JP2013093811A - Resonator, filter, and filter bank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resonator which, even when subjected to mechanical vibration, can restrain the breakage or the temporal change in characteristics of a signal conductor.SOLUTION: The resonator includes, in addition to ground conductors 11, 12 and 13 laid on the same plane, a signal conductor 14 which is connected at one end to the ground conductor 11 and open at the other end, whose length is an odd multiple of about 1/4 wavelength of a resonance frequency, and a dielectric body 15 which is connected at one end to the ground conductor 13 and connected at the other end to the signal conductor 14. Owing to this composition, the resonator can restrain the breakage or the temporal change in characteristics of the signal conductor even when it is subjected to mechanical vibration.

Description

  The present invention relates to a resonator used in, for example, a microwave band, and a filter and a filter bank using the resonator.

A conventional distributed constant bandpass filter achieves desired electrical characteristics by arranging a plurality of open-ended stubs between input and output terminals.
The open end stub is a signal conductor having one end connected to a ground conductor and the other end being open, and having a length that is an odd multiple of about ¼ wavelength in the passband. (For example, refer nonpatent literature 1).

G. Matthaei, “Microwave Filters, Impedance-Matching Networks, and Coupling Structures” (pp. 614, Artech House, 1980).

  Since the conventional pass filter is configured as described above, if it is realized using a hollow triplate line or a hollow coplanar line without using a dielectric substrate for the purpose of reducing loss, The vicinity of the tip of the open stub (the signal conductor whose length is an odd multiple of about ¼ wavelength) is not mechanically supported. For this reason, when a band-pass filter is formed using a thin metal plate, when a vibration is applied from the outside, the signal conductor, which is an open-ended stub, mechanically resonates. There existed a subject that the part which connects a conductor may fracture | rupture by metal fatigue.

In addition, when a bandpass filter is formed using a thin metal plate, the signal conductor mechanically vibrates when vibration is applied from the outside, so the resonance frequency of the resonator constituting the filter changes with time. Thus, there is a problem that the characteristics of the filter change with time.
In addition, when the temperature around the resonator and the filter changes, the signal conductor and ground conductor constituting the resonator expand or contract and the size of the resonator changes, so the resonance frequency of the resonator changes. There is a problem that the pass frequency of the filter changes.

The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a resonator capable of suppressing signal conductor breakage and temporal characteristic change even when mechanical vibration is applied. To do.
Another object of the present invention is to obtain a resonator that can suppress fluctuations in resonance frequency due to changes in ambient temperature.
Another object of the present invention is to obtain a filter and a filter bank using the above-described resonator.

  The resonator according to the present invention includes a first ground conductor, a second ground conductor provided on the same plane as the first ground conductor, one end connected to the first ground conductor, and the other end Is connected to the second ground conductor, one end is connected to the first ground conductor, the other end is open, and the length is about ¼ wavelength of the resonance frequency. A signal conductor that is an odd multiple, one end connected to at least one of the first ground conductor, the second ground conductor, and the third ground conductor, and the other end connected to the signal conductor. It is comprised from a dielectric material.

  According to this invention, the first ground conductor, the second ground conductor provided on the same plane as the first ground conductor, one end is connected to the first ground conductor, and the other end is the first ground conductor. A third ground conductor connected to the second ground conductor, one end connected to the first ground conductor, the other end open, and a length that is an odd multiple of about ¼ wavelength of the resonance frequency. And a dielectric having one end connected to at least one of the first ground conductor, the second ground conductor, and the third ground conductor and the other end connected to the signal conductor. Therefore, even if mechanical vibration is applied, there is an effect that it is possible to suppress the breakage of the signal conductor and the temporal characteristic change.

1 is an overhead view showing a resonator according to a first embodiment of the present invention. It is a block diagram (top view of the metal plate 1) which shows the resonator by Embodiment 1 of this invention. FIG. 3 is a cross-sectional view of A-A ′ in the resonator of FIG. 2. It is a block diagram (top view of the metal plate 1) which shows the other resonator by Embodiment 1 of this invention. It is an overhead view which shows the other resonator by Embodiment 1 of this invention. It is a block diagram (top view of the metal plate 1) which shows the resonator by Embodiment 2 of this invention. FIG. 7 is a cross-sectional view of B-B ′ in the resonator of FIG. 6. It is a block diagram (top view of the metal plate 1) which shows the other resonator by Embodiment 2 of this invention. FIG. 7 is a cross-sectional view of B-B ′ in the resonator of FIG. 6. It is a block diagram which shows the filter bank by Embodiment 3 of this invention. It is a top view which shows filter 21A, 21B, 21C of the filter bank by Embodiment 3 of this invention. It is sectional drawing of D-D 'in the filter of FIG. It is sectional drawing of D-D 'in case the metal housing | casing 7 is arrange | positioned above the main surface of signal conductor 14a, 14b.

Embodiment 1 FIG.
Hereinafter, preferred embodiments of a resonator using a hollow coplanar line will be described with reference to the drawings.
FIG. 1 is a bird's-eye view showing a resonator according to the first embodiment of the present invention, and FIG. 2 is a configuration diagram (a top view of the metal plate 1) showing the resonator according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view taken along the line AA ′ in the resonator of FIG.

1 to 3, a metal plate 1 is a single metal plate forming each element of the resonator (ground conductors 11 to 13, signal conductor 14, etc.).
The metal housing 2 is a fourth ground conductor disposed below the main surface of the signal conductor 14, and the metal housing 2 is electrically connected to the ground conductors 11 and 12.
Screws 3 to 6 are members for fixing the metal plate 1 to the metal casing 2.

The ground conductor 11 is a first ground conductor, and an input / output line 16 (first input / output conductor) and an input / output line 17 (second input / output conductor) are connected to the ground conductor 11.
The ground conductor 12 is a second ground conductor provided on the same plane as the ground conductor 11.
The ground conductor 13 is a third ground conductor having one end connected to the ground conductor 11 and the other end connected to the ground conductor 12.
The signal conductor 14 is an open-ended stub having one end connected to the ground conductor 11 and the other end open, and the length of the signal conductor 14 is an odd multiple of about ¼ wavelength of the resonance frequency.

The dielectric 15 has one end connected to the ground conductor 13 and the other end connected to the signal conductor 14 for the purpose of fixing the signal conductor 14 to the ground conductor.
In the first embodiment, a dielectric having a negative dielectric constant temperature characteristic is used as the dielectric 15.
1 to 3, the one end of the dielectric 15 is connected to the ground conductor 13, but it is sufficient that the signal conductor 14 can be fixed to the ground conductor. The ground conductor 11 or the ground conductor 12 may be connected.
That is, one end of the dielectric 15 only needs to be connected to at least one of the ground conductors 11, 12, and 13.

Next, the operation will be described.
The signal conductor 14 is an open-ended stub having one end connected to the ground conductor 11 and the other end open, and the length of the signal conductor 14 is an odd multiple of about ¼ wavelength of the resonance frequency.
For this reason, the resonator of FIG. 1 electrically resonates at a frequency that is an odd multiple of about ¼ wavelength of the resonance frequency.

Therefore, for example, when a signal is input from the input / output line 16, only a component in the vicinity of the frequency at which the signal conductor 14 electrically resonates is coupled to the resonator.
Further, only the component near the frequency at which the signal conductor 14 electrically resonates is coupled to the input / output line 17 and output.
That is, the resonator of FIG. 1 operates as a single-stage bandpass filter.

In the first embodiment, the signal conductor 14 is fixed to the ground conductor 13 by the dielectric 15.
For this reason, even if mechanical vibration is applied to the resonator of FIG. 1 from the outside, the vibration of the signal conductor 14 does not increase and mechanical resonance hardly occurs, and the signal conductor 14 can be prevented from being broken. it can.
Further, since the vibration of the signal conductor 14 does not increase, the temporal change in the resonance frequency of the resonator can be reduced.

In the first embodiment, the signal conductor 14 is a dielectric having a negative dielectric constant temperature characteristic, such as polyimide.
For example, when the temperature of the resonator increases, the signal conductor 14 expands to increase the electrical length and the resonance frequency decreases, but when the dielectric 15 having a negative dielectric constant temperature characteristic is used, The dielectric constant of 15 decreases and the resonance frequency increases.
For this reason, even if the signal conductor 14 expands or contracts due to the temperature change of the resonator and the resonance frequency changes, the change in the resonance frequency and the change in the resonance frequency due to the dielectric 15 cancel each other. A resonator having a small variation in the resonance frequency due to a temperature change can be obtained.

  As apparent from the above, according to the first embodiment, in addition to the ground conductors 11, 12, 13 provided on the same plane, one end is connected to the ground conductor 11 and the other end is opened. A signal conductor 14 whose length is an odd multiple of about ¼ wavelength of the resonance frequency, and a dielectric 15 having one end connected to the ground conductor 13 and the other end connected to the signal conductor 14. Therefore, even if mechanical vibration is applied, there is an effect that it is possible to suppress breakage of the signal conductor 14 and temporal characteristic change.

  Further, according to the first embodiment, since the dielectric 15 having a negative dielectric constant temperature characteristic is used as the dielectric 15 connected to the signal conductor 14, the resonance frequency fluctuates due to ambient temperature changes. The effect which can suppress is produced.

In the first embodiment, the signal conductor 14 is a straight conductor. However, the signal conductor 14 is not limited to a straight conductor. For example, as shown in FIG. The part may be bent in a direction along the ground conductors 11 and 12.
Since a part of the signal conductor 14 is bent in a direction along the ground conductors 11 and 12, the resonance frequency does not change, and the distance between the ground conductor 11 and the ground conductor 12 can be shortened. Can be reduced in size. That is, the filter width can be narrowed without changing the passband.

In the first embodiment, the metal casing 2 is disposed below the main surface of the signal conductor 14. However, as shown in FIG. 5, the metal housing 2 is also disposed above the main surface of the signal conductor 14. Alternatively, a metal housing 7 that is a fourth ground conductor may be disposed, and the metal housing 7 may be electrically connected to the ground conductors 11 and 12.
As shown in FIG. 5, the two metal casings 2 and 7 cover the metal plate 1, so that the leakage of the electromagnetic field to the periphery of the resonator can be reduced, and the amount of interference with the peripheral circuit is reduced. There is an effect that can be.

Embodiment 2. FIG.
6 is a configuration diagram (a top view of the metal plate 1) showing a resonator according to a second embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along the line BB ′ in the resonator of FIG.
6 and 7, the same reference numerals as those in FIGS. 2 and 3 indicate the same or corresponding parts, and thus the description thereof is omitted.
The signal conductor 14a is a tip open stub having one end connected to the ground conductor 11 and the other end open, and the length of the signal conductor 14a is an odd multiple of about ¼ wavelength of the resonance frequency.
The signal conductor 14b is an open-ended stub having one end connected to the ground conductor 11 and the other end open, and the length of the signal conductor 14b is an odd multiple of about ¼ wavelength of the resonance frequency.

The dielectric 15a has one end connected to the ground conductor 13 and the other end connected to the signal conductor 14a for the purpose of fixing the signal conductor 14a to the ground conductor.
The dielectric 15b has one end connected to the ground conductor 13 and the other end connected to the signal conductor 14b for the purpose of fixing the signal conductor 14b to the ground conductor.
In the second embodiment, dielectrics having a negative dielectric constant temperature characteristic are used as the dielectrics 15a and 15b.
6 and 7 show the dielectrics 15a and 15b having one end connected to the ground conductor 13, the signal conductors 14a and 14b only need to be fixed to the ground conductor. One end of 15 a and 15 b may be connected to the ground conductor 11 or the ground conductor 12.
That is, one end of the dielectrics 15a and 15b may be connected to at least one of the ground conductors 11, 12, and 13.

Next, the operation will be described.
The signal conductors 14a and 14b are open-ended stubs having one end connected to the ground conductor 11 and the other end open, and the length of the signal conductors 14a and 14b is an odd multiple of about ¼ wavelength of the resonance frequency. It is.
For this reason, the resonator of FIG. 6 electrically resonates at a frequency that is an odd multiple of about ¼ wavelength of the resonance frequency.

Therefore, for example, when a signal is input from the input / output line 16, only a component near the frequency at which the signal conductor 14a electrically resonates is coupled to the resonator in the input signal.
Further, only the component near the frequency at which the signal conductor 14b electrically resonates is coupled to the adjacent resonator.
Further, only the component near the frequency at which the signal conductor 14b electrically resonates is coupled to the input / output line 17 and output.
That is, the resonator of FIG. 6 operates as a two-stage bandpass filter.

In the second embodiment, two resonators composed of the ground conductors 11, 12, and 13 are used. However, three or more resonators composed of the ground conductors 11, 12, and 13 are used. You may do it.
By using three or more resonators composed of the ground conductors 11, 12, and 13, sharper passage characteristics (frequency characteristics) than when two resonators composed of the ground conductors 11, 12, and 13 are used. Can be realized.

In the second embodiment, the signal conductors 14a and 14b are linear conductors. However, the signal conductors 14a and 14b are not limited to linear conductors. For example, as shown in FIG. , 14b may be bent in a direction along the ground conductors 11 and 12.
Since part of the signal conductors 14a and 14b is bent in the direction along the ground conductors 11 and 12, the resonance frequency does not change, and the distance between the ground conductor 11 and the ground conductor 12 can be shortened. It becomes possible to reduce the size of the resonator. That is, the filter width can be narrowed without changing the passband.

In the second embodiment, the metal housing 2 is disposed below the main surfaces of the signal conductors 14a and 14b. However, as shown in FIG. 9, the main surfaces of the signal conductors 14a and 14b. A metal housing 7 may be disposed above the metal housing 7 so that the metal housing 7 is electrically connected to the ground conductors 11 and 12.
As shown in FIG. 9, by covering the metal plate 1 with the two metal casings 2 and 7, the leakage of the electromagnetic field to the periphery of the resonator can be reduced, and the amount of interference with the peripheral circuit is reduced. There is an effect that can be.

Embodiment 3 FIG.
10 is a block diagram showing a filter bank according to Embodiment 3 of the present invention.
In FIG. 10, filters 21A, 21B, and 21C are the resonators of the second embodiment that operate as, for example, a two-stage bandpass filter.
However, in the filters 21A, 21B, and 21C, the lengths of the internal signal conductors 14a and 14b are different from each other, and the passbands are different.
Here, an example in which the filters 21A, 21B, and 21C are two-stage bandpass filters is shown, but the resonator according to the first embodiment that operates as a one-stage bandpass filter may be used.

The switch 24 is a switching member that connects any one of the filters 21A, 21B, and 21C to the input / output terminal 22.
The switch 25 is a switching member that connects any one of the filters 21A, 21B, and 21C to the input / output terminal 23.

FIG. 11 is a top view showing filters 21A, 21B, and 21C of the filter bank according to Embodiment 3 of the present invention.
FIG. 12 is a cross-sectional view taken along the line DD ′ in the filter of FIG.
FIG. 11 shows the resonators of the second embodiment that operate as a two-stage bandpass filter, in which the lengths of the signal conductors 14a and 14b of the resonators are changed to each other, and the ground conductors of the adjacent resonators. 11 and the ground conductor 12 are arranged to be connected.

Next, the operation will be described.
Here, for convenience of explanation, the pass band of the signal by the filter 21A is f _{A to} f _B , the pass band of the signal by the filter 21B is f _{B to} f _C , and the pass band of the signal by the filter 21C is f _{C to} f _D. And
For example, when it is necessary to pass only a component having a frequency in the range of f _{A to} f _B among signals input from the input / output terminal 22, a control circuit (not shown) operates the switches 24 and 25, The filter 21A is connected to the input / output terminals 22 and 23.
As a result, of the signal input from the input / output terminal 22, only the component having a frequency in the range of f _{A to} f _B passes through the filter 21 A and is output to the input / output terminal 23.

For example, when it is necessary to pass only a component having a frequency in the range of f _{B to} f _C among signals input from the input / output terminal 22, a control circuit (not shown) operates the switches 24 and 25, The filter 21B is connected to the input / output terminals 22 and 23.
As a result, of the signal input from the input / output terminal 22, only the component whose frequency is in the range of f _{B to} f _C passes through the filter 21 </ _b > _B and is output to the input / output terminal 23.

For example, when it is necessary to pass only a component having a frequency in the range of f _{C to} f _D among the signals input from the input / output terminal 22, a control circuit (not shown) operates the switches 24 and 25, The filter 21C is connected to the input / output terminals 22 and 23.
As a result, of the signal input from the input / output terminal 22, only the component whose frequency is in the range of f _{C to} f _D passes through the filter 21 </ b> _C and is output to the input / output terminal 23.

  As apparent from the above, according to the third embodiment, the switches 24, 21B, 21C for selecting an arbitrary filter 21 from the filters 21A, 21B, 21C having different lengths of the signal conductors 14a, 14b. 25 is provided, so that only the signal of a specific frequency band among the signals input from the input / output terminal 22 can be passed.

  Further, according to the third embodiment, since a plurality of filters are integrated and configured (see FIG. 11), each ground conductor of each filter is connected without breaks. By etching or punching the metal plate 1, a plurality of filters can be manufactured at a time, and it is possible to realize a filter bank that can be manufactured easily and at a low cost.

In the third embodiment, the metal casing 2 is disposed below the main surfaces of the signal conductors 14a and 14b. However, as shown in FIG. 13, above the main surfaces of the signal conductors 14a and 14b. Alternatively, a metal casing 7 may be disposed so that the metal casing 7 is electrically connected to the ground conductors 11 and 12.
As shown in FIG. 13, by covering the metal plate 1 with the two metal casings 2 and 7, it is possible to reduce the leakage of the electromagnetic field to the periphery of adjacent filters and filter banks. There is an effect that the amount of interference between the peripheral circuit and the peripheral circuit can be reduced.

In the third embodiment, the filter bank is configured by using three filters having different pass bands. However, the present invention is not limited to this. For example, two filters having different pass bands, or The filter bank may be configured using four or more filters having different pass bands.
By using two filters having different pass bands, it is possible to reduce the size of the filter bank. Further, by using four or more filters having different pass bands, it is possible to separate signals having different frequency bands.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  DESCRIPTION OF SYMBOLS 1 Metal plate, 2,7 Metal housing (4th ground conductor), 3-6 screw, 11 Ground conductor (1st ground conductor), 12 Ground conductor (2nd ground conductor), 13 Ground conductor (1st 3 ground conductor), 14, 14a, 14b signal conductor, 15, 15a, 15b dielectric, 16 input / output line (first input / output conductor), 17 input / output line (second input / output conductor), 21A, 21B, 21C filter, 22, 23 I / O terminal, 24, 25 switch.

Claims (8)

A first ground conductor;
A second ground conductor provided on the same plane as the first ground conductor;
A third ground conductor having one end connected to the first ground conductor and the other end connected to the second ground conductor;
A signal conductor having one end connected to the first ground conductor and the other end open, the length being an odd multiple of about a quarter wavelength of the resonance frequency;
A dielectric having one end connected to at least one of the first ground conductor, the second ground conductor, and the third ground conductor and the other end connected to the signal conductor; Resonator provided.   2. The resonator according to claim 1, wherein a part of the signal conductor is bent in a direction along the first and second ground conductors.   The resonator according to claim 1 or 2, wherein the first ground conductor, the second ground conductor, the third ground conductor, and the signal conductor are formed of a single metal plate. A fourth ground conductor is disposed above or below the main surface of the signal conductor,
4. The resonator according to claim 1, wherein the fourth ground conductor is electrically connected to the first and second ground conductors. 5.   5. The resonator according to claim 1, wherein a dielectric having a negative dielectric constant temperature characteristic is used as the dielectric connected to the signal conductor.   A filter in which the resonator according to any one of claims 1 to 5 is disposed between a first input / output conductor and a second input / output conductor.   A filter bank in which a plurality of filters according to claim 6 are arranged in the same plane.   8. The filter bank according to claim 7, further comprising a switch for selecting an arbitrary filter from a plurality of filters having different lengths of signal conductors constituting the resonator.

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