JP2010283459A - Band-stop filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a band-stop filter, having sufficient electric power resistance applicable to a filter for a transmitter used for a radio base station of a portable telephone. <P>SOLUTION: The band-stop filter has a dual-mode resonator including a disk type resonance pattern. A first transmission line passes farther than the outside of the outer circumferential line of the resonance pattern and is electrically connected to the resonance pattern. A second transmission line is electrically connected to the resonance pattern at a first end part. A resonance signal excited by a signal transmitted in the first transmission line to the dual mode resonator is extracted to the second transmission line. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a band elimination filter using a disk type dual mode resonator.

  In recent years, with the spread and development of mobile phones, high-speed and large-capacity transmission technology has become indispensable. In order to realize high-speed and large-capacity communication, it is necessary to secure a wide frequency band, and the frequency band used for wireless communication is shifted toward higher frequencies. In such a high-frequency band, a filter characteristic for selectively passing only a desired frequency component and steeply blocking other frequency components is required for a filter for wireless communication. Further, miniaturization and weight reduction are strongly demanded for radio communication equipment using high-frequency circuit elements.

  A filter using a disk resonator is known as a filter used in a high frequency band. The disk-type resonator includes a circular conductive pattern having a radius of an electric path length of a half wavelength or an integral multiple of the half wavelength. In order to increase space efficiency, a method has been proposed in which two resonance modes (dual mode) are generated by one resonator to obtain a steeper filter characteristic.

  Further, a band elimination filter in which an arc-shaped resonance pattern is arranged on the side of the transmission line has been proposed.

JP 2008-295024 A JP-A-10-308611

Futatsumori, S, et al., "Microwave superconducting reaction-type transmitting filter using split open-ring resonator", IEEE Electronics Letters, Vol.42, No.7 (2006)

  Due to the non-linear characteristics of the power amplifier for transmission, the amplified signal includes unnecessary frequency components. The power of unnecessary frequency components (noise) is smaller than the signal power. When transmitting a frequency component of a signal using a band-pass filter and removing an unnecessary frequency component, a high-power signal passes through the filter. For this reason, the power durability of the resonator used for the filter must be increased.

  When removing unnecessary frequency components using a band-reject filter, only the unnecessary frequency components are excited in the resonator, so the power durability of the resonator is increased compared to using a band-pass filter. It does not have to be. However, it cannot be said that the conventional band elimination filter has sufficient power durability as a filter for a transmitter used in a radio base station of a mobile phone.

According to one aspect of the invention,
A dual mode resonator including a disk-shaped resonance pattern;
A first transmission line that passes outside the outer periphery of the resonance pattern and is electrically coupled to the resonance pattern;
And a second transmission line electrically coupled to the resonance pattern at a first end, and a resonance signal excited in the dual mode resonator by a signal transmitted through the first transmission line. , A band elimination filter taken out to the second transmission line is provided.

  Since the power of the resonance signal generated in the dual mode resonator is drawn to the second transmission line, it is possible to suppress the power of the resonance signal from staying in the resonance pattern. Thereby, power durability can be improved.

(1A) is a sectional view of the band elimination filter according to the first embodiment, and (1B) is a plane sectional view of the band elimination filter according to the first embodiment. 6 is a graph showing simulation results of transmission characteristics and reflection characteristics of the band elimination filter according to Example 1. 6 is a plan view of a conductive pattern of a band elimination filter according to Embodiment 2. FIG. (4A) is a block diagram of a transmitter to which the band elimination filter according to the second embodiment is applied, (4B) is a graph showing the transmission characteristics of the band elimination filter according to the second embodiment, and (4C) is the power (4D) is a graph showing the spectrum of the high-frequency signal amplified by the power amplifier, and (4E) is a graph showing the spectrum of the high-frequency signal that has passed through the band elimination filter. It is a graph which shows a spectrum. (5A) is a plan view showing a conductive pattern of a band elimination filter according to Example 3, and (5B) is a plan view showing a conductive pattern of a band elimination filter according to Modification 1 of Example 3. FIG. (6A) is a plan view showing the conductive pattern of the band elimination filter according to the second modification of the third embodiment, and (6B) is a plan view showing the conductive pattern of the band elimination filter according to the third modification of the third embodiment. is there. (7A) is a sectional view of the band elimination filter according to the fourth embodiment, and (7B) is a plane sectional view of the band elimination filter according to the fourth embodiment. 7 is a cross-sectional view of a dielectric substrate and a conductive pattern of a band elimination filter according to Example 5. FIG.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1A shows a cross-sectional view of the band elimination filter according to the first embodiment, and FIG. 1B shows a flat cross-sectional view taken along one-dot chain line 1B-1B in FIG. A cross-sectional view taken along one-dot chain line 1A-1A in FIG. 1B corresponds to FIG. 1A.

  As shown in FIG. 1A, the resonance pattern 21 and the first transmission line 22 are formed on the main surface of the dielectric substrate 20, and the ground film 27 is formed on the back surface. The dielectric substrate 20 is disposed on the bottom surface of the main body 15A of the package 15. The ground film 27 contacts the bottom surface of the package body 15A.

  The package body 15A is a rectangular parallelepiped container having an upper opening, and the opening is closed with a top plate 15B. The package body 15A and the top plate 15B constitute a package 15 that defines a closed space inside. The package 15 is made of, for example, oxygen-free copper having excellent thermal conductivity and conductivity. In addition to oxygen-free copper, pure aluminum, an aluminum alloy, a copper alloy, or the like may be used. Further, Kovar, Invar, 42 alloy or the like having a thermal contraction rate close to that of the dielectric substrate 20 may be used for the package 15. The package 15 is plated with gold having a thickness of about 2 μm in order to prevent deterioration of electrical characteristics due to surface oxidation.

The dielectric substrate 20 is made of magnesium oxide (MgO) having a (100) crystal plane appearing on the main surface, and its thickness is 0.5 mm. As a material of the dielectric substrate 20, a dielectric material having a high dielectric constant and low loss such as LaAlO ₃ and sapphire may be used.

  An input connector 35 and an output connector 36 are attached to the side wall of the package body 15A. The center conductor of the input connector 35 is connected to the input end 22A of the first transmission line 22 by, for example, an Au wire having a diameter of 25 μm. The center conductor of the output connector 36 is connected to the output end 22B of the first transmission line 22 by, for example, an Au wire having a diameter of 25 μm. In place of the Au wire, an Au ribbon or an Al wire may be used.

  As shown in FIG. 1B, a resonance pattern 21, a first transmission line 22, a second transmission line 23, and a third transmission line 24 are formed on the main surface of the dielectric substrate 20. The resonance pattern 21, the first to third transmission lines 22 to 24, and the ground film 27 (FIG. 1A) have a microstrip line structure.

As an example, when a 5 GHz band-pass filter is fabricated on the dielectric substrate 20, the resonance pattern 21 has a circular planar shape with a diameter of 11 mm. At this time, the relationship between the wavelength λr of the high frequency signal resonating in the resonance pattern 21 and the diameter d of the resonance pattern is
d = (n / 2) λr (n is a natural number) (1)
It becomes. Here, a frequency corresponding to the wavelength λr when n = 1 is referred to as a “basic resonance frequency”. That is, the signal of the basic resonance frequency of the resonance pattern 21 has a wavelength twice that diameter, that is, 22 mm. The actual resonance wavelength can be determined from the effective dielectric constant of the microstrip line and the electrically measured resonance frequency. Actually, the wavelength of the resonating high-frequency signal is slightly deviated from the resonance wavelength λr obtained by the above equation (1) due to leakage of electromagnetic waves from the edge of the resonance pattern 21 or the like.

  First to fourth coupling positions C <b> 1 to C <b> 4 are defined on the outer peripheral line of the resonance pattern 21. The first coupling position C1 and the second coupling position C2 are set such that the radius having the first coupling position C1 as an end point and the radius having the second coupling position C2 as an end point are orthogonal to each other. Has been. The third coupling position C3 and the fourth coupling position C4 are defined as point-symmetrical positions of the first coupling position C1 and the second coupling position C2 with respect to the center of the resonance pattern 21, respectively.

  The first transmission line 22 passes outside the outer peripheral line of the resonance pattern 21 and is electrically coupled (capacitively coupled) to the resonance pattern 21 at the first coupling position C1 and in the vicinity thereof. One input end 23A of the second transmission line 23 and its vicinity are electrically coupled (capacitively coupled) to the resonance pattern 21 at the second coupling position C2 and its vicinity.

  The first transmission line 22 includes a linear portion on the input end 22A side, a linear portion on the output end 22B side, and a coupling portion that couples both. The second transmission line 23 includes a coupling portion on the input end 23A side and a linear portion on the output end 23B side connected thereto. Each coupling portion of the first transmission line 22 and the second transmission line 23 is curved so as to be parallel to the circumferential outer peripheral line of the resonance pattern 21. The distance between each of the coupling portions of the first and second transmission lines 22 and 23 and the resonance pattern 21 is, for example, 25 to 100 μm. The degree of coupling between each of the first and second transmission lines 22 and 23 and the resonance pattern 21 can be increased by curving the coupling portion.

  One end of the third transmission line 24 is capacitively coupled to the resonance pattern 21 at and near the third coupling position C3, and the other end is capacitively coupled to the resonance pattern 21 at and near the fourth coupling position C4. Accordingly, the third transmission line 24 capacitively couples the third coupling position C3 and the fourth coupling position C4 of the resonance pattern 21 to each other. The planar shape of both ends of the third transmission line 24 is a crescent shape having a curvature along the outer periphery of the resonance pattern 21. The space | interval of the crescent-shaped part of the 3rd transmission line 24 and the resonance pattern 21 is 25-100 micrometers, for example. By making the end of the third transmission line 24 into a crescent shape, the degree of coupling between the third transmission line 24 and the resonance pattern 21 can be increased. The third transmission line 24 causes dual mode resonance in the resonance pattern 21. Thus, the resonance pattern 21 and the third transmission line 24 operate as a dual mode resonator.

The resonance pattern 21, the first to third transmission lines 22 to 24, and the ground film 27 (FIG. 1A) are formed of YBa ₂ Cu ₃ O _{6 + x} (hereinafter referred to as “YBCO”), and the thickness thereof. Is 100-500 nm. In addition to YBCO, these conductive patterns may be formed of an oxide superconducting material that exhibits a superconducting state at a liquid nitrogen temperature. Examples of oxide superconducting materials include R-Ba-Cu-O-based (R is Nb, Ym, Sm, or Ho) material, Bi-Sr-Ca-Cu-O-based material, Pb-Bi-Sr-Ca. -cu-O-based _{material, CuBa p Ca q Cu r O} x based material (1.5 <p <2.5,2.5 <q <3.5,3.5 <r <4.5) or the like Can be mentioned. The widths of the first to third transmission lines 22 to 24 are 0.5 mm when formed on the dielectric substrate 20, and the characteristic impedance of the waveguide at this time is 50Ω.

  A connection electrode in which a Cr film, a Pd film, and an Au film are laminated in this order on the surfaces of the input end 22A and the output end 22B of the first transmission line 22 and the output end 23B of the second transmission line 23. Is formed.

  The YBCO film can be formed by, for example, a pulse laser deposition method. Each YBCO pattern on the main surface of dielectric substrate 20 can be formed using a normal photolithography technique. The connection electrode in which the Cr film, the Pd film, and the Au film are laminated can be formed by using a vapor deposition and lift-off method.

  An input connector 35 and output connectors 36 and 37 are attached to the side wall of the package body 15A. The center conductors of the input connector 35 and the output connector 36 are connected to connection electrodes formed at the input end 22A and the output end 22B of the first transmission line 22, respectively. The center conductor of the output connector 37 is connected to the connection electrode formed at the output end 23 </ b> B of the second transmission line 23.

  The center conductor of the output connector 37 is connected to the load impedance 38 outside the package 15. The load impedance 38 is equal to the characteristic impedance of the second transmission line 23.

  A high-frequency signal input from the input connector 35 is transmitted from the input end 22A to the output end 22B through the first transmission line 22. A resonance signal is excited in the resonance pattern 21 by a high-frequency signal transmitted through the first transmission line 22. The third transmission line 24 causes dual mode resonance. Since the resonance pattern 21 and the second transmission line 23 are coupled at the second coupling position C <b> 2, the power of the resonance signal is extracted to the second transmission line 23.

  The high frequency signal taken out to the second transmission line 23 is transmitted to the output end 23 </ b> B, and the power of the high frequency signal is consumed by the load impedance 38. Since the load impedance 38 is equal to the characteristic impedance of the second transmission line 23, no reflection occurs at the output end 23 </ b> B of the second transmission line 23.

FIG. 2 shows a simulation result of the frequency characteristics of the band elimination filter according to the first embodiment. The horizontal axis represents frequency in the unit “GHz”, and the vertical axis represents S parameter in the unit “dB”. The reflection parameter S ₁₁ , the transmission parameter S ₂₁ , and the removal parameter S ₃₁ are respectively the magnitude of the reflected wave returning to the input end 22A and the output end 22B when a high frequency signal is input from the input end 22A of the first transmission line 22. The magnitude | size of the transmitted wave output and the magnitude | size of the high frequency signal output to the output end 23B of the 2nd transmission line 23 are shown.

In the frequency 5GHz vicinity, transmission parameters S ₂₁ has been lowered, it can be seen that the bandwidth of the high frequency signal 5GHz vicinity is eliminated. In-band high-frequency signals are removed, removed parameter S ₃₁ is greater than the reflection parameter S _11. It can be seen that most of the frequency component removed from the input high-frequency signal is consumed by the load impedance 38 (FIG. 1B). Since the power of the resonance signal is transmitted to the load impedance 38 by the second transmission line 23, the power of the resonance signal does not stay in the resonance pattern 21.

  In this manner, the power of the resonance signal excited by the resonance pattern 21 can be immediately extracted to the outside. Further, the electric power extracted outside does not return to the resonance pattern 21. For this reason, the power durability of a dual mode resonator can be improved.

  When a simulation was performed when a high-frequency signal was input from the output end 22B of the first transmission line 22, the power of the reflected wave was larger than the power of the high-frequency signal extracted to the second transmission line 23. I understood. In order to reduce the reflected wave, it is preferable to input a high frequency signal from the input end 22 </ b> A of the first transmission line 22. Specifically, the traveling direction of the high-frequency signal transmitted along the first transmission line 22 is defined as a tangential vector that faces the second coupling position C2 among tangent vectors that pass through the first coupling position C1. The same orientation is preferred.

  In the first embodiment, the positions of the arcs cut at the first coupling position C1 and the second coupling position C2 are selected so that the central angle is 90 °. It does not have to be °. The second coupling position C <b> 2 may be set to a position where the power of the dual mode resonance signal excited by the resonance pattern 21 can be drawn out to the second transmission line 23. Further, the third coupling position C3 and the fourth coupling position C4 may be set to positions where the resonance pattern 21 can cause dual mode resonance.

  In particular, in the frequency band removed by the band elimination filter, the first coupling position C1 and the second coupling position C2 are set so that the power drawn to the second transmission line 23 is larger than the power of the reflected wave. Is preferably arranged. When arranged in this way, it becomes easy to perform impedance matching when a plurality of band elimination filters having the same configuration are arranged in multiple stages.

  FIG. 3 is a plan view of the conductive pattern of the band elimination filter according to the second embodiment. In the second embodiment, the band elimination filter has a two-stage configuration. Each of the first-stage and second-stage band elimination filters 50 and 51 has the same configuration as the band elimination filter according to the first embodiment except for the size of the conductive pattern.

  The first-stage band elimination filter 50 includes a first transmission line 55, a second transmission line 57, a first resonance pattern 58, and a third transmission line 59. The second-stage band elimination filter includes a first transmission line 55, a fourth transmission line 60, a second resonance pattern 61, and a fifth transmission line 62. The first transmission line 55 is shared by the first-stage band elimination filter 50 and the second-stage band elimination filter 51. The output terminal of the first transmission line 55 of the first-stage band elimination filter 50 is continuous with the input terminal of the first transmission line 55 of the second-stage band elimination filter 51.

  The resonance frequency of the second resonance pattern 61 is different from the resonance frequency of the first resonance pattern 58. For this reason, the transmission coefficient is small in the two bands near the resonance frequency of the first resonance pattern 58 and near the resonance frequency of the second resonance pattern 61.

FIG. 4A shows a block diagram of a transmitter using the band elimination filter according to the second embodiment. The first signal Sig ₀ is input to the power amplifier 70. The second signal Sig ₁ amplified by the power amplifier 70 is input to the band elimination filter 71. As the band elimination filter 71, the band elimination filter according to the second embodiment shown in FIG. 3 is used. The third signal Sig _{2 that} has passed through the band elimination filter 71 is sent to the antenna 72.

FIG. 4B shows the transmission parameter S ₂₁ of the band elimination filter 71. In two bands on both sides of a certain frequency f ₀ , the transmission parameter S ₂₁ is small. One valley of the transmission parameter S ₂₁ is due to the first-stage band elimination filter 50, and the other valley is due to the second-stage band elimination filter 51.

FIG. 4C shows an example of the spectrum of the first signal Sig ₀ input to the power amplifier 70. The first signal Sig ₀ has a frequency component in a certain band centered on the center frequency f ₀ .

FIG. 4D shows the spectrum of the second signal Sig ₁ amplified by the power amplifier 70. The non-linearity of the amplification characteristic of the power amplifier 70, on either side of the frequency band having the first signal Sig _0, noise component is generated. The transmission parameter S ₂₁ of the band elimination filter 71 shown in FIG. 4B is small in the band where the noise component is distributed.

FIG. 4E shows the spectrum of the third signal Sig ₂ that has passed through the band elimination filter 71. The noise component of the second signal Sig ₁ shown in FIG. 4D is removed by the band elimination filter. For this reason, the frequency band of the third signal Sig ₂ is substantially equal to the frequency band of the original first signal Sig ₀ .

The second signal Sig ₁ amplified by the power amplifier 70 is input from the input end of the first transmission line 55 of the first-stage band elimination filter 50 shown in FIG. 3, and the second-stage band elimination filter 51. To the output end of Only the noise component shown in FIG. 4D is extracted to the second transmission line 57 and the fourth transmission line 60 via the first resonance pattern 58 and the second resonance pattern 61. The power of the noise component is sufficiently smaller than the power (signal power) of the signal in the band of the original first signal Sig ₀ . That is, the power of the resonance signal excited by the first resonance pattern 58 and the second resonance pattern 61 is also small.

  For this reason, the power durability of the first and second resonance patterns 58 and 61 can be set smaller than the power of the high-frequency signal to be handled.

  The band elimination filter according to the third embodiment is obtained by modifying the conductive pattern of the band elimination filter according to the first embodiment shown in FIG. 1B.

  FIG. 5A is a plan view of the conductive pattern of the band elimination filter according to the third embodiment. In the first embodiment shown in FIG. 1B, the first transmission line 22 and the second transmission line 23 are curved at the coupling portion with the resonance pattern 21. In the first modification, both the first transmission line 22 and the second transmission line 23 are linear. For this reason, the degree of coupling between the first transmission line 22 and the resonance pattern 21 and the degree of coupling between the second transmission line 23 and the resonance pattern 21 are weaker than those in the first embodiment.

  Although the degree of coupling becomes weak, the point that the power of the signal drawn out to the second transmission line 23 is consumed by the load impedance 38 (FIG. 1B) is the same as in the case of the first embodiment. For this reason, the signal of the frequency band to be removed is suppressed from staying in the resonance pattern 21.

  FIG. 5B is a plan view of the conductive pattern of the band elimination filter according to the first modification of the third embodiment. The edge of the resonance pattern 21 is cut off in a straight line at a portion where it is coupled to the first transmission line 22 and the second transmission line 23. Each of the first transmission line 22 and the second transmission line 23 is linear, and is coupled to the resonance pattern 21 at a straight line portion of the resonance pattern 21.

  In the first modification, the length of the portion where the first transmission line 22 and the outer peripheral line of the resonance pattern 21 are parallel at a narrow interval can be set to the same level as in the first embodiment shown in FIG. 1B. For this reason, the degree of coupling between the first transmission line 22 and the resonance pattern 21 can be set to the same level as in the first embodiment. Similarly, the degree of coupling between the second transmission line 23 and the resonance pattern 21 can be set to the same level as in the first embodiment.

  FIG. 6A is a plan view of the conductive pattern of the band elimination filter according to the second modification of the third embodiment. In the second modification, the third transmission line 24 shown in FIG. 1B is eliminated, and a cutout 21 </ b> A is provided on the outer periphery of the resonance pattern 21 instead. The notch 21A is arranged at the center of the longer arc among the arcs having both ends of the first coupling position C1 and the second coupling position C2. By arranging the notch 21 </ b> A, the resonance pattern 21 can generate dual mode resonance.

  FIG. 6B is a plan view of the conductive pattern of the band elimination filter according to the third modification of the third embodiment. In the third modification, the third transmission line 24 shown in FIG. 1B is eliminated, and the planar shape of the resonance pattern 21 is changed from a circular shape instead. The resonance pattern 21 includes a semicircular portion 21B and an elliptical portion 21C. The semicircular portion 21B is formed by joining a sector having a central angle of 90 ° with the first coupling position C1 as the center of the arc and a sector having a central angle of 90 ° with the second coupling position C2 as the center of the arc. is there. The ellipse portion 21C is a part of an ellipse obtained by cutting an ellipse having a straight axis of the semicircular portion 21B as a short axis and a major axis in a direction orthogonal thereto.

  In this way, by changing the resonance pattern 21 from a circular shape, dual mode resonance can be generated.

  As shown in FIG. 5A to FIG. 6B, as a dual mode resonator used for a band elimination filter, a resonator including a disk-type resonance pattern and a dual mode generator for generating a dual mode resonance in the resonance pattern. Can be adopted. In the example shown in FIGS. 1B, 3, 5A, and 5B, the third transmission line 24 acts as a dual mode generator. In the example shown in FIG. 6A, the notch 21A acts as a dual mode generator. In the example shown in FIG. 6B, the planar shape itself of the disk-type resonance pattern acts as a dual mode generator.

  FIG. 7A shows a cross-sectional view of the band elimination filter according to the fourth embodiment. FIG. 7B is a plan sectional view taken along one-dot chain line 7B-7B in FIG. 7A. A cross-sectional view taken along one-dot chain line 7A-7A in FIG. 7B corresponds to FIG. 7A.

  As shown to FIG. 7A, the 1st supporting member 80 and the 2nd supporting member 82 penetrate the top plate 15B, and are hold | maintained so that raising / lowering is possible with respect to the top plate 15B. As the first and second support members 80 and 82, for example, screws that are screwed into through holes formed in the top plate 15B can be used. First and second dielectric members 81 and 83 are attached to lower ends (end portions in the package 15) of the first and second support members 80 and 82, respectively. Other configurations are the same as those of the bandpass filter according to the first embodiment shown in FIG. 1A.

  As shown in FIG. 7B, the first dielectric member 81 is disposed in the vicinity of the third coupling portion C3, and the second dielectric member 83 is disposed in the vicinity of the fourth coupling portion C4. Here, the “vicinity” can be defined as a range in which the influence of the electromagnetic field generated at the coupling portion between the resonance pattern 21 and the third transmission line 24 is affected. For example, in plan view, the first dielectric member 81 is disposed so as to overlap the third coupling portion C3, and the second dielectric member 83 is disposed so as to overlap the fourth coupling portion C4.

  By raising and lowering the first and second support members 80 and 82, the distance between the first and second dielectric members 81 and 83 and the dielectric substrate 20 can be changed. When the distance between the first and second dielectric members 81 and 83 and the dielectric substrate 20 changes, the coupling capacitance between the resonance pattern 21 and the third transmission line 24 changes. Thereby, the removal bandwidth of the band removal filter can be changed.

  FIG. 8 shows a cross-sectional view of the dielectric substrate and the conductive pattern of the band elimination filter according to the fifth embodiment. In the first embodiment, a microstrip line structure is used for the transmission line, but in the fifth embodiment, a strip line structure is used.

  A resonance pattern 21 and a first transmission line 22 are formed on the main surface of the dielectric substrate 20. Although not appearing in the cross section shown in FIG. 8, the second transmission line 23 and the third transmission line 24 shown in FIG. 1B are also formed on the main surface of the dielectric substrate 20. These conductive patterns have the same planar shape as the conductive pattern of the band elimination filter according to Example 1 shown in FIG. 1B.

  A ground film 27 is formed on the back surface of the dielectric pattern 20. A dielectric film 90 is disposed on the main surface of the dielectric substrate 20 so as to cover conductive patterns such as the resonance pattern 21 and the transmission line 22. Another ground film 91 is formed on the dielectric film 90.

  Thus, even if the stripline structure is adopted, the same effect as that of the microstripline structure of the first embodiment can be obtained.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

15 Package 20 Dielectric Substrate 21 Resonance Pattern 21A Notch 21B Semicircular Portion 21C Elliptical Portion 22 First Transmission Line 23 Second Transmission Line 24 Third Transmission Line 27 Ground Film 35 Input Connector 36, 37 Output Connector 38 Load Impedance 50 First-stage band elimination filter 51 Second-stage band elimination filter 55 First transmission line 57 Second transmission line 58 First resonance pattern 59 Third transmission line 60 Fourth transmission line 61 Second Resonance pattern 62 fifth transmission line 70 power amplifier 71 band elimination filter 72 antenna 80 first support member 81 first dielectric member 82 second support member 83 second dielectric member 90 dielectric film 91 ground film

Claims (6)

A dual mode resonator including a disk-shaped resonance pattern;
A first transmission line that passes outside the outer periphery of the resonance pattern and is electrically coupled to the resonance pattern;
And a second transmission line electrically coupled to the resonance pattern at a first end, and a resonance signal excited in the dual mode resonator by a signal transmitted through the first transmission line. A band elimination filter taken out to the second transmission line. The outer periphery of the resonance pattern includes a first portion having a circumferential shape,
The first transmission line and the second transmission line are electrically coupled to the resonance pattern in the first portion;
2. The band elimination filter according to claim 1, wherein the first transmission line and the second transmission line are curved so as to be parallel to the first portion at a coupling portion with the resonance pattern.   The first coupling position between the first transmission line and the resonance pattern and the second coupling position between the second transmission line and the resonance pattern are at both ends of an arc having a central angle of 90 °. The band elimination filter according to claim 2, which has a corresponding positional relationship.   The dual mode resonator further has one end capacitively coupled to the resonance pattern at a third coupling position on the outer periphery of the resonance pattern, and the other end at a fourth coupling position on the outer periphery of the resonance pattern. 4. The band elimination filter according to claim 1, further comprising a third transmission line that is capacitively coupled to the resonance pattern. 5. The dual mode resonator, the first transmission line, and the second transmission line are formed on a first surface of a dielectric substrate,
further,
A conductive ground film formed on a second surface opposite to the first surface of the dielectric substrate;
5. The band elimination filter according to claim 4, further comprising: a dielectric member disposed in the vicinity of at least one of the third coupling position and the fourth coupling position so that a distance from the dielectric substrate can be changed. .   The band elimination filter according to any one of claims 1 to 5, further comprising a load impedance that terminates the second transmission line and has an impedance that is the same as a characteristic impedance of the second transmission line.

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