invention is a conductor provided with a plurality of cavity resonators each comprising a waveguide and coupling means for coupling the cavity resonators and a susceptance element as an input / output coupling means. In a wave tube type high frequency filter, a plurality of maximum points of the Chebyshev function as a function of the in-tube wavelength of the waveguide are set in the pass band of the waveguide type high frequency filter, and the maximum points of the plurality of maximum points are in the tube. The frequency corresponding to the wavelength is defined as the reflection maximum frequency, and the resonator length of the resonator, the susceptance element value, and the dimension of the susceptance element are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency. , Of the reflection characteristics of the waveguide filter obtained using the above dimensions,
A frequency with a large reflection is selected based on the characteristics of an ideal Chebyshev filter, and the resonator length of the resonator and the susceptance element value are set so that the reflection has a predetermined value or less at the large reflection frequency and the reflection maximum frequency. ,
And the dimensions of the susceptance element.

A high frequency filter according to the eleventh aspect of the present invention is the high frequency filter according to any one of claims 7 to 10, wherein the susceptance element is an inductive iris or an inductive post.

A high frequency filter according to the twelfth invention is the high frequency filter according to any one of claims 7 to 11, wherein the number of resonators is N and the equivalent circuit element value at the center frequency of the filter is determined. When the susceptance value of the i-th susceptance element is B0i, the susceptance value Bi of the i-th susceptance element is set in the range given by the following equation. 1 <Bi / B0i <1.2 (1 ≦ i ≦ 0.2N, N ≦ i ≦ N + 1) 0.8 <Bi / B0i <1 (0.2N <i ≦ 0.4, 0.8N ≦ i < N) 0.9 <Bi / B0i ≦ 1 (0.4N <i <0.8N)

The impedance transformer according to the thirteenth aspect of the present invention is a plurality of transmission lines of about 1/4 wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line. In the impedance transformer provided with, select the line length of the transmission line, and the frequency of the number of parameters or more to determine the characteristic impedance, the pass characteristics or reflection characteristics of the impedance transformer at the selected frequency. The line length of the above-mentioned transmission line so as to approach the desired value,
And the characteristic impedance is determined.

The impedance transformer according to the fourteenth aspect of the present invention is a plurality of transmission lines of about ¼ wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line. In an impedance transformer having and, a plurality of slope zero points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set in the pass band of the impedance transformer,
The frequency corresponding to the plurality of zero slopes is defined as the reflection zero frequency or the reflection maximum frequency, and the line length of the transmission line is set so that the reflection has a minimum value or a predetermined maximum value at the reflection zero frequency or the reflection maximum frequency. ,
And the characteristic impedance is determined.

The impedance transformer according to the fifteenth aspect of the present invention is a plurality of transmission lines of about ¼ wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line. In an impedance transformer including and, a plurality of zero points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set in the pass band of the impedance transformer, and the frequencies corresponding to the plurality of zero points are reflected to zero. It is defined as a frequency, and the line length and the characteristic impedance of the transmission line are determined so that the reflection is minimized at the reflection zero frequency.

The impedance transformer according to the sixteenth aspect of the invention is a plurality of transmission lines of about 1/4 wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line. In an impedance transformer including and, a plurality of zero points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set in the pass band of the impedance transformer, and the frequencies corresponding to the plurality of zero points are reflected to zero. It is specified as a frequency, and the line length of the transmission line and the characteristic impedance are determined so that the reflection is minimized at the reflection zero frequency, and the ideal one of the reflection characteristics of the impedance transformer obtained by using the dimensions is ideal. Select a frequency with a large reflection from the characteristics of the Chebyshev transformer, and Reflected at the reflection zero frequency is obtained by determining the line length, and the characteristic impedance of the transmission line so as not to exceed a predetermined magnitude.

The impedance transformer according to the seventeenth aspect of the present invention is a plurality of transmission lines of about 1/4 wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line. In an impedance transformer with and, by setting a plurality of local maximum points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line in the pass band of the impedance transformer, the frequency corresponding to the plurality of local maximum points. It is defined as the reflection maximum frequency, and the line length and the characteristic impedance of the transmission line are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency.

The impedance transformer according to the eighteenth aspect of the present invention is a plurality of transmission lines of about ¼ wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line. In an impedance transformer with and, by setting a plurality of local maximum points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line in the pass band of the impedance transformer, the frequency corresponding to the plurality of local maximum points. It is defined as the reflection maximum frequency, the line length of the transmission line and the characteristic impedance are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency, and the reflection characteristic of the impedance transformer obtained by using the above dimensions is obtained. Of the above, select a frequency with a larger reflection than the characteristics of an ideal Chebyshev transformer, It reflected in frequency and the reflection maximum frequency is obtained by determining the line length, and the characteristic impedance of the transmission line so as not to exceed a predetermined magnitude.

The impedance transformer according to the nineteenth aspect of the present invention comprises a plurality of substantially quarter wavelength waveguides and steps in the height direction or the width direction between the waveguides and the waveguides. In a waveguide-type impedance transformer with steps in the height or width direction between it and the output waveguide, in a passband of the impedance transformer as a function of the waveguide wavelength in the waveguide. A plurality of Chebyshev function zeros are set, a frequency corresponding to the in-tube wavelengths of the plurality of zeros is defined as a reflection zero frequency, and the axial length of the waveguide is set so that reflection is minimized at the reflection zero frequency, and , The height or width is determined.

An impedance transformer according to the twentieth aspect of the present invention is a plurality of substantially quarter wavelength waveguides and steps in the height direction or width direction between the waveguides, and the waveguides. In a waveguide-type impedance transformer with steps in the height or width direction between it and the output waveguide, in a passband of the impedance transformer as a function of the waveguide wavelength in the waveguide. A plurality of zero points of the Chebyshev function are set, a frequency corresponding to the in-tube wavelength of the plurality of zero points is defined as a reflection zero frequency, and the axial length of the waveguide is set so that the reflection has a minimum at the reflection zero frequency, and , The height or width is determined, and of the reflection characteristics of the waveguide type impedance transformer obtained by using the above dimensions, the frequency with larger reflection is selected than the characteristic of the ideal Chebyshev transformer. , The axial length of the waveguide as reflected in large frequency and the reflection zero frequency of the reflection is less than or equal to a predetermined size, and is obtained by determining the height or width.

The impedance transformer according to the twenty-first aspect of the present invention comprises a plurality of substantially quarter wavelength waveguides and steps in the height direction or the width direction between the waveguides and the waveguides. In a waveguide-type impedance transformer with steps in the height or width direction between it and the output waveguide, in a passband of the impedance transformer as a function of the waveguide wavelength in the waveguide. A plurality of maximum points of the Chebyshev function are set, a frequency corresponding to the in-tube wavelength of the plurality of maximum points is defined as a reflection maximum frequency, and the waveguide is set so that the reflection has a predetermined maximum value at the reflection maximum frequency. The axis length and height or width of the are determined.

The impedance transformer according to the twenty-second aspect of the present invention comprises a plurality of substantially quarter-wavelength waveguides and steps in the height direction or width direction between the waveguides, and the waveguides. In a waveguide-type impedance transformer with steps in the height or width direction between it and the output waveguide, in a passband of the impedance transformer as a function of the waveguide wavelength in the waveguide. A plurality of maximum points of the Chebyshev function are set, a frequency corresponding to the in-tube wavelength of the plurality of maximum points is defined as a reflection maximum frequency, and the waveguide is set so that the reflection has a predetermined maximum value at the reflection maximum frequency. Of the reflection characteristics of the waveguide type impedance transformer obtained by using the above-mentioned dimensions by determining the axial length and height or width of the Select Kina frequency, the axial length of the waveguide as reflected in large frequency and the reflection maximum frequency of the reflection is less than or equal to a predetermined size, and,
It determines the height or width.

[0035]

According to the first aspect of the present invention, the frequency is selected by at least the number of parameters for determining the resonator length of the resonator as the design parameter, the dimension of the inter-resonator coupling means, and the dimension of the input / output coupling means. , The resonator length of the resonator, the dimensions of the inter-resonator coupling means, and the dimensions of the input / output coupling means are determined so that the pass characteristic or the reflection characteristic of the high frequency filter approaches a desired value at the selected frequency. Therefore, not only the center frequency but also a plurality of frequencies within the range of the selected frequency is used to set the conditional expression of the number of parameters or more, and even when the pass band is wide by the optimization method, the desired reflection characteristic The values of the design parameters obtained can be determined.

In the second invention, a plurality of slope zero points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter, and frequencies corresponding to the plurality of slope zero points are reflected. It is specified as zero frequency or maximum reflection frequency, and the resonator length, dimensions of interresonator coupling means, and input-output coupling are designed so that the reflection becomes minimum or maximum at the reflection zero frequency or reflection maximum frequency. Since the size of the means is determined, the increase of reflection at the pass band edge and the deviation of the reflection zero frequency are small, and the desired reflection characteristic close to the ideal characteristic by the Chebyshev function at all frequencies in the above pass band by the optimization method etc. The values of the above design parameters obtained can be determined.

In the third invention, a plurality of zero points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter, and frequencies corresponding to the plurality of zero points are reflected zero frequencies. Since the resonator length, the dimensions of the coupling means between resonators, and the dimensions of the coupling means between input and output are determined as design parameters so that the reflection becomes a minimum at the reflection zero frequency, the minimum frequency By the optimization method used, the values of the above-mentioned design parameters for obtaining desired reflection characteristics close to the ideal characteristics by the Chebyshev function can be determined at all frequencies within the pass band.

In the fourth invention, a plurality of zero points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter, and frequencies corresponding to the plurality of zero points are set as reflection zero frequencies. The resonator length, the dimensions of the inter-resonator coupling means, and the dimensions of the input / output coupling means are determined as design parameters so that the reflection has a minimum value at the reflection zero frequency, and the obtained values are obtained using the above dimensions. Of the reflection characteristics of the high-frequency filter, a frequency having a larger reflection than that of an ideal Chebyshev-type filter is selected, and the resonance is set so that the reflection has a predetermined value or less at the large reflection frequency and the reflection zero frequency. Since the resonator length of the resonator, the dimensions of the inter-resonator coupling means, and the dimensions of the input / output coupling means are determined, optimization is performed a plurality of times, The optimization method or the like using a frequency of the small limit can determine the value of the design parameters obtained of the desired reflection characteristics very close to the ideal characteristics of Chebyshev function at all frequencies within the passband.

In the fifth invention, a plurality of maximum points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter, and the frequencies corresponding to the plurality of maximum points are reflected maximum. Since the resonator length, interresonator coupling means dimensions, and input / output coupling means dimensions are determined as design parameters so that the reflection has a predetermined maximum value at the reflection maximum frequency, the minimum It is possible to determine the value of the design parameter that gives a desired reflection characteristic close to the ideal characteristic by the Chebyshev function at all frequencies in the pass band by an optimization method using a limit frequency.

In the sixth invention, a plurality of maximum points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter, and the frequencies corresponding to the plurality of maximum points are reflected maximum. The resonator length, the dimensions of the inter-resonator coupling means, and the dimensions of the input-output coupling means are determined as design parameters so that the reflection has a predetermined maximum value at the reflection maximum frequency. Among the reflection characteristics of the high-frequency filter obtained by using, a frequency with larger reflection is selected than the characteristic of an ideal Chebyshev-type filter, and the reflection becomes less than a predetermined magnitude at the frequency of large reflection and the reflection maximum frequency. Since the resonator length of the resonator, the dimension of the coupling means between the resonators, and the dimension of the coupling means between the input and output are determined as described above, Optimization has been performed, and the values of the above-mentioned design parameters that can obtain the desired reflection characteristics that are very close to the ideal characteristics by the Chebyshev function at all frequencies within the passband can be determined by the optimization method using the minimum frequency. .

In the seventh invention, a plurality of zero points of the Chebyshev function as a function of the waveguide wavelength of the waveguide are set in the pass band of the waveguide filter, and the zero points correspond to the waveguide wavelengths of the zero points. Is defined as the reflection zero frequency, and the resonator length, susceptance element value, and susceptance element dimensions as design parameters are determined so that the reflection is minimized at the reflection zero frequency. Even for a particularly large waveguide filter, the above-mentioned design parameters by which the desired reflection characteristics close to the ideal characteristics by the Chebyshev function can be obtained at all frequencies within the pass band by the optimization method using the minimum frequency etc. The value of can be determined.

In the eighth invention, a plurality of zero points of the Chebyshev function as a function of the in-tube wavelength of the waveguide are set in the pass band of the waveguide filter to correspond to the in-tube wavelengths of the plurality of zero points. Is defined as the reflection zero frequency, and the resonator length, susceptance element value, and susceptance element dimensions as design parameters are determined so that the reflection is minimized at the reflection zero frequency. Of the reflection characteristics of the waveguide type filter, a frequency having a larger reflection than that of an ideal Chebyshev type filter is selected so that the reflection has a predetermined magnitude or less at the frequency of the large reflection and the reflection zero frequency. Since the resonator length of the resonator, the value of the susceptance element, and the dimension of the susceptance element have been determined, it is possible to optimize multiple times. Therefore, even for a waveguide filter with a large change in the frequency of the electrical length, it is very close to the ideal characteristic by the Chebyshev function at all frequencies within the above passband by the optimization method using the minimum frequency. It is possible to determine the values of the above-mentioned design parameters that give the desired reflection characteristics.

In the ninth invention, a plurality of maximum points of the Chebyshev function as a function of the guide wavelength of the waveguide are set in the pass band of the waveguide filter, and the guide wavelengths of the plurality of maximum points are set. The frequency corresponding to is defined as the reflection maximum frequency, and the resonator length as a design parameter so that the reflection has a predetermined maximum value at the reflection maximum frequency,
Since the value of the susceptance element and the dimensions of the susceptance element are determined, even in the case of a waveguide filter with a large change in the electrical length with respect to frequency, it is possible to optimize all values in the pass band by the optimization method using the minimum frequency. It is possible to determine the values of the above-mentioned design parameters that give desired reflection characteristics close to the ideal characteristics by the Chebyshev function at the frequency of.

In the tenth invention, a plurality of maximum points of the Chebyshev function as a function of the guide wavelength of the waveguide are set in the pass band of the waveguide filter, and the guide wavelengths of the plurality of maximum points are set. The frequency corresponding to the above is defined as the reflection maximum frequency, and the resonator length, the susceptance element value, and the dimension of the susceptance element as design parameters are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency. Among the reflection characteristics of the above-mentioned waveguide type filter obtained by using, a frequency having a larger reflection than that of an ideal Chebyshev type filter is selected, and the reflection has a predetermined magnitude at the large reflection frequency and the maximum reflection frequency. The resonator length of the resonator as follows,
Since the value of the susceptance element and the dimension of the susceptance element are determined, the optimization is performed multiple times, and even for a waveguide filter in which the frequency change of the electrical length is particularly large, the optimum using the minimum frequency is used. It is possible to determine the values of the above-mentioned design parameters by which the desired reflection characteristics very close to the ideal characteristics by the Chebyshev function are obtained at all frequencies within the pass band by means of the optimization method.

In the eleventh invention, since the inductive iris or the inductive post is used as the susceptance element in any of the seventh to tenth inventions, the iris width of the inductive iris or the number of the inductive posts is used. The desired susceptance value can be easily obtained by adjusting the diameter, the diameter, or the interval, and the excellent susceptance value can be obtained.

In the twelfth invention, the number of resonators in any one of the seventh to eleventh inventions is N, and the susceptance value of the i-th susceptance element determined from the equivalent circuit element value at the center frequency of the filter. B0i, the susceptance value Bi of the i-th susceptance element
1 <Bi / B0i <1.2 (1 ≦ i ≦ 0.2N, N ≦ i ≦ N + 1) 0.8 <Bi / B0i <1 (0.2N <i ≦ 0.4, 0.8N ≦ Since i <N) 0.9 <Bi / B0i ≦ 1 (0.4N <i <0.8N), the Chebyshev function is set at all frequencies within the pass band even if the pass band is wide. A desired reflection characteristic close to the ideal characteristic can be obtained.

In the thirteenth invention, the line length of the transmission line as a design parameter and the number of frequencies equal to or more than the number of parameters for determining the characteristic impedance are selected,
Since the line length of the transmission line and the characteristic impedance are determined so that the pass characteristic or the reflection characteristic of the impedance transformer approaches the desired value at the selected frequency, not only the center frequency but also within the selected frequency range. Conditional expressions equal to or more than the number of parameters are set by using a plurality of frequencies, and the value of the design parameter with which desired reflection characteristics can be obtained can be determined by an optimization method even when the pass band is wide.

In the fourteenth aspect, a plurality of slope zero points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set in the pass band of the impedance transformer, and frequencies corresponding to the plurality of slope zero points are set. It is defined as the reflection zero frequency or the reflection maximum frequency, and the line length of the transmission line as a design parameter and the characteristic impedance are determined so that the reflection has a minimum value or a predetermined maximum value at the reflection zero frequency or the reflection maximum frequency. Therefore, it is possible to determine the value of the above-mentioned design parameter by which the desired reflection characteristic close to the ideal characteristic by the Chebyshev function is obtained at all frequencies within the pass band by an optimization method or the like.

In the fifteenth aspect, a plurality of zero points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set in the pass band of the impedance transformer, and the frequencies corresponding to the plurality of zero points are reflected to zero. Since the line length of the transmission line as a design parameter and the characteristic impedance are determined so that the reflection is minimized at the reflection zero frequency, the pass band is determined by the optimization method using the minimum frequency. It is possible to determine the values of the above-mentioned design parameters at which desired reflection characteristics close to the ideal characteristics by the Chebyshev function are obtained at all frequencies within.

In the sixteenth invention, a plurality of zero points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set in the pass band of the impedance transformer, and the frequencies corresponding to the plurality of zero points are reflected to zero. Defined as the frequency, the line length of the transmission line as a design parameter so as to minimize the reflection at the reflection zero frequency, and the characteristic impedance is determined, and among the reflection characteristics of the impedance transformer obtained by using the above dimensions. , Select a frequency with a large reflection from the characteristics of an ideal Chebyshev transformer, and set the axial length and height of the transmission line so that the reflection becomes less than a predetermined value at the large reflection frequency and the zero reflection frequency. Since it was decided, the optimization is performed multiple times, and by using the optimization method using the minimum frequency, etc. The value of the design parameters obtained of the desired reflection characteristics very close to the ideal characteristics of Chebyshev function at the frequency of Te can be determined.

In the seventeenth invention, a plurality of local maximum points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set in the pass band of the impedance transformer.
The frequency corresponding to the plurality of maximum points is defined as the reflection maximum frequency, and the line length of the transmission line as a design parameter and the characteristic impedance are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency. It is possible to determine the value of the above-mentioned design parameter that obtains a desired reflection characteristic close to an ideal characteristic by the Chebyshev function at all frequencies within the pass band by an optimization method using the minimum frequency.

In the eighteenth invention, a plurality of local maximum points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set in the pass band of the impedance transformer.
The frequency corresponding to the plurality of maximum points is defined as the reflection maximum frequency, the line length of the transmission line as a design parameter is determined so that the reflection has a predetermined maximum value at the reflection maximum frequency, and the characteristic impedance is determined. Of the reflection characteristics of the impedance transformer obtained by using dimensions, a frequency with a larger reflection is selected than the characteristic of an ideal Chebyshev transformer, and the reflection has a predetermined magnitude at the large reflection frequency and the maximum reflection frequency. Since the line length and characteristic impedance of the transmission line were determined as shown below, it was optimized multiple times, and the Chebyshev at all frequencies within the pass band was optimized by the optimization method using the minimum frequency. Determine the values of the above design parameters that give the desired reflection characteristics that are very close to the ideal characteristics by the function. Kill.

In the nineteenth aspect, a plurality of zero points of the Chebyshev function as a function of the guide wavelength of the waveguide are set in the pass band of the impedance transformer, and the frequencies corresponding to the guide wavelength of the plurality of zero points. Is defined as the reflection zero frequency, and the axial length and height or width of the waveguide as design parameters are determined so that the reflection is minimized at the reflection zero frequency. Even for large waveguide impedance transformers, the above-mentioned design that obtains the desired reflection characteristics close to the ideal characteristics by the Chebyshev function at all frequencies within the pass band by the optimization method using the minimum frequency etc. You can determine the value of the parameter.

In the twentieth invention, a plurality of zero points of the Chebyshev function as a function of the guide wavelength of the waveguide are set in the pass band of the impedance transformer, and the frequencies corresponding to the guide wavelength of the plurality of zero points. Is defined as the reflection zero frequency, the axial length and height or width of the waveguide as design parameters are determined so that the reflection is minimized at the reflection zero frequency, and the above-mentioned guide obtained using the above dimensions is determined. Of the reflection characteristics of the wave tube type impedance transformer, select a frequency with a larger reflection than the ideal Chebyshev transformer characteristic so that the reflection becomes less than a predetermined magnitude at the above reflection large frequency and the reflection zero frequency. Since the axial length and height or width of the above-mentioned waveguide was determined, the optimization was performed multiple times, and the frequency change of the susceptance due to steps was changed. Even for a particularly large waveguide impedance transformer, the desired reflection characteristics very close to the ideal characteristics due to the Chebyshev function can be obtained at all frequencies within the pass band by the optimization method using the minimum frequency. It is possible to determine the values of the above-mentioned design parameters that are set.

In the twenty-first aspect of the invention, a plurality of local maximum points of the Chebyshev function as a function of the internal wavelength of the waveguide are set in the pass band of the impedance transformer to correspond to the internal wavelengths of the multiple maximum points. Frequency is defined as the reflection maximum frequency, and the axial length and height or width of the waveguide as design parameters are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency. Even for a waveguide type impedance transformer with a particularly large frequency change, the desired reflection characteristics close to the ideal characteristics due to the Chebyshev function at all frequencies within the pass band by the optimization method using the minimum frequency. The values of the above design parameters obtained can be determined.

In the twenty-second aspect, a plurality of local maximum points of the Chebyshev function as a function of the internal wavelength of the waveguide are set in the pass band of the impedance transformer, and the maximum internal points correspond to the internal wavelengths of the multiple maximum points. Frequency is defined as the reflection maximum frequency, and the axial length and height or width of the waveguide as design parameters are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency, and the above dimensions are used. Of the reflection characteristics of the waveguide type impedance transformer obtained as described above, a frequency with a larger reflection is selected than the characteristic of the ideal Chebyshev transformer, and the reflection has a predetermined magnitude at the large reflection frequency and the maximum reflection frequency. Since the axial length and height or width of the above-mentioned waveguide are determined so as to be equal to or less than the above, the characteristic of the frequency change of the susceptance due to the step is determined. Even for large waveguide impedance transformers, the desired reflection characteristics very close to the ideal characteristics due to the Chebyshev function can be obtained at all frequencies within the pass band by optimization methods using the minimum frequency. The values of the above design parameters can be determined.

[0057]

【Example】

Example 1. FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing the shape of an inner conductor pattern. In the figure, 1a and 1b are dielectric substrates, 2a is a dielectric substrate 1
a is an outer conductor formed by adhering a conductor film to the entire surface of one side of a, 3, 6 and 7 are inner conductors formed by adhering a conductor film to the other surface of the dielectric substrate 1a, and 9 is Dielectric substrate 1
a, 1b, outer conductors 2a, 2b, and a through hole penetrating through the inner conductor 3, the outer conductors 2a, 2b, and a through hole formed by closely adhering a conductor film continuous with the inner conductor 3 to the inner peripheral surface of the through hole. , 30 is a strip line resonator composed of dielectric substrates 1a and 1b, outer conductors 2a and 2b, and inner conductor 3, and 60 is composed of dielectric substrates 1a and 1b, outer conductors 2a and 2b, and inner conductor 6. A stripline input line, 70 is a stripline output line composed of dielectric substrates 1a and 1b, outer conductors 2a and 2b, and inner conductor 7, P1 is an input end, and P2 is
Is an output terminal. The dielectric substrates 1a and 1b are composed of the inner conductor 3,
6 and 7 are overlapped so as to sandwich them.
The length of each of the plurality of inner conductors 3 is set to about 1/4 wavelength, and one end of each of the plurality of inner conductors 3 is provided with a through hole 9 to form the outer conductors 2a,
It is connected to b and short-circuited. Therefore, the resonator 30 is a quarter-wave resonator in which one end is short-circuited and the other end is open. All of the plurality of resonators 30 are arranged in parallel, and adjacent ones are alternately short-circuited at one end on the opposite w side by the through hole 9.

Next, the operation will be described. Since the adjacent resonators 30 are arranged such that the short-circuited end and the open end face each other, they are coupled to each other by an electric field. The amount of coupling is adjusted by the distance between the inner conductors 3 or the width of the inner conductors 3.

Now, assuming that the length of each of the inner conductors 3 is set to a predetermined length in the vicinity of a quarter wavelength and all the resonators 30 resonate at the same frequency, for example, f0, that frequency. At f0, the resonators 6 in the resonance state are strongly coupled to each other, and the resonator 3 at the first stage of the incident wave to the input line 60 is
It is guided to 0 and is repeatedly coupled to the adjacent resonator by the electric field, and is output from the output line 70. However, at frequencies other than f0, the coupling between the resonators 30 is very weak, and most of the power of the incident wave on the input line 60 is reflected. As described above, the stripline filter shown in FIGS. 1 and 2 has a function as a bandpass filter.

Next, the flow of the design procedure will be described with reference to FIG. First, in step 1, a bandpass filter having an ideal Chebyshev characteristic formed by a lumped constant element modified from the original lowpass filter and the equivalent of the distributed constant type determined according to the physical shape of the filter of FIG. Compare the circuits at the center frequency of the pass band of the filter,
Initial design of the resonator spacing, the resonator width, and the resonator length as design parameters is performed. Step 1 is shown in FIG.
It is similar to the conventional design procedure shown in FIG. At this time,
A pair resonator in which only two adjacent resonators are taken out in the filter of FIG. 1 is represented by an equivalent circuit composed of distributed constant lines as shown in FIG. In FIG. 4, 10 is an equivalent circuit of a tip short-circuit stub having an electrical length θ, and 11 is an equivalent circuit of a line having an electrical length θ. By using the equivalent circuits of FIG. 4 in combination, the filter of FIG. 1 can be represented by a distributed constant line type equivalent circuit similar to that shown in FIG.

Next, in step 2, frequencies above the number of design parameters are selected, and as shown in FIG. 5, the insertion loss or reflection loss at these frequencies is defined.
FIG. 5 is a diagram showing desired pass and reflection characteristics of the filter of FIG. 1, where f1 to f13 are selected frequencies. In order to make the levels of the specified pass loss and reflection loss the same, the reflection loss is defined at frequencies f2 to f10 in the pass band, and the pass loss is defined at frequencies f1 and f11 to f13 outside the pass band.

Finally, in step 3, the characteristics of the filter by the distributed constant line type equivalent circuit are calculated, and the reflection loss value at the frequencies f2 to f10 and the insertion loss at the frequencies f1 and f11 to f13 are set to desired values. The parameters of the equivalent circuit are optimized so that The resonator spacing, the resonator width, and the resonator length are obtained from the parameters obtained by the optimization.

As described above, in the embodiment according to the design procedure of FIG. 3, the reflection loss is defined to be a desired value at a plurality of frequencies within the pass band. Therefore, even when the pass band is wide, the reflection loss is small. There is little increase in reflection and good properties are obtained over the entire pass band.

Further, since the frequency is selected by the number of parameters or more, the relational expression is obtained by the number of parameters or more, and it is highly possible that the characteristic calculation result by the equivalent circuit approaches the desired characteristic upon optimization.

Example 2. FIG. 6 is a flow chart showing the design procedure of another embodiment of the present invention.
This is a case where the zero reflection and the maximum frequency of the Chebyshev characteristic are selected in the pass band and the reflection loss at these frequencies is specified as shown in FIG. FIG. 7 is a diagram showing a desired reflection characteristic of the filter shown in FIG.
1, f3, f5, and f7 are reflection zero frequencies and are given by the following second equation.

[0066]

[Equation 1]

Further, f2, f4, and f6 are reflection maximum frequencies, which are given by the following third equation.

[0068]

[Equation 2]

As described above, the embodiment according to the design procedure of FIG. 6 defines all the reflection zero frequencies within the pass band, and therefore, even when the pass band is wide, the reflection at the end of the pass band is increased or the reflection zero is reduced. There is little frequency shift, and ideal Chebyshev function reflection characteristics can be obtained over the entire pass band.

Since the number of zero reflections and the maximum frequency is less than the total number of parameters, all parameters cannot be specified as variables during optimization. For example, only the resonator spacing is specified as a variable and other parameters are specified. On the other hand, good reflection characteristics can be realized by correcting the resonator length and the resonator width so that the resonance frequency and the characteristic impedance of each resonator do not change due to the change of the resonator spacing.

Therefore, the embodiment according to the design procedure of FIG.
Similar to the case of FIG. 3, in addition to being able to obtain a wideband stripline filter, it has the advantage that good reflection characteristics can be obtained by only defining the reflection loss for a small number of frequencies.

Example 3. FIG. 8 is a flow showing a design procedure of another embodiment of the present invention.
This is the case where the reflection zero frequencies of the Chebyshev characteristic are selected in the pass band and the reflection loss at these frequencies is specified as shown in FIG. FIG. 9 shows a desired reflection characteristic of the filter shown in FIG. 1. In the figure, f1, f3, f5, and f7 are reflection zero frequencies, which are given by the second equation as in the case of FIG.

As described above, since the embodiment according to the design procedure of FIG. 8 defines all reflection zero frequencies within the pass band, even if the pass band is wide, the increase in reflection at the end of the pass band and the reflection zero will occur. There is little frequency shift, and ideal Chebyshev function reflection characteristics can be obtained over the entire pass band.

Since the number of reflection zero frequencies is the same as the number of resonators, all parameters cannot be specified as variables in optimization, but only the resonator spacing is specified as a variable.
With respect to other parameters, good reflection characteristics can be realized by correcting the resonator length and the resonator width so that the resonance frequency and the characteristic impedance of each resonator do not change due to the change of the resonator spacing.

Therefore, the embodiment according to the design procedure of FIG.
Similar to the case of FIG. 3, in addition to being able to obtain a wideband stripline filter, it has an advantage that a good reflection characteristic can be obtained only by defining reflection loss for a smaller number of frequencies.

Example 4. FIG. 10 is a flow chart showing the design procedure of another embodiment of the present invention. In step 2, the reflection maximum frequencies of the Chebyshev characteristic are selected in the pass band, and as shown in FIG. 11, reflection at these frequencies is performed. This is the case when the loss is specified. FIG. 11 shows a desired reflection characteristic of the filter shown in FIG. 1. In the figure, f2, f4, and f6 are reflection maximum frequencies, which are given by the equation (2) as in the case of FIG.

As described above, in the embodiment according to the design procedure of FIG. 10, since all reflection maximum frequencies within the pass band are specified, even if the pass band is wide, the reflection at the end of the pass band and the reflection maximum are increased. The frequency shift is small, and a characteristic close to the ideal reflection characteristic by the Chebyshev function can be obtained over the entire pass band. However, in this case, the reflection characteristic using the equivalent circuit parameter obtained by the optimization is shown in FIG.
Note that the maximum value may be larger than the specified maximum value as shown in.

Since the number of reflection maximum frequencies is one less than the number of resonators, all parameters cannot be specified as variables for optimization, but only the resonator spacing is specified as a variable and other parameters are specified. A good reflection characteristic can be realized by correcting the resonator length and the resonator width so that the resonance frequency and the characteristic impedance of each resonator do not change due to the change of the resonator spacing.

Therefore, as in the case of FIG. 3, the embodiment according to the design procedure of FIG. 10 can obtain a wide band strip line filter and also defines the reflection loss for a minimum number of frequencies. This has the advantage that a good reflection property can be obtained by itself.

Example 5. FIG. 12 is a flow chart showing the design procedure of another embodiment of the present invention. Further, in addition to the embodiment of FIG. 10, in step 4, the reflection characteristics obtained up to step 3 are ideal Chebyshev characteristics. This is a case in which a frequency having a larger reflection than the ideal characteristic is selected as compared with the reflection characteristic of, and the reflection loss at this frequency is set as a new constraint condition. The new frequencies are given as, for example, f8 and f9 in FIG.

In step 5, f2, f4, f6, f
It is optimized again with the reflection loss of 8 and f9 as constraint conditions, and the resonator spacing, the resonator width, and the resonator length are obtained from the obtained parameters.

As described above, the embodiment according to the design procedure of FIG. 12 defines all reflection maximum frequencies within the pass band, so that even if the pass band is wide, the increase in reflection at the end of the pass band and the reflection maximum. Since the frequency shift is small and the optimization is performed a plurality of times, ideal Chebyshev function reflection characteristics can be obtained over the entire pass band.

Since the number of reflection maximum frequencies is one less than the number of resonators, all parameters cannot be specified as variables for optimization, but only the resonator spacing is specified as a variable and other parameters are specified. A good reflection characteristic can be realized by correcting the resonator length and the resonator width so that the resonance frequency and the characteristic impedance of each resonator do not change due to the change of the resonator spacing.

Therefore, the embodiment according to the design procedure of FIG. 12 can obtain a wide band strip line filter as in the case of FIG. 3, and only specifies the reflection loss for a small number of frequencies. Has an advantage that a good reflection characteristic can be obtained.

In the description of the above embodiment, the case where the reflection maximum frequency of the Chebyshev characteristic is selected in the pass band in step 2 has been described, but in step 2, the reflection zero frequency of the Chebyshev characteristic is selected in the pass band. Even if is selected, an ideal reflection characteristic by the Chebyshev function can be obtained over the entire pass band.

Example 6. FIG. 14 is a schematic configuration diagram showing another embodiment of the present invention. In the figure, 12 is a rectangular waveguide, 13 is an inductive iris, and 14 is a cavity resonator whose both ends are partitioned by the inductive iris 13. , P1 is the input end,
P2 is an output terminal. The cavity resonator 14 is a half-wave resonator whose both ends are substantially short-circuited.

Next, the operation will be described. Adjacent cavity resonators 14 are coupled to each other via inductive iris 13, and the amount of coupling is adjusted by the size of inductive iris 13.

Now, the length of each cavity resonator 14 is 1 /
It is set to a predetermined length near two wavelengths, and all cavity resonators 1
Assuming that 4 resonates at the same frequency, for example, f0, at that frequency f0, the cavity resonators 14 in the resonance state are strongly coupled to each other, and the incident wave to the input end P1 is the first stage. Is guided to the cavity resonator 14 and is coupled to the adjacent resonator mainly by the magnetic field, and the output terminal P2
Will be output. However, at frequencies other than f0, the coupling between the cavity resonators 14 is very weak, and the input end P
Most of the electric power of the incident wave on 1 is reflected. Thus, the waveguide filter shown in FIG. 14 has a function as a bandpass filter.

Next, the flow of the design procedure will be described with reference to FIG. First, in step 1, the bandpass filter having an ideal Chebyshev characteristic which is modified from the original lowpass filter and is composed of lumped constant elements, and the distribution constant type equivalent determined according to the physical shape of the filter of FIG. The circuits are compared at the center frequency of the pass band of the filter, and the resonator length as a design parameter and the susceptance value of the inductive iris are initially designed. Step 1 is similar to the conventional design procedure shown in FIGS. 38 to 41. At this time, the equivalent circuit of the inductive iris 13 in the filter of FIG. 14 is represented by the parallel susceptance Ba as shown in FIG. Here, the parallel susceptance Ba is a function of the spacing d of the inductive iris and the wavelength in the waveguide. The equivalent circuit of the inductive post is as shown in FIG. 17 and can be used instead of the inductive iris. Using the relationship of FIG. 16, the filter of FIG. 14 is represented by the distributed constant type equivalent circuit of FIG.

Next, in step 2, as shown in FIG. 18, zero points of the Chebyshev function as a function of the waveguide internal wavelength are set in the pass band, and the frequencies corresponding to the internal wavelengths of the plurality of zeros are set. It is defined as the reflection zero frequency,
It defines the return loss at these frequencies. The characteristic indicated by the solid line in FIG. 18 is the desired reflection characteristic of the filter of FIG. In the figure, f1 to f11 are reflection zero frequencies, and the corresponding waveguide internal wavelength λgp is given by the following equation (4).

[0091]

(Equation 3)

Here, ωp / ω1 is the reflection zero frequency of the original low-pass filter, λg0 is the guide wavelength at the center frequency, and λg1 and λg2 are the guide wavelengths at the lower and upper limits of the pass band, respectively.

Finally, in step 3, the characteristics of the filter using the distributed constant line type equivalent circuit are calculated, and the parameters of the equivalent circuit are optimized so that the reflection loss values at the frequencies f1 to f11 are desired values. To do. From the parameters obtained by the optimization, the cavity length and the size of the inductive iris can be obtained. At this time, the susceptance value Bi of the i-th inductive iris obtained by optimization is the susceptance value B0i in the initial design and N is the number of resonator stages.
Then, it can be obtained within the range of the following first equation.

1 <Bi / B0i <1.2 (1 ≦ i ≦ 0.2N, N ≦ i ≦ N + 1) 0.8 <Bi / B0i <1 (0.2N <i ≦ 0.4, 0.8N ≦ i <N) 0.9 <Bi / B0i ≦ 1 (0.4N <i <0.8N)

As described above, since the embodiment according to the design procedure of FIG. 15 defines all reflection zero frequencies within the pass band, even if the pass band is wide, the reflection at the end of the pass band is increased or the reflection zero is reduced. There is little frequency shift, and ideal Chebyshev function reflection characteristics can be obtained over the entire pass band.

Since the number of reflection zero frequencies is the same as the number of resonators, all parameters cannot be specified as variables for optimization, but for example, only the susceptance value of the inductive iris 13 is specified as a variable. However, with respect to other parameters, by correcting the resonator length so that the resonance frequency of each resonator does not change due to the change in the susceptance value of the inductive iris 13, good reflection characteristics can be realized.

Therefore, in the embodiment according to the design procedure of FIG. 15, a broadband waveguide filter can be obtained, and a reflection characteristic can be improved by only defining the reflection loss for a small number of frequencies. Has the advantage that

It is also possible to apply the sixth embodiment to the fifth embodiment to perform the optimization again, and the Chebyshev function is applied to all frequencies in the pass band by the optimization method using the minimum frequency. It is possible to determine the value of the above-mentioned design parameter that gives a desired reflection characteristic very close to the ideal characteristic of

Example 7. FIG. 19 is a flow chart showing the design procedure of another embodiment of the present invention. In step 2, the reflection maximum frequencies are selected from the characteristics of the initial design within the pass band, and as shown in FIG. This is the case when the reflection loss in is defined. , In FIG.
f1 to f6 are the selected reflection maximum frequencies, and the solid line is f
It is the reflection characteristic after the reflection loss in 1 to f6 is defined and optimized. Compared with the characteristic of the wavy line obtained from the initial design, the reflection characteristic is greatly improved.

As described above, in the embodiment according to the design procedure of FIG. 19, since the reflection maximum value is defined at a plurality of frequencies within the pass band, even if the pass band is wide, the reflection at the end of the pass band does not increase. A small reflection loss can be obtained over the entire pass band. However, in this case, the reflection characteristic using the equivalent circuit parameter obtained by the optimization may have a maximum value larger than the specified maximum value. In this case, the same optimization as that shown in the fifth embodiment is performed. Need to do.

Since the maximum number of reflection maximum frequencies is one less than the number of resonators, all parameters cannot be specified as variables for optimization. For example, only the susceptance value of the inductive iris 13 is used as a variable. Good reflection characteristics can be realized by specifying the other parameters and correcting the resonator length so that the resonance frequency of each resonator does not change due to the change in the susceptance value of the inductive iris 13.

Therefore, in the embodiment according to the design procedure of FIG. 19, a broadband waveguide filter can be obtained as in the case of FIG. 15, and reflection loss is caused for a minimum number of frequencies. It has an advantage that a good reflection property can be obtained only by defining.

Example 8. FIG. 21 is a schematic configuration diagram showing another embodiment of the present invention. In the figure, 1 is a dielectric substrate, 2 is an outer conductor formed by closely adhering a conductor film on one entire surface of the dielectric substrate 1. , 15 is a strip conductor formed by closely adhering a conductor film to the other surface of the dielectric substrate 1, 16 is a microstrip line including the dielectric substrate 1, the outer conductor 2, and the inner conductor 15, and 17 is a microstrip. 1/4 wavelength line forming a part of the line 16, P1 is an input end,
P2 is an output terminal. Here, four 1/4 wavelength lines 1
The line width of 7 is set to be wider as it is closer to the output terminal P2 side.

Next, the operation will be described. Since the one-quarter wavelength line 17 is set to have a wider line width as it is closer to the output end P2 side, there is a line width discontinuity on the connection surface between adjacent ones. In this discontinuity, reflection occurs according to the size of the discontinuity.

Now, assuming that the line lengths of all the 1/4 wavelength lines 17 are set to be 1/4 wavelength at a predetermined frequency f0, the radio wave of the frequency f0 incident from the input end P1 is initially Partly reflected due to the discontinuity of. The radio wave that has passed through the first discontinuity passes through the second quarter wavelength line 17 and is partially reflected again at the second discontinuity. However, 1
Since the line length of the / 4 wavelength line 17 is set to ¼ wavelength at f0, the reflected wave reflected at the second discontinuity is the first at the first discontinuity when returning to the first discontinuity. The phase is 180 degrees, that is, 1
/ Delay by two wavelengths. Therefore, these two reflected waves cancel each other out, and by adjusting the relative magnitude of the discontinuity, it is possible to never return to the input end P1. For the third and subsequent discontinuities, mutual reflection can be canceled by the same principle. Therefore, the incident from the input end P1 with a narrow line width and high impedance hardly reflects when the frequency is f0. , Is output from the output terminal P2 having a wide line width and a low impedance. Thus, FIG.
The strip line shown in 1 has a function as an impedance transformer.

Next, the flow of the design procedure will be described with reference to FIG. First, in step 1, 1 is set as a design parameter according to a conventional design procedure that does not consider the frequency characteristic of the susceptance due to the discontinuity between the quarter wavelength lines.
Initial design of line length and characteristic impedance of / 4 wavelength line. Step 1 is the same as the conventional design procedure shown in FIGS. 43 and 44. At this time, two adjacent quarter-wave lines 17 in the impedance transformer of FIG.
The discontinuity between is represented by a parallel susceptance as shown in FIG. In FIG. 23, B12 is a parallel susceptance due to discontinuity, and Z1 and Z2 are characteristic impedances of the ¼ wavelength line 17 at both ends. By using the equivalent circuits of FIG. 23 in combination, the filter of FIG. 21 can be represented by an equivalent circuit similar to that shown in FIG.

Next, in step 2, frequencies higher than the number of design parameters are selected, and as shown in FIG. 5, the insertion loss or reflection loss at these frequencies is specified.
FIG. 24 is a diagram showing desired passage and reflection characteristics of the impedance transformer of FIG. 21, in which f1 to f1 are shown.
3 is the selected frequency. Here, a reflection loss having a frequency characteristic larger than the insertion loss is specified.

Finally, in step 3, the characteristics of the filter are calculated by the equivalent circuit, and the frequencies f1 to f13 are calculated.
The electrical length and the characteristic impedance of the 1/4 wavelength line, which are the parameters of the equivalent circuit, are optimized so that the value of the reflection loss at is a desired value. From the parameters obtained by the optimization, the line length and line width of the quarter wavelength line are obtained.

As described above, in the embodiment of FIG. 21 according to the design procedure of FIG. 22, the reflection loss is defined to be a desired value at a plurality of frequencies within the pass band. Therefore, even if the pass band is wide, There is little increase in reflection at the edges and good performance is obtained over the entire pass band.

Further, since the frequency is selected in the number of parameters or more, the relational expression is obtained in the number of parameters or more, and it is highly possible that the characteristic calculation result by the equivalent circuit approaches the desired characteristic during optimization.

Example 9. FIG. 25 is a flow chart showing the design procedure of another embodiment of the present invention. In step 2, the reflection zero and the maximum frequency of the Chebyshev characteristic are selected in the pass band, and as shown in FIG. This is the case when the reflection loss in is defined. 26 is the same as FIG.
It is a figure which shows the desired reflection characteristic of the impedance transformer of No. 1, and the frequency and reflection loss which prescribe | regulate. In the figure, f
1, f3, f5, and f7 are reflection zero frequencies, f2, f4,
Also, f6 is a reflection maximum frequency, which is obtained in the same manner as in the conventional case.

As described above, in the embodiment according to the design procedure of FIG. 25, all reflection zeros and maximum frequencies in the pass band are defined. Therefore, even when the pass band is wide, the reflection at the end of the pass band does not increase. It is possible to obtain an ideal reflection characteristic by the Chebyshev function over the entire pass band.

Since the number of zero reflections and the maximum frequency is less than the total number of parameters, it is impossible to specify all parameters as variables for optimization. For example, only the characteristic impedance of the quarter wavelength line 17 is used as a variable. Specify,
Corresponding to changes in the characteristic impedance, the phase difference between the discontinuity, that is, the parallel susceptance does not change.
By correcting the electrical length of the four-wavelength line 17 in a dependent manner, good reflection characteristics can be realized.

Therefore, in the embodiment according to the design procedure of FIG. 25, as in the case of FIG. 22, a broadband stripline impedance transformer can be obtained, and reflection loss is defined for a small number of frequencies. This has the advantage that a good reflection property can be obtained by itself.

Example 10. FIG. 27 is a flow chart showing the design procedure of another embodiment of the present invention. In step 2, reflection zero frequencies of Chebyshev characteristic are selected in the pass band, and as shown in FIG. 28, reflection at these frequencies is performed. This is the case when the loss is specified. FIG. 28 is a diagram showing desired reflection characteristics of the impedance transformer of FIG. In the figure, f1, f3, f
5 and f7 are reflection zero frequencies, which are obtained as in the conventional case.

As described above, in the embodiment according to the design procedure of FIG. 27, since all reflection zero frequencies within the pass band are specified, even if the pass band is wide, the increase in reflection at the pass band edge or the reflection zero is generated. There is little frequency shift, and ideal Chebyshev function reflection characteristics can be obtained over the entire pass band.

Since the number of reflection zero frequencies is the same as the number of quarter-wave lines, all parameters cannot be specified as variables for optimization. For example, the characteristic impedance of the quarter-wave line 17 is not specified. By specifying only as a variable and correcting the electrical length of the 1/4 wavelength line 17 in a dependent manner so that the phase difference between the discontinuities, that is, the parallel susceptance does not change in response to the change in the characteristic impedance, it is good. It is possible to realize various reflection characteristics.

Therefore, in the embodiment according to the design procedure of FIG. 27, as in the case of FIG. 25, a broadband stripline impedance transformer can be obtained, and reflection loss is defined for a smaller number of frequencies. There is an advantage that a good reflection characteristic can be obtained only by

Example 11. FIG. 29 is a flow chart showing the design procedure of another embodiment of the present invention. In step 2, the reflection maximum frequencies of the Chebyshev characteristic are selected in the pass band, and as shown in FIG. 30, reflection at these frequencies is performed. This is the case when the loss is specified. FIG. 29 is a diagram showing desired reflection characteristics of the impedance transformer of FIG. 21, prescribed frequencies and reflection loss. In the figure, f2, f4, and f6 are reflection zero frequencies, which are obtained as in the conventional case.

As described above, in the embodiment according to the design procedure of FIG. 29, since all reflection maximum frequencies within the pass band are specified, even if the pass band is wide, the increase in reflection at the end of the pass band and the reflection maximum are obtained. The frequency shift is small, and a characteristic close to the ideal reflection characteristic by the Chebyshev function can be obtained over the entire pass band. However, in this case, the reflection characteristic using the equivalent circuit parameter obtained by the optimization is shown in FIG.
Note that the maximum value may be larger than the specified maximum value as shown in.

Since the number of reflection maximum frequencies is one less than the number of quarter wavelength lines, all parameters cannot be specified as variables for optimization. For example, only the characteristic impedance of quarter wavelength line 17 is specified. Is designated as a variable, and the electrical length of the ¼ wavelength line 17 is dependently corrected so that the phase difference between the parallel susceptances does not change in response to the change in the characteristic impedance. A reflective characteristic can be realized.

Therefore, as in the case of FIG. 25, the embodiment according to the design procedure of FIG. 29 can obtain a wideband stripline impedance transformer and also has a reflection loss for a minimum number of frequencies. It has an advantage that a good reflection property can be obtained only by defining

Example 12. FIG. 31 is a flow chart showing the design procedure of another embodiment of the present invention. In addition to the embodiment of FIG. 29, in step 4, the reflection characteristics obtained up to step 3 are converted into ideal Chebyshev characteristics. This is a case in which a frequency having a larger reflection than the ideal characteristic is selected as compared with the reflection characteristic of, and the reflection loss at this frequency is set as a new constraint condition. New frequencies are given, for example, as f8 and f9 in FIG.

In step 5, f2, f4, f6, f
The line length and line width of the ¼ wavelength line are obtained from the obtained parameters by optimizing again with the reflection loss of 8 and f9 as constraint conditions.

As described above, in the embodiment according to the design procedure of FIG. 31, since all reflection maximum frequencies within the pass band are specified, even if the pass band is wide, the increase in reflection at the end of the pass band and the reflection maximum. Since the frequency shift is small and the optimization is performed a plurality of times, ideal Chebyshev function reflection characteristics can be obtained over the entire pass band.

Since the number of reflection maximum frequencies is one less than the number of quarter wavelength lines, all parameters cannot be specified as variables for optimization. For example, only the characteristic impedance of quarter wavelength line 17 is specified. Is designated as a variable, and the electrical length of the ¼ wavelength line 17 is dependently corrected so that the phase difference between the parallel susceptances does not change in response to the change in the characteristic impedance. A reflective characteristic can be realized.

Therefore, in the embodiment according to the design procedure of FIG. 31, as in the case of FIG. 25, a broadband stripline impedance transformer can be obtained, and reflection loss is defined for a small number of frequencies. There is an advantage that a good reflection characteristic can be obtained only by

Example 13. FIG. 33 is a schematic configuration diagram of another embodiment of the present invention and is a diagram showing an impedance transformer using a rectangular waveguide. In the figure, 18 is a rectangular waveguide, 19 is a quarter wavelength waveguide, P1 is an input end, and P2 is an output end. The four quarter-wave waveguides 19 are output terminals P
The closer to the second side, the higher the height is set.

Next, the operation will be described. Since the height of the 1/4 wavelength waveguide 19 is set to be closer to the output end P2 side, the height of the waveguide is discontinuous on the connecting surface between adjacent waveguides. . In this discontinuity, reflection occurs according to the size of the discontinuity.

Now, assuming that the lengths of all the 1/4 wavelength waveguides 19 are set to be the 1/4 wavelength as the guide wavelength at the predetermined frequency f0, the frequency incident from the input end P1. The radio wave of f0 is partially reflected at the first discontinuity. The radio wave passing through the first discontinuity passes through the second quarter-waveguide 19 and is partially reflected again at the second discontinuity. However, since the line length of the 1/4 wavelength waveguide 19 is set to 1/4 wavelength at f0, the reflected wave reflected at the second discontinuity is 1 when returning to the first discontinuity.
Phase 1 compared to the first reflected wave at the th discontinuity
It is delayed by 80 degrees, that is, 1/2 wavelength. Therefore, these two
The two reflected waves cancel each other out, and by adjusting the relative size of the discontinuity, it is possible to completely return to the input terminal P1. For the third and subsequent discontinuities, mutual reflections can be canceled by the same principle. Therefore, the incidence from the input end P1 having a low waveguide height and a low impedance is almost zero when the frequency is f0. It is taken out from the output end P2 which is not reflected and has a high waveguide height and high impedance. As described above, the waveguide circuit shown in FIG. 33 has a function as an impedance transformer.

Generally, since the waveguide wavelength of the waveguide has a dispersibility with respect to the frequency, the electrical length of the waveguide is proportional to the reciprocal of the waveguide wavelength, but not proportional to the frequency. Also in the impedance transformer of FIG. 33, the Chebyshev function used as the ideal reflection characteristic needs to be considered as a function of the guide wavelength.

By using the guide wavelength of the Chebyshev function with zero slope in place of the frequency with zero slope of the Chebyshev function in Embodiments 8 to 12 according to FIG.
The impedance transformer can be applied with the same design procedure as that shown in Examples 8 to 12, and can realize a wide band.

Although the high frequency filters shown in Examples 1 to 7 have four or eleven resonators, the number of resonators is one to three, five to ten, or twelve or more. The same advantages and effects as those of the embodiment can be obtained.

Further, the impedance transformers shown in Examples 8 to 13 have been described for the case where the number of quarter-wave lines or waveguides is four, but even if the number of stages is one to three or five or more. Often, the same advantages and effects as those of the embodiment are obtained.

Further, in the above embodiments, the case where the Chebyshev function is used as the transfer function has been shown, but any function capable of setting a plurality of zero points or maximum and minimum points in the pass band, such as Bessel function and elliptic function, is shown. It goes without saying that the design procedure used for the high frequency filter or the impedance transformer of the present invention can be similarly applied.

[0136]

As described above, according to the first aspect of the present invention, not only the center frequency but also a plurality of frequencies within the selected frequency range are used to set the conditional expressions equal to or more than the number of design parameters, and the optimum Even if the pass band is wide, the values of the above-mentioned design parameters by which the desired reflection characteristics can be obtained can be determined by the optimization method, etc., and a high-frequency filter with small reflection over a wide band can be obtained.

According to the second aspect of the present invention, the value of the design parameter that can obtain a desired reflection characteristic close to the ideal characteristic by the Chebyshev function can be determined at all frequencies in the pass band by the optimization method, etc. Therefore, there is an effect that a high-frequency filter with small reflection can be obtained.

According to the third aspect of the present invention, a design parameter that obtains a desired reflection characteristic close to an ideal characteristic by the Chebyshev function at all frequencies in the pass band by an optimization method using the minimum frequency or the like. The value of can be determined, and a high-frequency filter with small reflection over a wide band can be obtained.

Further, according to the invention of claim 4, optimization is performed a plurality of times by an optimization method using the minimum frequency, and the ideal characteristic by the Chebyshev function is very high at all frequencies in the pass band. It is possible to determine the value of a design parameter that can obtain a desired reflection characteristic close to that, and it is possible to obtain a high-frequency filter with small reflection over a wide band.

According to the invention of claim 5, a desired reflection characteristic very close to the ideal characteristic by the Chebyshev function can be obtained at all frequencies in the pass band by an optimization method using the minimum frequency. The value of the design parameter can be determined, and a high-frequency filter with small reflection over a wide band can be obtained.

According to the invention of claim 6, a desired reflection characteristic very close to an ideal characteristic by the Chebyshev function can be obtained at all frequencies in the pass band by an optimization method using the minimum frequency. The value of the design parameter can be determined, and a high-frequency filter with small reflection over a wide band can be obtained.

Further, according to the invention of claim 7, even for a waveguide type filter in which the frequency variation of the electrical length is particularly large,
It is possible to determine the value of the design parameter that gives the desired reflection characteristic close to the ideal characteristic by the Chebyshev function at all frequencies in the pass band by using the optimization method using the minimum frequency, so that There is an effect that a small high frequency filter can be obtained.

Further, according to the invention of claim 8, even for a waveguide type filter in which the frequency variation of the electrical length is particularly large,
It is optimized multiple times by the optimization method using the minimum frequency, etc., and the value of the design parameter that obtains the desired reflection characteristic very close to the ideal characteristic by the Chebyshev function is determined at all frequencies in the pass band. Therefore, there is an effect that a high frequency filter having a small reflection over a wide band can be obtained.

Further, according to the invention of claim 9, even for the waveguide type filter in which the frequency variation of the electrical length is particularly large,
It is possible to determine the design parameter value that gives the desired reflection characteristics close to the ideal characteristics by the Chebyshev function at all frequencies in the pass band by optimization methods using the minimum frequency, and the reflection is small over a wide band. There is an effect that a high frequency filter can be obtained.

Further, according to the invention of claim 10, even with respect to the waveguide type filter in which the frequency change of the electrical length is particularly large, the optimization can be performed a plurality of times by the optimization method using the minimum frequency. It is possible to determine the value of the design parameter that obtains the desired reflection characteristic that is very close to the ideal characteristic by the Chebyshev function at all frequencies in the pass band, so that it is possible to obtain a high-frequency filter with small reflection over a wide band. is there.

According to the eleventh aspect of the invention, since the inductive iris or inductive post is used as the susceptance element in any of the seventh to tenth aspects of the invention, the iris width of the inductive iris or the inductive iris. The desired susceptance value can be easily obtained by adjusting the number, diameter, or spacing of the flexible posts, and a high susceptance value can be obtained, so a high-frequency filter with small reflection over a wide band can be obtained. There is an effect to be obtained.

According to the twelfth aspect of the present invention, even if the pass band is wide, desired reflection characteristics close to the ideal characteristics by the Chebyshev function can be obtained at all frequencies within the pass band, so that over a wide band. There is an effect that a high-frequency filter with small reflection can be obtained.

According to the thirteenth aspect of the present invention, not only the center frequency but also a plurality of frequencies within the selected frequency range are used to set the conditional expressions equal to or more than the number of design parameters.
Even if the pass band is wide by an optimization method or the like, it is possible to determine the value of the above-mentioned design parameter that can obtain a desired reflection characteristic, and it is possible to obtain an impedance transformer having a small reflection over a wide band.

According to the fourteenth aspect of the present invention, it is possible to determine the value of the design parameter that gives a desired reflection characteristic close to the ideal characteristic by the Chebyshev function at all frequencies in the pass band by the optimization method or the like, and the wide band can be determined. Therefore, there is an effect that an impedance transformer with small reflection can be obtained.

According to the fifteenth aspect of the present invention, a design parameter that obtains a desired reflection characteristic close to an ideal characteristic by the Chebyshev function at all frequencies in the pass band by an optimization method using the minimum frequency or the like. The value of can be determined, and an impedance transformer with small reflection over a wide band can be obtained.

According to the sixteenth aspect of the present invention, the optimization is performed a plurality of times by the optimization method using the minimum frequency, and the ideal characteristic by the Chebyshev function is very high at all frequencies in the pass band. It is possible to determine the value of a design parameter that can obtain a desired reflection characteristic close to the impedance, and to obtain an impedance transformer having a small reflection over a wide band.

According to the seventeenth aspect of the present invention, a design parameter that obtains a desired reflection characteristic close to the ideal characteristic by the Chebyshev function at all frequencies in the pass band by the optimization method using the minimum frequency or the like. The value of can be determined, and an impedance transformer with small reflection over a wide band can be obtained.

According to the eighteenth aspect of the present invention, the optimization is performed a plurality of times by the optimization method using the minimum frequency, and the ideal characteristic by the Chebyshev function is very high at all frequencies in the pass band. It is possible to determine the value of a design parameter that can obtain a desired reflection characteristic close to the impedance, and to obtain an impedance transformer having a small reflection over a wide band.

According to the nineteenth aspect of the invention, even for the waveguide type impedance transformer in which the frequency change of the susceptance due to the step is particularly large, the optimization method using the minimum frequency or the like can be used in the pass band. It is possible to determine the value of the design parameter that obtains a desired reflection characteristic close to the ideal characteristic by the Chebyshev function at all frequencies of, and it is possible to obtain an impedance transformer having a small reflection over a wide band.

According to the twentieth aspect of the invention, even for the waveguide type impedance transformer in which the frequency change of the susceptance due to the step is particularly large, the plurality of times are set by the optimization method using the minimum frequency. Optimized to determine the value of the design parameter that gives the desired reflection characteristic that is very close to the ideal characteristic by the Chebyshev function at all frequencies in the pass band, and an impedance transformer with low reflection can be obtained over a wide band. It is effective.

According to the twenty-first aspect of the invention, even for the waveguide type impedance transformer in which the frequency change of the susceptance due to the step is particularly large, the optimization method using the minimum frequency or the like can be used in the pass band. It is possible to determine the value of the design parameter that obtains a desired reflection characteristic close to the ideal characteristic by the Chebyshev function at all frequencies of, and it is possible to obtain an impedance transformer having a small reflection over a wide band.

According to the twenty-second aspect of the invention, even for the waveguide type impedance transformer in which the frequency change of the susceptance due to the step is particularly large, the plurality of times are obtained by the optimization method using the minimum frequency. By optimizing, it is possible to determine the values of the above design parameters that give the desired reflection characteristics that are very close to the ideal characteristics by the Chebyshev function at all frequencies in the pass band, and the impedance transformer with small reflection over a wide band can be obtained. There is an effect to be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a high frequency filter according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an inner conductor pattern of the high frequency filter according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a procedure for designing a high frequency filter according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an equivalent circuit of the resonator of the high-frequency filter according to the first embodiment of the present invention.

FIG. 5 is a diagram showing characteristics of the high frequency filter according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a design procedure of a high frequency filter according to a second embodiment of the present invention.

FIG. 7 is a diagram showing characteristics of a high frequency filter according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a design procedure of a high frequency filter according to a third embodiment of the present invention.

FIG. 9 is a diagram showing characteristics of a high frequency filter according to a third embodiment of the present invention.

FIG. 10 is a diagram showing a design procedure of a high frequency filter according to a fourth embodiment of the present invention.

FIG. 11 is a diagram showing characteristics of a high frequency filter according to a fourth embodiment of the present invention.

FIG. 12 is a diagram showing a design procedure of a high frequency filter according to a fifth embodiment of the present invention.

FIG. 13 is a diagram showing characteristics of a high frequency filter according to a fifth embodiment of the present invention.

FIG. 14 is a configuration diagram of a high frequency filter according to a sixth embodiment of the present invention.

FIG. 15 is a diagram showing a design procedure of a high frequency filter according to a sixth embodiment of the present invention.

FIG. 16 is a diagram illustrating a susceptance element for a high frequency filter according to a sixth embodiment of the present invention.

FIG. 17 is a diagram illustrating a susceptance element of a high frequency filter according to a sixth embodiment of the present invention.

FIG. 18 is a diagram showing a reflection characteristic of a high frequency filter according to a sixth embodiment of the present invention.

FIG. 19 is a diagram showing a design procedure for a high-frequency filter according to embodiment 7 of the present invention.

FIG. 20 is a characteristic of the high frequency filter according to the seventh embodiment of the present invention.

FIG. 21 is a diagram showing a schematic configuration of an impedance transformer according to Example 8 of the present invention.

FIG. 22 is a diagram showing a design procedure of the impedance transformer according to the eighth embodiment of the present invention.

FIG. 23 is a diagram showing the discontinuity of the impedance transformer according to the eighth embodiment of the present invention.

FIG. 24 is a diagram showing characteristics of an impedance transformer according to Example 8 of the present invention.

FIG. 25 is a diagram showing a design procedure of an impedance transformer according to a ninth embodiment of the present invention.

FIG. 26 is a diagram showing characteristics of the impedance transformer according to the ninth embodiment of the present invention.

FIG. 27 is a diagram showing a design procedure of the impedance transformer according to the tenth embodiment of the present invention.

FIG. 28 is a diagram showing characteristics of the impedance transformer according to the tenth embodiment of the present invention.

FIG. 29 is a diagram showing a design procedure of the impedance transformer according to the eleventh embodiment of the present invention.

FIG. 30 is a diagram showing characteristics of the impedance transformer according to the eleventh embodiment of the present invention.

FIG. 31 is a diagram showing a design procedure for an impedance transformer according to a twelfth embodiment of the present invention.

FIG. 32 is a diagram showing characteristics of the impedance transformer according to the twelfth embodiment of the present invention.

FIG. 33 is a perspective view showing a configuration of an impedance transformer according to Embodiment 13 of the present invention.

FIG. 34 is a diagram showing a design procedure of a conventional high frequency filter.

FIG. 35 is a circuit diagram of an original low-pass filter for explaining a conventional high-frequency filter design procedure.

FIG. 36 is a diagram showing an equivalent circuit of a conventional high frequency filter.

FIG. 37 is a diagram showing characteristics of a conventional high frequency filter.

FIG. 38 is a diagram showing a design procedure of a conventional high frequency filter.

FIG. 39 is a circuit diagram of an original low-pass filter for explaining a conventional high-frequency filter design procedure.

FIG. 40 is a diagram showing an equivalent circuit of a conventional high frequency filter.

FIG. 41 is a diagram showing an equivalent circuit of a conventional high frequency filter.

FIG. 42 is a diagram showing characteristics of a conventional high frequency filter.

FIG. 43 is a diagram showing a design procedure of a conventional impedance transformer.

FIG. 44 is a diagram showing an equivalent circuit of a conventional impedance transformer.

FIG. 45 is a diagram showing characteristics of an impedance transformer of a conventional example.

[Explanation of symbols]

1 dielectric substrate, 2 outer conductor, 3, 6, 7 inner conductor, 9
Through hole, 12 rectangular waveguide, 13 inductive iris, 14 cavity resonator, 15 strip conductor, 16
Microstrip line, 17 1/4 wavelength line, 1
8 rectangular waveguide, 19 1/4 wavelength waveguide, 30 strip line resonator, 60 input line, 70 output line.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hidenori Yukawa 5-1-1, Ofuna, Kamakura-shi Electronic Systems Research Laboratories, Mitsubishi Electric Corporation (72) Hideki Asao 5-1-1, Ofuna, Kamakura-shi Mitsubishi Electric Corporation Electronic Systems Laboratory (72) Inventor Shuji Urasaki 5-1, 1-1 Ofuna, Kamakura-shi Mitsubishi Electric Corporation Electronic Systems Laboratory

Claims (22)

[Claims] 1. A plurality of transmission line type resonators, inter-resonator coupling means for coupling the resonators to each other, and input / output coupling means for coupling the resonator and the input / output lines to each other. In the high frequency filter, the frequency is selected by a number equal to or more than the number of parameters that determine the resonator length of the resonator, the dimension of the inter-resonator coupling means, and the dimension of the input / output coupling means, and at the selected frequency. The resonator length of the resonator, the dimensions of the inter-resonator coupling means, and the dimensions of the input / output coupling means are determined so that the pass characteristic or the reflection characteristic of the high frequency filter approaches a desired value. High frequency filter. 2. A plurality of transmission line type resonators, inter-resonator coupling means for coupling the resonators to each other, and input / output coupling means for coupling the resonator and the input / output lines to each other. In the high frequency filter, a plurality of slope zero points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter, and frequencies corresponding to the plurality of slope zero points are reflected zero frequency or reflection. It is defined as the maximum frequency, and the resonator length of the resonator, the dimension of the inter-resonator coupling means, and the input / output coupling means of the resonator so that the reflection becomes minimum or maximum at the reflection zero frequency or the reflection maximum frequency. A high-frequency filter characterized in that its dimensions are determined. 3. A plurality of transmission line type resonators, inter-resonator coupling means for coupling the resonators to each other, and input / output coupling means for coupling the resonator and the input / output lines to each other. In the high frequency filter, a plurality of zero points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter, and the frequency corresponding to the plurality of zero points is defined as a reflection zero frequency, A high frequency filter characterized in that the resonator length of the resonator, the dimension of the inter-resonator coupling means, and the dimension of the input / output coupling means are determined so that the reflection is minimized at the reflection zero frequency. 4. A plurality of transmission line type resonators, inter-resonator coupling means for coupling the resonators to each other, and input / output coupling means for coupling the resonator and the input / output lines to each other. In the high frequency filter, a plurality of zero points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter, and the frequency corresponding to the plurality of zero points is defined as a reflection zero frequency, The resonator length of the resonator, the dimension of the inter-resonator coupling means, and the dimension of the input / output coupling means are determined so that the reflection is minimized at the reflection zero frequency, and the dimension is obtained by using the dimension. Of the reflection characteristics of the high frequency filter, select a frequency with a larger reflection than the ideal Chebyshev type filter characteristics, and A high frequency filter characterized in that a resonator length of the resonator, a dimension of the inter-resonator coupling means, and a dimension of the input / output coupling means are determined so as to be not more than a predetermined size. 5. A plurality of transmission line type resonators, inter-resonator coupling means for coupling the resonators to each other, and input / output coupling means for coupling the resonator and the input / output lines to each other. In the high frequency filter, a plurality of maximum points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter, and a frequency corresponding to the plurality of maximum points is specified as a reflection maximum frequency. The resonator length of the resonator, the dimension of the inter-resonator coupling means, and the dimension of the input-output coupling means are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency. High frequency filter to do. 6. A plurality of transmission line type resonators, inter-resonator coupling means for coupling the resonators to each other, and input / output coupling means for coupling the resonator and the input / output lines to each other. In the high frequency filter, a plurality of maximum points of the Chebyshev function as a function of the frequency of the radio wave in the resonator are set in the pass band of the high frequency filter, and a frequency corresponding to the plurality of maximum points is specified as a reflection maximum frequency. Then, the resonator length of the resonator, the dimension of the inter-resonator coupling means, and the dimension of the input-output coupling means are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency, and the dimension is set to Of the reflection characteristics of the high-frequency filter obtained by using the above, select a frequency with a larger reflection than that of an ideal Chebyshev-type filter, A high frequency filter, characterized in that the resonator length of the resonator, the dimensions of the inter-resonator coupling means, and the dimensions of the input / output coupling means are determined so that the reflection becomes equal to or less than a predetermined magnitude at the wave number. 7. A waveguide type high frequency filter comprising a plurality of cavity resonators each comprising a waveguide and a coupling means for coupling the cavity resonators and a susceptance element as an input / output coupling means. A plurality of zero points of the Chebyshev function as a function of the in-tube wavelength of the waveguide are set in the pass band of the wave tube type high frequency filter, and a frequency corresponding to the in-tube wavelength of the plurality of zero points is defined as a reflection zero frequency. A high-frequency filter characterized in that the resonator length of the resonator, the value of the susceptance element, and the dimension of the susceptance element are determined so that the reflection becomes minimum at the reflection zero frequency. 8. A waveguide type high frequency filter comprising a plurality of cavity resonators each comprising a waveguide and a susceptance element as a coupling means for the cavity resonators and an input / output coupling means. A plurality of zero points of the Chebyshev function as a function of the in-tube wavelength of the waveguide are set in the pass band of the wave tube type high frequency filter, and a frequency corresponding to the in-tube wavelength of the plurality of zero points is defined as a reflection zero frequency. , The resonator length of the resonator, the value of the susceptance element, and the dimensions of the susceptance element are determined so that the reflection is minimized at the reflection zero frequency, and the high-frequency wave of the waveguide type obtained by using the dimensions is determined. Of the reflection characteristics of the filter,
A frequency with a large reflection is selected based on the characteristics of an ideal Chebyshev filter, and the resonator length of the resonator and the susceptance element value are set so that the reflection becomes a predetermined value or less at the large reflection frequency and the zero reflection frequency. And a dimension of the susceptance element is determined. 9. A waveguide type high frequency filter comprising a plurality of cavity resonators each comprising a waveguide and coupling means for coupling said cavity resonators and a susceptance element as an input / output coupling means. Multiple maximum points of the Chebyshev function as a function of the waveguide wavelength of the waveguide are set in the pass band of the wave tube type high frequency filter, and the frequency corresponding to the waveguide wavelength of the plurality of maximum points is set as the reflection maximum frequency. A high-frequency filter characterized in that the resonator length of the resonator, the susceptance element value, and the dimensions of the susceptance element are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency. 10. A waveguide type high frequency filter comprising a plurality of cavity resonators each comprising a waveguide and a coupling means for coupling the cavity resonators and a susceptance element as an input / output coupling means. Multiple maximum points of the Chebyshev function as a function of the waveguide wavelength of the waveguide are set in the pass band of the wave tube type high frequency filter, and the frequency corresponding to the waveguide wavelength of the plurality of maximum points is set as the reflection maximum frequency. The resonator length of the resonator, the susceptance element value, and the dimensions of the susceptance element are determined so that the reflection has a predetermined maximum value at the reflection maximum frequency. Of the reflection characteristics of the wave tube type high-frequency filter, select a frequency with a larger reflection than the ideal Chebyshev type filter, and A high frequency filter characterized in that the resonator length of the resonator, the value of the susceptance element, and the dimension of the susceptance element are determined so that the reflection becomes equal to or less than a predetermined magnitude at the maximum emission frequency. 11. The susceptance element is an inductive iris or an inductive post.
10. The high frequency filter according to any one of 10. 12. When the number of resonators is N and the susceptance value of the i-th susceptance element determined from the equivalent circuit element value at the center frequency of the filter is B0i, the susceptance value Bi of the i-th susceptance element is The range set according to the formula is set.
The high frequency filter according to any one of 1. 1 <Bi / B0i <1.2 (1 ≦ i ≦ 0.2N, N ≦ i ≦ N + 1) 0.8 <Bi / B0i <1 (0.2N <i ≦ 0.4, 0.8N ≦ i < N) 0.9 <Bi / B0i ≦ 1 (0.4N <i <0.8N) 13. An impedance transformer comprising a plurality of transmission lines of about ¼ wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line, wherein the transmission is performed. Select a frequency that is equal to or greater than the number of parameters that determine the line length and the characteristic impedance of the line, and that the transmission characteristic or the reflection characteristic of the impedance transformer approaches the desired value at the selected frequency. An impedance transformer characterized in that the line length and the characteristic impedance are determined. 14. An impedance transformer comprising a plurality of transmission lines of about ¼ wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line, wherein the impedance transformer comprises: Within the pass band of the transformer, a plurality of slope zeros of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set, and the frequency corresponding to the plurality of slope zeros is defined as a reflection zero frequency or a reflection maximum frequency, An impedance transformer characterized in that the line length and the characteristic impedance of the transmission line are determined so that the reflection has a minimum value or a predetermined maximum value at the reflection zero frequency or the reflection maximum frequency. 15. An impedance transformer comprising a plurality of transmission lines of about ¼ wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line. Within the pass band of the transformer, set multiple zero points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line,
An impedance transformer characterized in that a frequency corresponding to the plurality of zero points is defined as a reflection zero frequency, and a line length and a characteristic impedance of the transmission line are determined so that reflection is minimized at the reflection zero frequency. 16. An impedance transformer comprising a plurality of transmission lines of about ¼ wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and an input / output line. Within the pass band of the transformer, set multiple zero points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line,
The frequency corresponding to the plurality of zeros is defined as a reflection zero frequency, and the line length of the transmission line and the characteristic impedance are determined so that the reflection has a minimum at the reflection zero frequency, and the size is obtained by using the above dimensions. Of the reflection characteristics of the impedance transformer, select a frequency with a larger reflection than the characteristics of an ideal Chebyshev transformer, and perform the above-mentioned transmission so that the reflection becomes a predetermined magnitude or less at the frequency of the above reflection and the reflection zero frequency. An impedance transformer characterized in that the line length of the line and the characteristic impedance are determined. 17. An impedance transformer comprising a plurality of transmission lines of about ¼ wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line, wherein the impedance transformer comprises: Multiple maximum points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set in the pass band of the transformer, and the frequency corresponding to the plurality of maximum points is specified as the reflection maximum frequency. In the impedance transformer, the line length and the characteristic impedance of the transmission line are determined so that the reflection has a predetermined maximum value. 18. An impedance transformer comprising a plurality of transmission lines of about 1/4 wavelength, an impedance step between the transmission lines, and an impedance step between the transmission line and the input / output line, wherein the impedance transformer comprises: Multiple maximum points of the Chebyshev function as a function of the frequency of the radio wave in the transmission line are set in the pass band of the transformer, the frequencies corresponding to the multiple maximum points are specified as the reflection maximum frequencies, and the reflection maximum frequencies are set. In the reflection characteristics of the impedance transformer obtained by determining the line length of the transmission line and the characteristic impedance so that the reflection has a predetermined maximum value in, and using the above dimensions, the ideal Chebyshev transformer Select a frequency with large reflection based on the characteristics, and reflect at the frequency with large reflection and the maximum frequency with reflection. An impedance transformer characterized in that the line length and the characteristic impedance of the transmission line are determined so that the transmission line has a predetermined size or less. 19. A plurality of substantially quarter wavelength waveguides and steps in the height direction or width direction between the waveguides, and a height direction between the waveguides and the input / output waveguides. Alternatively, in a waveguide type impedance transformer having steps in the width direction, a plurality of zero points of the Chebyshev function as a function of the waveguide wavelength of the waveguide are set in the pass band of the impedance transformer, The frequency corresponding to the in-tube wavelength of the zero point of is defined as the reflection zero frequency, and the axial length and height or width of the waveguide are determined so that the reflection is minimized at the reflection zero frequency. And an impedance transformer. 20. A plurality of substantially quarter wavelength waveguides and steps in a height direction or a width direction between the waveguides, and a height direction between the waveguides and the input / output waveguides. Alternatively, in a waveguide type impedance transformer having steps in the width direction, a plurality of zero points of the Chebyshev function as a function of the waveguide wavelength of the waveguide are set in the pass band of the impedance transformer, The frequency corresponding to the in-tube wavelength of the zero point is defined as the reflection zero frequency, and the axial length and height or width of the waveguide are determined so that the reflection is minimized at the reflection zero frequency. Among the reflection characteristics of the above-mentioned waveguide type impedance transformer obtained by using, a frequency with a larger reflection is selected than the characteristic of an ideal Chebyshev type transformer, and the frequency of the above reflection and the zero frequency of the reflection are selected. In the impedance transformer, the axial length and height or width of the waveguide are determined so that the reflection becomes equal to or less than a predetermined value. 21. A plurality of substantially quarter wavelength waveguides and steps in a height direction or a width direction between the waveguides, and a height direction between the waveguides and the input / output waveguides. Alternatively, in a waveguide type impedance transformer having a step in the width direction, a plurality of local maximum points of the Chebyshev function as a function of the waveguide wavelength of the waveguide are set in the passband of the impedance transformer, The frequency corresponding to the in-tube wavelength of a plurality of maximum points is defined as the reflection maximum frequency, and the axial length of the waveguide and the height or width are set so that the reflection has a predetermined maximum value at the reflection maximum frequency. Impedance transformer characterized by the decision. 22. A plurality of substantially quarter wavelength waveguides and steps in a height direction or a width direction between the waveguides, and a height direction between the waveguides and the input / output waveguides. Alternatively, in a waveguide type impedance transformer having a step in the width direction, a plurality of local maximum points of the Chebyshev function as a function of the waveguide wavelength of the waveguide are set in the passband of the impedance transformer, The frequency corresponding to the in-tube wavelength of a plurality of maximum points is defined as the reflection maximum frequency, and the axial length of the waveguide and the height or width are set so that the reflection has a predetermined maximum value at the reflection maximum frequency. Decide,
Among the reflection characteristics of the waveguide type impedance transformer obtained by using the above dimensions, a frequency with a larger reflection than the characteristic of an ideal Chebyshev transformer is selected, and at the large frequency of the reflection and the maximum reflection frequency. An impedance transformer characterized in that the axial length and the height or width of the waveguide are determined so that the reflection becomes equal to or less than a predetermined magnitude.