JP2008244706A - Filter and high frequency module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter and a high frequency module which can obtain good band characteristics in a microwave or a millimeter wave, moreover, have high flexibility in design, and are small-sized and low cost. <P>SOLUTION: The filter 1 is provided with a dielectric substrate 2, a strip line 3, a plurality of resonator electrodes 4, and a ground electrode 5. The same number of resonator electrodes 4 is prepared in both sides of the strip line 3. The respective resonator electrodes 4 are rectangular shapes, one side ends are open ends 41, and other ends are short-circuit ends 42. Namely, via holes 6 are prepared in lower sides of λg/4 positions 42 from the open ends 41 of the respective resonator electrodes 4 and are connected to the positions 42 and the ground terminal 5 simultaneously. Directions of the resonator electrodes 4 are established to be perpendicular to a length direction of the strip line 3, and the open ends 41 of the resonator electrodes 4 of the both sides of the strip line 3 are established to face each other. Moreover, spaces of adjacent resonator electrodes 4 are established to be λg/4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a filter and a high frequency module applied to a high frequency circuit.

Conventionally, as this type of filter, an open stub-shaped resonator electrode having a length of a quarter of the wavelength at the center frequency in the band is projected from the strip line at an interval of a quarter of the wavelength. Alternatively, there is one in which the stripline is bent within an interval of a quarter of the wavelength to reduce the size (for example, see Patent Document 1). There is also a filter in which circular or polygonal resonator electrodes are arranged on both sides of a strip line and the center of each resonator electrode is grounded (see, for example, Patent Document 2).
However, in the above filter having an open stub-shaped resonator electrode, adjacent resonator electrodes are likely to be electric field coupled. Therefore, in a filter in which the distance between adjacent resonator electrodes is narrowed for use in microwaves and millimeter waves, strong electric field coupling occurs, and good band characteristics cannot be obtained. And since a filter must be designed in consideration of such electric field coupling, the problem that design freedom falls arises.
Further, in the above-described filter in which the stripline is bent within an interval of ¼ of the wavelength, although the electric field coupling between the resonator electrodes can be weakened, the stripline is ¼ of the wavelength of microwave or millimeter wave. In order to bend and form within one interval, a highly accurate fine wiring process is required, and there is a problem that manufacturing equipment costs are increased accordingly.

Therefore, resonator electrodes, one of which is an open end and the other is a short-circuited end, are arranged on both sides of the stripline at intervals of a quarter of the wavelength at the center frequency in the band, and the resonance direction of the stripline is A filter parallel to the length direction has been proposed (see, for example, Patent Document 3 and Patent Document 4).
In such a filter, since the open end and the short-circuit end of the adjacent resonator electrodes face each other, almost no electric field coupling occurs, and good band characteristics can be obtained.

By the way, in a filter used with a microwave or millimeter wave with a short wavelength, the reactance value between the strip line and the resonator electrode often deviates from a desired reactance value at the time of manufacture. For this reason, a filter having a structure capable of changing the reactance value after manufacturing the stripline and the resonator electrode is required.
As such a filter, a variable capacitance element is arranged between the strip line and the resonator electrode, and a voltage is applied to the variable capacitance element to change the capacitance value, thereby changing the capacitance between the strip line and the resonator electrode. A wire which connects a lumped constant type capacitor provided on a short-circuited resonator electrode and a strip line with a wire that changes a reactance value (see, for example, Patent Document 5 and Patent Document 6), and the length of the wire In some cases, the reactance value between the strip line and the resonator electrode is changed by adjusting the value (see, for example, Patent Document 7).

JP-A-10-215102 JP 2001-111303 A International Publication No. 2005/013411 Pamphlet JP-A-62-014804 JP 2002-009573 A JP-T-2004-524770 Japanese Patent Laid-Open No. 63-070601

However, the conventional techniques described above have the following problems.
First, as in the filters disclosed in Patent Documents 3 and 4, resonator electrodes having one end as an open end and the other as a short-circuit end are stripped at an interval of a quarter of the wavelength at the center frequency in the band. In the case of a structure that is arranged on both sides of the line and the resonance direction is parallel to the length direction of the strip line, the resonance direction faces the length direction of the strip line. As a result, there is a problem that the size of the filter is increased.
Further, as in the filters disclosed in Patent Document 5 and Patent Document 6, by changing the capacitance value by applying a voltage to the variable capacitance element, the reactance value between the stripline and the resonator electrode is changed. Since an expensive component called a variable capacitance element is required, and a separate power supply device for applying a voltage to the variable capacitance element is required, the manufacturing cost of the filter becomes very high.
Further, in the case of a structure in which a lumped-constant capacitor provided on a resonator electrode and a strip line are connected by a wire as in the filter disclosed in Patent Document 7, a lumped-constant capacitor is required. This increases the product cost. In addition, it is indispensable to solder a lumped capacitor to the desired location of the resonator electrode, and then connect the wires from there. Therefore, the number of manufacturing steps increases, and the manufacturing cost increases accordingly. There is.

  The present invention has been made to solve the above-described problems. In the microwave and millimeter wave, it is possible to obtain good band characteristics, and has a high degree of design freedom, and is small and low cost. An object is to provide a filter and a high-frequency module.

In order to solve the above problems, the invention of claim 1 is directed to a substrate, a strip line for signal input / output provided on the surface of the substrate, and each of which is about a quarter of the wavelength at the center frequency in the band. A plurality of resonator electrodes arranged at intervals of about one-quarter of the wavelength on both sides of the stripline, with one end being an open end and the other end being a short-circuited end The length direction of the resonator electrode from the open end to the short-circuited end with respect to the length direction of the strip line with the open end of each resonator electrode close to the strip line The configuration is such that the open ends of the resonator electrode on one side and the resonator electrode on the other side of the stripline are opposed to each other.
With this configuration, when a signal having an out-of-band frequency is input to the strip line, the signal is not coupled to the plurality of resonator electrodes, and thus propagates to the output end side of the strip line. When an in-band frequency signal is input to the strip line, this signal resonates at the first-stage resonator electrode and is reflected as it is to the input end side of the strip line. That is, the filter of the present invention functions as a band rejection filter that blocks signals in the band centered on the resonance frequency of the resonator electrode and passes signals outside the band.
At this time, since the other end of the resonator electrode is a short-circuited end, electric field coupling between adjacent resonator electrodes hardly occurs.

According to a second aspect of the present invention, in the filter according to the first aspect, the width of a portion of the stripline where the open ends of the resonator electrodes are opposed to each other is widened or narrowed, so that the characteristics of the portion can be obtained. The impedance is adjusted.
With this configuration, the strip line and the resonator electrode can be matched.

According to a third aspect of the present invention, in the filter according to the first aspect, the resonator electrode is changed by changing the length of the open end of each resonator electrode and the opposing length of the side of the strip line facing the end. And the strip line are adjusted in capacity.
With this configuration, the strength of electric field coupling between the stripline and the resonator electrode can be adjusted.

  According to a fourth aspect of the present invention, in the filter according to the first or second aspect, a plurality of resonator electrodes are formed inside the substrate.

The invention according to claim 5 is a substrate, a strip line for signal input / output provided on the surface of the substrate, each set to a length of about one quarter of the wavelength at the center frequency in the band, and at least A filter comprising a plurality of resonator electrodes arranged at intervals of about a quarter of a wavelength on only one side or both sides of a strip line with one end being a short-circuit end, The length direction is set to be perpendicular to the length direction of the strip line, and a wire or an air bridge is directly connected between the strip line and any or all of the plurality of resonator electrodes.
With this configuration, when an out-of-band frequency signal is input to the strip line, this signal is blocked by the resonator electrode connected to the strip line by a wire or an air bridge, and reflected directly to the input end side of the strip line. The When an in-band frequency signal is input to the strip line, it resonates at this resonator electrode and propagates to the resonator electrode side of the next stage or the output end side of the strip line. Therefore, in the filter of the present invention, the band characteristics of the filter can be arbitrarily set by specifying the number and position of the resonator electrodes connected by wires or air bridges. Furthermore, by changing the number or length of wires or air bridges connected to each resonator electrode, the reactance value between the resonator electrode and the strip line can be adjusted, and the filter characteristics can be set more finely. .
That is, the filter of the present invention can function as a reactance variable band-pass filter.

  A sixth aspect of the present invention is the filter according to the fifth aspect, wherein a plurality of resonator electrodes are arranged on both sides of the strip line, and a wire or an air bridge is located on one side of the strip line. It is set as the structure connected directly between all and stripline.

  According to a seventh aspect of the present invention, in the filter according to any one of the first to sixth aspects, the strip line constitutes a microstrip line together with a ground electrode provided on the back surface or inside of the substrate.

  The invention of claim 8 is the filter according to any one of claims 1 to 7, wherein the substrate is a dielectric substrate.

  According to a ninth aspect of the present invention, in the filter according to any one of the first to seventh aspects, the substrate is a semiconductor substrate.

  A tenth aspect of the present invention is the filter according to the ninth aspect, wherein the semiconductor substrate is a gallium arsenide substrate or a silicon substrate.

  A high-frequency module according to an eleventh aspect of the present invention includes the filter according to any one of the first to tenth aspects.

  As described in detail above, according to the filters of the first to fourth aspects of the present invention, the electric field coupling between the adjacent resonator electrodes hardly occurs, so that a good band characteristic with respect to microwaves and millimeter waves is obtained. It can be made to function as the band-reject filter that it has. In addition, it is not necessary to design a filter in consideration of this electric field coupling, so that the degree of freedom in design can be increased. Further, since the direction of each resonator electrode is set to be perpendicular to the strip line and the interval between the resonator electrodes is set to an interval of about ¼ of the wavelength at the center frequency in the band, the length of the strip line is set. The direction dimension can be shortened, and the filter can be reduced in size accordingly.

  Further, according to the filter of the inventions of claims 5 and 6, the number and position of the resonator electrodes connected by the wire or air bridge, the number of wires or air bridges connected to each resonator electrode, By specifying the length, it is possible to function as a variable reactance band-pass filter capable of adjusting the filter characteristics. In addition, the reactance of each resonator electrode can be changed simply by changing the number or length of the wires or air bridges, so that an expensive variable capacitance element or its driving power supply device is not required, and the number of parts can be reduced. A filter with a small reactance variable can be realized. As a result, manufacturing of such a filter and reduction of product cost can be achieved.

  In addition, according to the high frequency module of the invention of claim 11, since the filter is provided, good band characteristics and a high degree of design freedom can be obtained in microwaves and millimeter waves. Cost reduction is possible.

  The best mode of the present invention will be described below with reference to the drawings.

  1 is a partially cutaway perspective view showing a filter according to a first embodiment of the present invention, FIG. 2 is a plan view of the filter, and FIG. 3 is a cross-sectional view taken along line AA in FIG. FIG.

As shown in FIG. 1, the filter 1 of this embodiment includes a dielectric substrate 2, a strip line 3, 14 resonator electrodes 4, and a ground electrode 5.
The dielectric substrate 2 is a plate-like body formed of a dielectric material having a predetermined relative dielectric constant, and the strip line 3 is patterned on the surface 2 a of the dielectric substrate 2.
The strip line 3 is a line disposed substantially at the center of the surface 2a of the dielectric substrate 2 in order to input and output signals, and is a linear conductor pattern having a width “W”.

The resonator electrode 4 is a conductor pattern shorter than the strip line 3, and seven pieces are arranged on both sides of the strip line 3 as shown in FIG. 2.
FIG. 4 is a partially enlarged plan view for explaining the dimensions and orientations of the resonator electrodes 4 and the spacing between the resonator electrodes 4.
As shown in FIG. 4, the resonator electrodes 4 (4A) and 4 (4B) located on both sides of the strip line 3 having a width W form a pair.
Each resonator electrode 4 (4A, 4B) has a rectangular shape with a length of “L” and a width of “w”, one end being an open end 41 and the other end being a short-circuited end.
Specifically, the via hole 6 is provided below the portion 42 having a length L1 from the open end 41 of each resonator electrode 4 (4A, 4B), and the upper end of the via hole 6 is connected to the portion 42 and the lower end. Is connected to a ground electrode 5 described later. Then, the length L1 from the open end 41 to the part 42, that is, the length from the open end 41 to the short-circuited end 42 is set to a wavelength at the center frequency within the band of each resonator electrode 4 (4A, 4B) (hereinafter, “ λg ”))). Further, the open end 41 was brought close to the strip line 3 until the distance D1, and the short-circuit end 42 was moved away from the strip line 3. That is, the length direction of each resonator electrode 4 (4A, 4B) from the open end 41 to the short-circuit end 42 was set to be perpendicular to the length direction of the stripline 3. The open ends 41 and 41 of the resonator electrode 4 (4A) on one side and the resonator electrode 4 (4B) on the other side of the stripline 3 were set to face each other. Therefore, the resonator electrodes 4 (4A) and 4 (4B) oriented in a direction perpendicular to the stripline 3 form a pair on both sides of the stripline 3 with the open ends 41 and 41 facing each other. Further, the interval D between the adjacent resonator electrodes 4 (4A) or between the resonator electrodes 4 (4B) was set to λg / 4. As a result, the filter 1 of this embodiment has a structure in which resonators having a length of λg / 2 constituted by the resonator electrodes 4A and 4B are incorporated in the strip line 3 at intervals of 7 pairs and λg / 4.

  As shown in FIGS. 1 and 3, the ground electrode 5 is provided on the back surface 2 b of the dielectric substrate 2, whereby the strip line 3 forms a microstrip line together with the ground electrode 5. Needless to say, the ground electrode 5 may be provided not on the back surface 2 b of the dielectric substrate 2 but inside.

Next, the operation and effect exhibited by the filter 1 of this embodiment will be described.
FIG. 5 is a plan view for explaining the function and effect of the filter, and FIG. 6 is a schematic sectional view for explaining electric field coupling between each resonator electrode 4 (4A, 4B) and the stripline 3. is there.
As shown in FIG. 5, when a signal S ′ having an out-of-band frequency is input to the strip line 3 from the input end 31, this signal S ′ is supplied to the first-stage resonator electrodes 4A and 4B (the leftmost resonator electrode in the figure). 4A, 4B), and propagates directly to the next-stage resonator electrodes 4A, 4B or the output end 32 side of the stripline 3. When a signal S in the frequency band centered on the in-band frequency, that is, the resonance frequency of the resonator electrodes 4A and 4B, is input to the stripline 3, the signal S resonates at the resonator electrodes 4A and 4B at each stage. The light is reflected as it is to the input end 31 side of the stripline 3. That is, the filter 1 of this embodiment functions as a band rejection filter that blocks the signal S in the band centered on the resonance frequency of the pair of resonator electrodes 4A and 4B and passes the signal S ′ outside the band.

By the way, at the time of resonance of the resonator electrodes 4A and 4B, only the narrow open end 41 of each resonator electrode 4 (4A and 4B) is opposed to the strip line 3, and therefore each resonator electrode 4 ( The electric field coupling between 4A, 4B) and the stripline 3 may not be as strong as expected. However, in this embodiment, the tip of each resonator electrode 4 (4A, 4B) forms a short-circuited end 42, and the end close to the stripline 3 forms an open end 41. For this reason, as shown in FIG. 6, the electric field E is distributed so as to be weakest at the short-circuit end 42 and strongest at the open end 41.
Since the resonator composed of the paired resonator electrodes 4A and 4B of λg / 2 resonates with the stripline 3 positioned in the gap between the open ends 41 and 41 virtually cut, the electric field distribution However, it is concentrated between the strip line 3 and the open ends 41 and 41, and the resonator electrodes 4A and 4B and the strip line 3 are coupled with a very strong electric field coupling force.

Further, since the interval D between the adjacent resonator electrodes 4 (4A) or between the resonator electrodes 4 (4B) is set to a very narrow interval of λg / 4, the resonator electrodes 4 (4A) or resonance There is a risk of electric field coupling between the device electrodes 4 (4B). However, since the tip of each resonator electrode 4 (4A, 4B) is a short-circuited end 42 and the open end 41 is close to the stripline 3, the resonator electrodes 4 (4A) or resonator electrodes 4 ( 4B) If the distance D between each other is λg / 4, it is considered that electric field coupling does not occur even when microwaves or millimeter waves are used.
FIG. 7 is a diagram showing a coupling coefficient between adjacent resonator electrodes 4 (4A or 4B).
The inventor performed the following simulation in order to confirm the assumption.
The relative dielectric constant of the dielectric substrate 2 is “8.8”, the width W of the strip line 3 (see FIG. 4) is “0.22 mm”, and the length L and width w of each resonator electrode 4 (4A, 4B). Were set to “0.4 mm” and “0.2 mm”, and the distance D1 between each resonator electrode 4 (4A, 4B) and the strip line 3 was set to “0.1 mm”. Then, when a 60 GHz signal is input to the strip line 3 and the coupling coefficient at each interval D is calculated while changing the interval D between adjacent resonator electrodes 4 (4A or 4B) from 0.01 mm to 1 mm, Results were obtained as shown in FIG.
That is, as shown by the coupling coefficient curve K in FIG. 7, when the distance D between adjacent resonator electrodes 4 (4A or 4B) is 0.1 mm or more, the coupling coefficient is “0”, and the resonance It can be seen that electric field coupling between the electrode electrodes 4 (4A or 4B) does not occur.
Therefore, as long as the filter 1 of this embodiment in which the distance D between adjacent resonator electrodes 4 (4A or 4B) is set to λg / 4 at 60 GHz is used, the electric field coupling between the resonator electrodes 4 (4A or 4B). Hardly occurs.

  As described above, according to the filter 1 of this embodiment, very strong electric field coupling occurs between the resonator electrode 4 and the strip line 3, and the electric field coupling between the adjacent resonator electrodes 4 almost occurs. Therefore, it functions as a band rejection filter having good band characteristics with respect to microwaves and millimeter waves. Therefore, it is not necessary to design the filter 1 in consideration of electric field coupling between the resonator electrodes 4, so that the degree of freedom in design can be increased, and the resonator electrodes 4 perpendicular to the strip line 3 are arranged side by side. Since it can arrange in the space | interval of the space | interval D, the dimension of the length direction of the stripline 3 of the filter 1 can be shortened.

The inventors conducted the following experiment in order to confirm the band characteristics of the filter.
FIG. 8 is a diagram showing band characteristics obtained by actual measurement, and FIG. 9 is a diagram showing band characteristics obtained by simulation.
In this experiment, the dielectric substrate 2 having a relative dielectric constant of “8.8” and a thickness of 0.2 mm is used, the width W of the stripline 3 is “0.22 mm”, and each resonator electrode 4 (4A, 4B). ) Of length L and width w of “0.4 mm” and “0.2 mm”, and length L1 from the open end 41 to the short-circuit end 42 of each resonator electrode 4 (4A, 4B) is “0.3 mm”. The distance D1 between each resonator electrode 4 (4A, 4B) and the strip line 3 was set to “0.1 mm”. Then, by sweeping with a signal having a frequency of 0 GHz to 110 GHz and actually measuring the reflection coefficient and the transmission coefficient (dB), a result as shown in FIG. 8 was obtained.
That is, as shown by the reflection coefficient curve S11 in FIG. 8, this filter 1 has a reflection coefficient of almost 0 (dB) at a frequency in the vicinity of 60 GHz, and reflects almost all signals in this band. Yes. Further, as shown by the transmission coefficient curve S21 of FIG. 8, the filter 1 has a transmission coefficient of approximately −40 (dB) at a frequency in the vicinity of 60 GHz, and hardly transmits signals in this band. .
As a result of the above experiment, according to this filter 1, it was confirmed that the signal of the frequency was reliably reflected in the desired band near 60 GHz, and the signal outside the band was surely transmitted.
As a result of the simulation under the same conditions as those described above, the inventors obtained the same results as the actual measurement results as shown in the reflection coefficient curve S11 ′ and the transmission coefficient curve S21 ′ of FIG. Therefore, in the following example, it is assumed that the effect is confirmed using only the simulation, and the same result as the actual measurement is obtained.

Next explained is the second embodiment of the invention.
FIG. 10 is a plan view showing an example of a filter according to the second embodiment of the present invention, and FIG. 11 is a plan view showing another example.
The filter of this embodiment is different from the first embodiment in that the characteristic impedance of a specific part of the stripline 3 is different from the characteristic impedance of other parts.
That is, as shown in FIG. 10, the width W1 of the portion 33 of the stripline 3 where the open ends 41, 41 of the resonator electrodes 4A, 4B face each other is set wider than the width W of the stripline 3, The characteristic impedance of the part 33 is set lower than the characteristic impedance of other parts.
With this configuration, the strip line 3 and the resonator electrodes 4A and 4B can be matched.

Further, as shown in FIG. 11, the width W1 of the portion 33 of the stripline 3 where the open ends 41, 41 of the resonator electrodes 4A, 4B face each other is set to be narrower than the width W of the stripline 3, The characteristic impedance of the part 33 can be made higher than the characteristic impedance of other parts.
Since other configurations, operations, and effects are the same as those in the first embodiment, description thereof is omitted.

Next explained is the third embodiment of the invention.
FIG. 12 is a plan view showing an example of a filter according to the third embodiment of the present invention, and FIG. 13 is a plan view showing another example.
The filter of this embodiment is different from the first and second embodiments in that the electric field coupling between the strip line 3 and each resonator electrode 4 (4A, 4B) can be adjusted.
That is, as shown by a box B1 in FIG. 12, a narrow pad portion 40 is provided on the open end 41 side of each resonator electrode 4 (4A, 4B). As a result, the length of the open end 40a of each resonator electrode 4 (4A, 4B) and the length of the side 30 of the stripline 3 facing this end 40a are set as the first and second embodiments. It can be changed shorter than in the example. As a result, the capacitance value between each resonator electrode 4 (4A, 4B) and the strip line 3 can be reduced, and the electric field coupling force can be weakened.

Further, as shown in FIG. 13, a comb-like projection 30 'is provided on the strip line 3, and a comb-like projection 40' adjacent to the projection 30 'is engaged with each resonator electrode 4 ( 4A, 4B), the capacitance value between each resonator electrode 4 (4A, 4B) and the strip line 3 can be increased to increase the electric field coupling force.
Other configurations, operations, and effects are the same as those in the first and second embodiments, and thus description thereof is omitted.

Next explained is the fourth embodiment of the invention.
FIG. 14 is a sectional view showing a filter according to a fourth embodiment of the present invention.
The filter of this embodiment is different from the first to third embodiments in that a plurality of resonator electrodes 4 (4A, 4B) are formed inside the dielectric substrate 2.
Specifically, as shown in FIG. 14, with the open ends 41 and 41 positioned below the strip line 3, the resonator electrodes 4A and 4B are placed inside the dielectric substrate 2 and on the strip line 3. Place on both sides.
With this configuration, the degree of design freedom can be improved when designing the coupling amount between the strip line 3 and the resonator electrodes 4A and 4B.
Since other configurations, operations, and effects are the same as those in the first to third embodiments, description thereof is omitted.

Next explained is the fifth embodiment of the invention.
15 is a plan view showing a filter 1 according to a fifth embodiment of the present invention, and FIG. 16 is a cross-sectional view taken along the line BB in FIG.
This embodiment is different from the first to third embodiments constituting the band rejection filter in that a wire is connected between the resonator electrode and the strip line to constitute a variable reactance type band transmission filter. .

  Specifically, as shown in FIGS. 15 and 16, the wire 7 was directly connected between the open end 41 of each resonator electrode 4 (4 </ b> A, 4 </ b> B) and the strip line 3. In this embodiment, the wire 7 is connected to all the resonator electrodes 4. That is, since the paired resonator electrodes 4A and 4B and the strip line 3 are electrically connected via the wires 7 and 7, the end portion 41 of each resonator electrode 4 becomes a short-circuited end. Therefore, seven pairs of resonator electrodes 4A and 4B having a length of λg / 2 are directly connected to the strip line 3.

With this configuration, when a signal having an in-band frequency is input to the strip line 3 from the input end 31, the signal resonates at the resonator electrodes 4A and 4B, and the next resonator electrode 4A and 4B side or the strip line 3 is resonated. Is output to the output end 32 side of the output. When a signal having an out-of-band frequency is input to the strip line 3, the signal is blocked by the resonator electrodes 4A and 4B and reflected as it is to the input end 31 side of the strip line 3.
That is, the filter 1 of the present invention functions as a band transmission filter.

Inventors etc. performed the following simulations in order to confirm this effect.
FIG. 17 is a diagram showing band characteristics obtained by simulation.
Dielectric constant and thickness of dielectric substrate 2, width W of strip line 3, length L and width w of each resonator electrode 4 (4A, 4B), open end of each resonator electrode 4 (4A, 4B) The length L1 from 41 to the short-circuit end 42, the distance D1 between each resonator electrode 4 (4A, 4B) and the stripline 3, and the sweep frequency are set in the same manner as in the experiment of the first embodiment, and FIG. When the simulation was performed on the filter shown, the result shown in FIG. 17 was obtained.
That is, as shown by the transmission coefficient curve S21 in FIG. 17, this filter has a transmission coefficient of 0 (dB) in a band of about 50 GHz to 80 GHz, and transmits almost all signals in this band. Further, as shown by the reflection coefficient curve S11 in FIG. 17, this filter has a reflection coefficient of −30 (dB) in the above band, and hardly reflects the signal in this band. On the other hand, as shown by the transmission coefficient curve S21, the transmission coefficient outside the band of about 50 GHz to 80 GHz is a minimum of −40 (dB), and most of the signals outside the band are not transmitted. Further, as shown by the reflection coefficient curve S11, outside the band, the reflection coefficient is almost 0 (dB), and signals outside the band are almost reflected.
From the above simulation, it was confirmed that this filter functions as a transmission filter that transmits signals in a band of about 50 GHz to 80 GHz.

This simulation was performed for a filter in which the wires 7 were connected between all the resonator electrodes 4 and the strip lines 3. However, by changing the number and position of the resonator electrodes 4 connected by the wires 7 and the number and length of the wires 7 connected to each resonator electrode 4, characteristics different from those of the simulation can be obtained. It is. Therefore, it is considered that the characteristics of the filter can be adjusted by changing these conditions.
Therefore, the inventors performed various simulations in order to confirm the difference in band characteristics depending on the number of wires 7 and the like.

First, the band characteristics depending on the number of pairs of resonator electrodes 4A and 4B to which the wire 7 is connected are simulated.
18 is a plan view of a filter having five pairs of resonator electrodes 4A and 4B to which wires 7 are connected, and FIG. 19 is a diagram showing a simulation result of the filter of FIG. 20 is a plan view of a filter having a pair of resonator electrodes 4A and 4B to which wires 7 are connected, and FIG. 21 is a diagram showing a simulation result of the filter of FIG.
First, as shown in FIG. 18, the wire 7 is removed from the pair of resonator electrodes 4A and 4B at the first stage and the last stage, and five pairs of resonator electrodes 4A and 4B to which the wire 7 is connected are used in the same manner as described above. As a result of simulation, results as shown in FIG. 19 were obtained.
That is, as shown by the transmission coefficient curve S21 and the reflection coefficient curve S11 in FIG. 19, the transmission coefficient decreased and the reflection coefficient increased in a narrow band near about 60 GHz. In other bands, the results are almost the same as those shown in FIG.
Next, as shown in FIG. 20, a simulation similar to the above was performed with only one pair of the resonator electrodes 4A and 4B to which the wire 7 was connected, and the result shown in FIG. 21 was obtained. .
As shown by the transmission coefficient curve S21 and the reflection coefficient curve S11 in FIG. 21, in the band around about 60 GHz, the transmission coefficient was greatly reduced and the reflection coefficient was also greatly increased. That is, by reducing the number of resonator electrodes 4A and 4B to which the wire 7 is connected, the wire 7 approaches the band characteristic of a filter having no wire (see FIGS. 8 and 9) and functions as a band rejection filter. It was confirmed that

Next, the band characteristics when the wire 7 is connected to only one of the pair of resonator electrodes 4A and 4B were simulated.
22 is a plan view of a filter in which the wire 7 is connected only to the resonator electrode 4B on one side of the stripline 3, and FIG. 23 is a diagram showing a simulation result of the filter of FIG. FIG. 24 is a plan view of a filter in which the wires 7 are alternately connected to the resonator electrodes 4A and 4B on both sides of the strip line 3. FIG. 25 is a diagram showing the simulation results of the filter of FIG. is there.
As shown in FIG. 22, when a simulation was performed on a filter in which the wire 7 was connected only to the resonator electrode 4B on one side of the stripline 3, the result shown in FIG. 23 was obtained.
That is, as shown by the transmission coefficient curve S21 and the reflection coefficient curve S11 in FIG. 23, the transmission coefficient is high and the reflection coefficient is low in a band of about 40 GHz or more. In particular, in the band of about 40 GHz to 60 GHz, the transmission coefficient and the reflection coefficient are constant, and can be used as a band transmission filter for this band.
Next, as shown in FIG. 24, a simulation was performed on a filter in which the wires 7 were alternately connected to the resonator electrodes 4A and 4B on both sides of the stripline 3. As shown in FIG. The result was obtained.
From the above, when the wire 7 is connected to only one of the pair of resonator electrodes 4A and 4B, the band characteristics are substantially the same as long as the wire 7 is connected to one of the resonator electrodes 4A and 4B. These filters were confirmed to function as good band-pass filters.

Furthermore, the band characteristics of a filter in which two wires 7 are connected to each resonator electrode 4 (4A, 4B) were simulated.
26 is a plan view of a filter in which two wires 7 are connected to each resonator electrode 4, and FIG. 27 is a diagram showing a simulation result of the filter of FIG.
As shown in FIG. 26, a simulation was performed on a filter in which two wires 7 were connected to the open ends 41 of the resonator electrodes 4 (4A, 4B), and the results shown in FIG. 27 were obtained.
As shown by the transmission coefficient curve S21 and the reflection coefficient curve S11 in FIG. 27, the transmission coefficient is high and the reflection coefficient is low in a band of about 40 GHz to 80 GHz. In addition, the transmission coefficient curve S21 and the reflection coefficient curve S11 shown in FIG.
From these results, when the wires 7 are connected to the open ends 41 of all the resonator electrodes 4 (4A, 4B), the band characteristics are almost the same regardless of the number of the wires 7, and these filters Can be estimated to function as a good band-pass filter.

Finally, the band characteristics of the filter in which the wire 7 is connected to the short-circuit end 42 of each resonator electrode 4 were simulated.
FIG. 28 is a plan view of a filter in which the wire 7 is connected to the short-circuit end 42 of each resonator electrode 4 (4A, 4B), and FIG. 29 is a diagram showing a simulation result of the filter of FIG.
As shown in FIG. 28, when the length of the wire 7 was increased and a simulation was performed on a filter in which one end 71 of the wire 7 was connected to the short-circuited end 42 of each resonator electrode 4 (4A, 4B). The result as shown in FIG. 29 was obtained.
As shown by the transmission coefficient curve S21 in FIG. 29, the transmission coefficient is almost 0 (dB) in all bands of about 40 GHz or more, and the reflection coefficient is −− in this band as shown by the reflection coefficient curve S11. 10 (dB) or less, and it was confirmed that this filter functions as a very good band transmission filter in a band of about 40 GHz or more.

  From the above simulation, the band characteristics of the filter can be adjusted by changing the number and position of the resonator electrodes 4 connected by the wires 7 and the number and length of the wires 7 connected to each resonator electrode 4. Turned out to be possible.

  In addition, since the reactance of each resonator electrode 4 can be changed only by changing the number and length of the wires 7, an expensive variable capacitance element, a power supply device for driving the same are not required, and the number of parts is small. A variable reactance type filter can be realized. As a result, it is possible to reduce the manufacturing cost and product cost of the filter 1.

In the fifth embodiment, as a filter in which the wire 7 is directly connected between the strip line 3 and any or all of the plurality of resonator electrodes 4, FIGS. 15, 18, 20, 22, Although the filters shown in FIGS. 24, 26, and 28 have been illustrated, the present invention is not limited to these filters. For example, the filters shown in FIGS. 30 to 37 also connect the wire 7 to the strip line 3 and a plurality of resonances. Variations of the filter directly connected between any or all of the electrode electrodes 4 are included within the scope of such filters.
FIG. 30 is a plan view of a filter according to a first modification of the fifth embodiment, and FIG. 31 is a cross-sectional view taken along the line CC in FIG.
As shown in FIGS. 30 and 31, the filter has a configuration in which one end 71 of the wire 7 is connected to the central portion 43 of each resonator electrode 4 (4A, 4B).
32 is a plan view of a filter according to a second modification, FIG. 33 is a sectional view taken along the line DD in FIG. 32, and FIG. 34 is a plan view of a filter according to the third modification. FIG. 35 is a plan view of a filter according to a fourth modification.
In the filter of the above embodiment, the via hole 6 connected to the ground electrode 5 is provided below the portion 42 having a length L1 from the open end 41 of each resonator electrode 4 (4A, 4B), and this portion is short-circuited. The edge 42 was used.
However, in the filters shown in FIGS. 32 to 35, the via hole 6 is provided below the one end 41, and this portion is a short-circuit end 41, and the portion 42 having a length L1 from the short-circuit end 41 is an open end. Is made.
Specifically, in the filter shown in FIGS. 32 and 33, one end 71 of the wire 7 is connected to the tanged end 41 of each resonator electrode 4 (4A, 4B). In the filter shown in FIG. 7 is connected to the central portion 43 of each resonator electrode 4 (4A, 4B). In FIG. 35, one end 71 of the wire 7 is connected to the open end of each resonator electrode 4 (4A, 4B). 42 is connected.
36 is a plan view of a filter according to a fifth modification of the fifth embodiment, and FIG. 37 is a cross-sectional view taken along line EE in FIG.
In this filter, as shown in FIGS. 36 and 37, via holes 6 are provided at both ends of each resonator electrode 4 (4A, 4B), and both ends are short-circuited ends 41, 42, and one end 71 of the wire 7 is provided. Is connected to the short-circuit end 41.
Other configurations, operations, and effects are the same as those in the first to fourth embodiments, and thus description thereof is omitted.

Next explained is the sixth embodiment of the invention.
FIG. 38 is a block diagram showing a high-frequency module according to the sixth embodiment of the present invention.
As shown in FIG. 38, the high-frequency module 8 of this embodiment is configured by combining an antenna block 81, a duplexer block 82, a transmission block 83, a reception block 84, and an oscillation block 85.

The antenna block 81 is a block that transmits a transmission radio wave and receives a reception radio wave, and includes an antenna 81a. The duplexer block 82 is a block for switching the antenna 81a to the transmission state or the reception state by the duplexer 82a. The transmission block 83 is a block that is connected to the duplexer block 82 and outputs a high-frequency signal toward the antenna block 81, and includes a mixer 83a, a filter 83b, and a power amplifier 83c. On the other hand, the reception block 84 is a block that is connected to the duplexer block 82 and receives a high-frequency signal received by the antenna block 81, and includes a low noise amplifier 84a, a filter 84b, and a mixer 84c. The oscillation block 85 is connected to the transmission block 83 and the reception block 84, and oscillates a local oscillation signal LO having a predetermined frequency from the local oscillator 85a to the mixers 83a and 84c.
With this configuration, the intermediate frequency signal IF modulated in the baseband unit (not shown) is input to the high frequency module 8 via the input terminal 83A, up-converted to a high frequency signal by the transmission block 83, and transmitted as a radio wave from the antenna 81a. The The intermediate frequency signal IF received by the antenna 81a and down-converted by the reception block 84 is output from the output terminal 84A to a baseband unit (not shown) and demodulated by the baseband unit.

In the high-frequency module 8, any one of the filters of the first to fifth embodiments is applied as the filters 83b and 84b, and is installed in the local oscillator 85a.
As a result, it is possible to obtain a high-frequency module that can obtain good band characteristics and a high degree of design freedom in microwaves and millimeter waves, and that can be reduced in size and cost.
Other configurations, operations, and effects are the same as those in the first to fifth embodiments, and thus description thereof is omitted.

In addition, this invention is not limited to the said Example, A various deformation | transformation and change are possible within the range of the summary of invention.
In the said Example, although the example which formed the shape of the resonator electrode 4 in the rectangular shape was shown, the shape of the resonator electrode 4 is not limited to this. For example, an ellipse or a circle as shown in FIG. 39 (a), a trapezoid as shown in FIG. 39 (b), and a rectangle with rounded corners as shown in FIG. 39 (c). Of course, the formed electrode can also be applied as the resonator electrode 4.

  Moreover, although the example which applied the dielectric substrate 2 as a board | substrate was shown in the said Example, semiconductor substrates, such as a gallium arsenide dielectric substrate and a silicon dielectric substrate, can also be applied as a board | substrate.

  Further, in the fifth embodiment, the example in which the strip line 3 and the resonator electrode 4 are connected by the wire 7 has been shown, but a configuration in which the connection is made by an air bridge can also be adopted.

  Moreover, in the said Example, the length from the open end 41 of each resonator electrode 4 (4A, 4B) to the short circuit end 42 is made into the wavelength in the center frequency in the zone | band of each resonator electrode 4 (4A, 4B). Although the length is set to a quarter length, the “quarter length of the wavelength” at the center frequency does not have to be strictly a quarter. If the length is “1”, it is good. In addition, the interval D between the adjacent resonator electrodes 4 (4A) or between the resonator electrodes 4 (4B) is set to λg / 4. However, this “λg / 4” is also strictly a quarter of the wavelength. It does not have to be set, and may be set to “about λg / 4”.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a filter according to a first embodiment of the present invention with a part broken away. It is a top view of a filter. It is arrow AA sectional drawing of FIG. It is the elements on larger scale for demonstrating the dimension and direction of each resonator electrode, and the space | interval of resonator electrodes. It is a top view for demonstrating the effect | action and effect of a filter. It is a schematic sectional drawing for demonstrating the electric field coupling of each resonator electrode and stripline. It is a diagram which shows the coupling coefficient of adjacent resonator electrodes. It is a diagram which shows the zone | band characteristic obtained by actual measurement. It is a diagram which shows the zone | band characteristic obtained by simulation. It is a top view which shows an example of the filter which concerns on 2nd Example of this invention. It is a top view which shows the other example of the filter which concerns on 2nd Example. It is a top view which shows an example of the filter which concerns on 3rd Example of this invention. It is a top view which shows the other example of the filter which concerns on 3rd Example. It is sectional drawing which shows the filter which concerns on 4th Example of this invention. It is a top view which shows the filter which concerns on 5th Example of this invention. It is arrow BB sectional drawing of FIG. It is a diagram which shows the zone | band characteristic obtained by simulation. It is a top view of the filter which has five pairs of resonator electrodes to which wires are connected. It is a diagram which shows the simulation result of the filter of FIG. It is a top view of the filter which has a pair of resonator electrode to which a wire is connected. It is a diagram which shows the simulation result of the filter of FIG. It is a top view of the filter in which the wire is connected only to the resonator electrode on one side of the stripline. It is a diagram which shows the simulation result of the filter of FIG. FIG. 6 is a plan view of a filter in which wires are alternately connected to resonator electrodes on both sides of a strip line. It is a diagram which shows the simulation result of the filter of FIG. It is a top view of the filter with which two wires were connected to each resonator electrode. It is a diagram which shows the simulation result of the filter of FIG. It is a top view of the filter with which the wire was connected to the short circuit end of each resonator electrode. It is a diagram which shows the simulation result of the filter of FIG. It is a top view of the filter concerning the 1st modification of the 5th example. It is CC sectional view taken on the line of FIG. It is a top view of the filter concerning the 2nd modification of the 5th example. It is arrow DD sectional drawing of FIG. It is a top view of the filter concerning the 3rd modification of the 5th example. It is a top view of the filter concerning the 4th modification of the 5th example. It is a top view of the filter concerning the 5th modification of the 5th example. It is arrow EE sectional drawing of FIG. It is a block diagram which shows the high frequency module which concerns on 6th Example of this invention. It is a top view which shows the various modifications of a resonator electrode.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Filter, 2 ... Dielectric substrate, 2a ... Front surface, 2b ... Back surface, 3 ... Strip line, 4, 4A, 4B ... Resonator electrode, 5 ... Ground electrode, 6 ... Via hole, 7 ... Wire, 8 ... High frequency module 30 ... side edge, 30 ', 40' ... protrusion, 31 ... input end, 32 ... output end, 33 ... part, 40 ... pad portion, 40a ... end side, 41 ... open end, 42 ... short-circuit end, 43 ... Central part 71 ... One end E ... Electric field S ... In-band signal S '... Out-of-band signal S11, S11' ... Reflection coefficient curve, S21, S21 '... Transmission coefficient curve

Claims (11)

A substrate, a signal input / output strip line provided on the surface of the substrate, each set to a length of about a quarter of the wavelength at the center frequency in the band, and one end is an open end And a plurality of resonator electrodes arranged at intervals of about one quarter of the wavelength on both sides of the stripline with the other end being a short-circuited end,
With the open end of each resonator electrode close to the strip line, the length direction of the resonator electrode from the open end to the short-circuit end is perpendicular to the length direction of the strip line. Set to
The open ends of the resonator electrode on one side and the resonator electrode on the other side of the strip line are opposed to each other.
A filter characterized by that. The filter of claim 1,
By adjusting the characteristic impedance of the part by widening or narrowing the width of the part of the stripline, where the open ends of the resonator electrodes face each other,
A filter characterized by that. The filter of claim 1,
The capacitance between the resonator electrode and the strip line was adjusted by changing the opposing length of the edge of the open end of each resonator electrode and the side of the strip line facing the end.
A filter characterized by that. The filter according to claim 1 or 2,
The plurality of resonator electrodes are formed inside the substrate.
A filter characterized by that. A substrate, a signal input / output strip line provided on the surface of the substrate, each set to a length of about one quarter of the wavelength at the center frequency in the band, and at least one end is a short-circuited end And a plurality of resonator electrodes arranged at intervals of about one quarter of the wavelength on one side or both sides of the stripline,
The length direction of the resonator electrode is set perpendicular to the length direction of the strip line,
A wire or air bridge is connected directly between the stripline and any or all of the plurality of resonator electrodes;
A filter characterized by that. The filter according to claim 5, wherein
The plurality of resonator electrodes are arranged on both sides of the strip line,
The wire or air bridge is connected directly between all of the plurality of resonator electrodes located on one side of the stripline and the stripline.
A filter characterized by that. The filter according to any one of claims 1 to 6,
The strip line constitutes a microstrip line together with a ground electrode provided on the back surface or inside of the substrate.
A filter characterized by that. The filter according to any one of claims 1 to 7,
The substrate is a dielectric substrate.
A filter characterized by that. The filter according to any one of claims 1 to 7,
The substrate is a semiconductor substrate.
A filter characterized by that. The filter according to claim 9, wherein
The semiconductor substrate is a gallium arsenide substrate or a silicon substrate.
A filter characterized by that. The filter according to any one of claims 1 to 10, comprising:
A high-frequency module characterized by that.

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