JP4870737B2 - Dielectric resonator filter - Google Patents

Description

  The present invention relates to a dielectric resonator filter.

  In a cellular phone base station or the like, a resonator filter is used as a band-pass filter for defining a radio frequency band to be transmitted and received. In order to reduce the size of the base station, a reduction in the size of the resonator filter is required, and a dielectric resonator filter using a dielectric material as a resonator is used. In order to further reduce the size of the dielectric resonator filter, it has been proposed to use a multimode dielectric resonator (a plurality of resonance modes coexist in one dielectric resonator). For example, a technique of a filter configured by coupling a plurality of multimode dielectric resonators is disclosed (see Patent Document 1).

JP 2002-33605 A

Here, in order to effectively use the frequency range of wireless communication, there is a demand for narrowing the bandwidth of the dielectric resonator filter.
An object of the present invention is to provide a dielectric resonator filter with a narrow band.

  A dielectric resonator filter according to an aspect of the present invention includes a columnar or plate-shaped first conductor having a hollow outer conductor, a first bottom surface, and a first shaft disposed in the cavity. A dielectric resonator, a columnar or plate-like second dielectric resonator having a second bottom surface disposed in the cavity and facing the first bottom surface, and a second axis; A first notch disposed on the first dielectric resonator in a first direction as viewed from the first axis; and on the second dielectric resonator from the second axis. As seen, the second notch disposed in the second direction, the angle formed with the first direction being an integral multiple of a substantially right angle, and the end facing the side surface of the first dielectric resonator And a second signal terminal having an end facing the side surface of the second dielectric resonator.

  According to the present invention, it is possible to provide a dielectric resonator filter with a narrow band.

  Hereinafter, embodiments of the present invention will be described.

(First embodiment)
FIG. 1 is a perspective view of a dielectric resonator filter 100 according to the first embodiment of the present invention. 2 and 3 are plan views showing states of the upper and lower dielectric resonators 111 and 121 viewed from the direction of the axis Ax10, respectively.

  The dielectric resonator filter 100 functions as a band-pass filter that passes a signal in a desired frequency band, and includes an outer conductor 101, dielectric resonators 111 and 121, and signal terminals 14 and 15.

The outer conductor 101 is substantially cylindrical and has a cavity 102. For ease of viewing, the outer conductor 101 is represented by a virtual line (two-dot chain line).
In the present embodiment, the cavity 102 has a cylindrical shape. However, the cavity 102 may have another shape, for example, a prism shape. Note that the central axis of the cavity 102 preferably coincides with an axis Ax10 described later.
Since the outer conductor 101 is conductive, an electric field can be confined in the cavity 102. That is, the electric field leaking from the dielectric resonators 111 and 121 is confined in the cavity 102. As a result, the influence from the outside is cut off, and the characteristics of the dielectric resonator filter 100 are stabilized.

The dielectric resonators 111 and 121 are made of a columnar or plate-shaped dielectric material, and are arranged substantially coaxially (axis Ax10) in the cavity 102. That is, the centers C101 and C102 of the bottom surfaces (here, circular) of the dielectric resonators 111 and 121 substantially coincide with the axis Ax10.
In the present embodiment, the dielectric resonators 111 and 121 are cylindrical. However, an elliptical column shape or a prismatic shape may be adopted instead of the cylindrical shape. These dielectric resonators 111 and 121 are fixed to a support base made of alumina or the like (not shown).

  Each of the dielectric resonators 111 and 121 is sized so as to resonate in a double EH mode in a desired frequency band. That is, in the dielectric resonators 111 and 121, two resonance modes (EH1 and EH2 modes) in which the electric and magnetic fields are orthogonal to each other can coexist. As the dielectric resonators 111 and 121 as a whole, four vibrations can coexist.

  Here, the dielectric resonators 111 and 121 have substantially the same radius and height. As a result, the resonance modes in the dielectric resonators 111 and 121 have commonality (substantially the same resonance frequency). The dielectric resonators 111 and 121 make it possible to use four resonances (substantially four resonators) having substantially the same resonance frequency, so that the dielectric resonator filter 100 can be both reduced in size and narrowed in bandwidth. Becomes easy.

  The dielectric resonators 111 and 121 are electrically coupled by being arranged so that their bottom faces face each other. That is, a part of the resonance component of one of the dielectric resonators 111 and 121 is transmitted and contributes to the resonance in the other dielectric resonator 111 and 121. The strength of coupling between the dielectric resonators 111 and 121 can be adjusted by the distance between the dielectric resonators 111 and 121. Further, the strength of coupling may be adjusted by arranging studs and slots between the dielectric resonators 111 and 121. The stud is a rod-like body (for example, a cylinder or a prism) made of a conductive material. The slot is a slot disposed in the conductive plate member. That is, the arrangement of the slots between the dielectric resonators 111 and 121 means the arrangement of a plate member having the slots.

  Dielectric resonators 111 and 121 have notches 112 and 122, respectively. This notch is for coupling two resonance modes (EH1 and EH2 modes) in the dielectric resonators 111 and 121, respectively. When these notches 112 and 122 are not provided, the EH1 and EH2 modes in the dielectric resonators 111 and 121 are independent of each other. For example, even if the EH1 mode is excited in the dielectric resonator 111, the EH2 mode is not excited. On the other hand, when the notch 112 is present, the EH1 and EH2 modes are coupled in the dielectric resonator 111. For example, when the EH1 mode is excited in the dielectric resonator 111, the EH2 mode is also excited. The presence of the notches 112 and 122 causes conversion from one resonance mode (EH1, EH2 mode) component to the other resonance mode component (mode coupling).

The notches 112 and 122 are respectively disposed on the dielectric resonators 111 and 121 in directions A11 and A12 perpendicular to the axis Ax10 when viewed from the axis Ax10. The directions A11 and A12 can be defined with reference to the centers C11 and C12 (centers of gravity) of the surfaces S11 and S12 of the notches 112 and 122 (cross sections in which the dielectric resonators 111 and 121 are notched). The directions A11 and A12 can be defined by the angles θ11 and θ12 from the direction A10 perpendicular to the axis Ax10.
Here, it was found that the angle θ16 (= θ12−θ11) formed by the directions A11 and A12 when viewed from the axis Ax10 is an important factor in narrowing the bandwidth of the dielectric resonator filter 100. Specifically, the band of the dielectric resonator filter 100 can be narrowed by setting the angle θ16 to be an integer multiple of a substantially right angle. Details of this will be described later.

In the present embodiment, the surfaces S11 and S12 of the notches 112 and 122 have a planar shape (rectangular shape) having sides parallel to the left and right in FIG. However, other shapes can be employed as the surfaces S11 and S12. This is because mode coupling occurs in the dielectric resonators 111 and 121 without specifying the shapes of the notches 112 and 122 (surfaces S11 and S12). For example, the surfaces S11 and S12 can be curved surfaces. If the dielectric resonators 111 and 121 have the same shape and size, and the notches 112 and 122 have the same shape and size, the size of mode coupling in each of the dielectric resonators 111 and 121 is the same. be able to.
The notches 112 and 122 can be formed by polishing the dielectric resonators 111 and 121 along the axis Ax10 to the axis Ax10 by the depths H11 and H12.

Signal terminals 14 and 15 are terminals for inputting and outputting signals. Here, the signal terminals 14 and 15 are a signal input terminal and a signal output terminal, respectively.
The signal terminals 14 and 15 have end portions facing the side surfaces of the dielectric resonators 111 and 121. Signal terminals 14 and 15 are coupled to dielectric resonators 111 and 121 by an electric field, respectively. An electric field can be applied from the signal terminal 14 to the dielectric resonator 111 (input of a signal from the signal terminal 14 to the dielectric resonator filter 100). In addition, an electric field can be applied from the dielectric resonator 121 to the signal terminal 15 (output of a signal from the dielectric resonator filter 100 to the signal terminal 15).

  The signal terminals 14 and 15 are arranged in directions A14 and A15 perpendicular to the axis Ax10 from the axis Ax10 so as to face the side surfaces of the dielectric resonators 111 and 121, respectively. The directions A14 and A15 can be defined with reference to the centers of the ends of the signal terminals 14 and 15. The directions A14 and A15 can be defined by the angles θ14 and θ15 from the direction A10 perpendicular to the axis Ax10.

  The angles θ18 and θ19 (θ18 = θ14−θ11, θ19 = θ15−θ12) formed by the directions A14 and A15 of the signal terminals 14 and 15 and the directions A11 and A12 of the notches 112 and 122 are “approximately 45 ° ± 90”, respectively. It is preferable that it is "degree xn" (n: integer). In other words, the directions A14 and A15 of the signal terminals 14 and 15 and the directions A11 and A12 of the notches 112 and 122 are preferably not parallel or perpendicular. This is because the mode coupling in the dielectric resonators 111 and 121 can be increased by setting the directions A14 and A15 to the oblique directions of the directions A11 and A12. When the directions A14 and A15 are parallel and perpendicular to the directions A11 and A12, the resonance mode EH1 excited in the dielectric resonators 111 and 121 by the electric field from the signal terminals 14 and 15 is a resonance mode orthogonal to this. Virtually does not bind to EH2.

  The signal terminals 14 and 15 are arranged so as to form an angle φ (= θ15−θ14) that is an integral multiple of approximately 90 ° with respect to the axis Ax10. For example, the signal terminals 14 and 15 are arranged so as to be in substantially the same direction (substantially parallel) due to the wiring arrangement for signal input / output. Since the dielectric resonators 111 and 121 are resonated in the EH mode, the angle θ19 is an integral multiple of approximately 90 °.

  FIG. 4 is a circuit diagram showing an equivalent circuit of the dielectric resonator filter 100. Corresponding to the double EH mode in each of the dielectric resonators 111 and 121, the capacitive elements (capacitors) C111, C112, C121, and C122, and the inductance elements (coils) L111, L112, L121, and L122 are four resonators. (C111-L111, C112-L112, C121-L121, C122-L122). The resonators in the dielectric resonators 111 and 121 are coupled by capacitive elements C113 and C123. Capacitance elements C113 and C123 correspond to the notches 112 and 122, respectively.

  The capacitive element C14 corresponds to capacitive coupling between the signal terminal 14 and the dielectric resonator 111. The capacitive element C15 corresponds to capacitive coupling between the signal terminal 15 and the dielectric resonator 121. The capacitive element C16 corresponds to capacitive coupling between the dielectric resonators 111 and 121. That is, here, an example is shown in which the dielectric resonators 111 and 121 are coupled by a capacitor. If a slit is disposed between the dielectric resonators 111 and 121, the resonators 111 and 121 are inductively coupled, and the capacitive element C16 is replaced with the inductance element L16.

(Example)
The experimental results with the dielectric resonance filter 100 of the above embodiment will be described. In this experiment, the dielectric resonators 111 and 121 and the notches 112 and 122 were defined as follows.
-Constituent material of dielectric resonators 111 and 121: Calcium titanate (relative permittivity εr = 44)
-Diameters D11 and D12 of the dielectric resonators 111 and 121: 37 mm
-Lengths L11 and L12 of the dielectric resonators 111 and 121: 10 mm
-Depths H11 and H12 of the notches 112 and 122: 1.75 mm

The correspondence relationship between the angles (θ11, θ12, θ14, θ15) of the notches 112 and 122 and the signal terminals 14 and 15 and the characteristics of the dielectric resonator filter 100 was examined.
Tables 1, 2 and 5 to 8 show dielectric resonances when the angles (θ14, θ15) of the signal terminals 14, 15 are constant and the angles (θ11, θ12) of the notches 112, 122 are changed. The characteristics of the filter 100 are represented. 5 to 8, the vertical axis represents the intensity [dB] of the transmitted signal, and the horizontal axis represents the frequency [GHz].

  As shown in Tables 1 and 2, the samples G12, G14, G21, G23, G32, G34, G41, and G43 are more than the other samples (samples G11, G13, G22, G24, G31, G33, G42, and G44). The waveform became steep, and the band was narrowed by the attenuation pole. At this time, the absolute value of the difference θ16 (θ12−θ11) between the angles θ11 and θ12 was 90 °.

  As described above, the notches 112 and 122 are disposed in the dielectric resonators 111 and 121, and the absolute values of the directions A11 and A12 from the axis Ax10 toward the notches 112 and 122 are set to approximately 90 °. The band of the resonator filter 100 can be narrowed.

(Second Embodiment)
FIG. 9 is a perspective view of a dielectric resonator filter 200 according to the second embodiment of the present invention. 10 to 12 are plan views showing states of the upper, interrupted, and lower dielectric resonators 211 to 231 viewed from the direction of the axis Ax20.

  The dielectric resonator filter 200 functions as a band pass filter that passes a signal in a desired frequency band, and includes an outer conductor 201, partition walls 210 and 220, dielectric resonators 211 to 231, and signal terminals 24 and 25.

The outer conductor 201 is substantially cylindrical and has a cavity 202. For ease of viewing, the outer conductor 101 is represented by a virtual line (two-dot chain line).
In the present embodiment, the cavity 202 has a cylindrical shape. However, the cavity 202 may have another shape, for example, a prism shape. Note that the central axis of the cavity 202 preferably coincides with an axis Ax20 described later.

  The partition walls 210 and 220 divide the cavity 202 into three sections so that the dielectric resonators 211 to 231 are arranged in individual sections. Partitions 210 and 220 are formed with slots (not shown) for electrically coupling dielectric resonators 211 to 231.

The dielectric resonators 211 to 231 are made of a columnar or plate-like dielectric material, and are arranged substantially coaxially (axis Ax20) in the cavity 102. That is, the centers C201 to C203 of the bottom surfaces (here, circular) of the dielectric resonators 211 to 231 substantially coincide with the axis Ax10.
In the present embodiment, the dielectric resonators 211 to 231 have a cylindrical shape. However, an elliptical column shape or a prismatic shape may be adopted instead of the cylindrical shape. These dielectric resonators 211 to 231 are fixed to a support base made of alumina or the like (not shown).

  Each of the dielectric resonators 211 to 231 is sized so as to resonate in the double EH mode in a desired frequency band. That is, in the dielectric resonators 211 to 231, two resonance modes (EH1 and EH2 modes) in which the electric and magnetic fields are orthogonal to each other can coexist. As the dielectric resonators 211 to 231 as a whole, six vibrations can coexist.

  The dielectric resonators 211 to 231 are electrically coupled via the slots of the partition walls 210 and 220 by being disposed so that the bottom surfaces thereof face each other.

  Dielectric resonators 211 to 231 have notches 212 to 232, respectively. This notch is for coupling two resonance modes (EH1 and EH2 modes) in each of the dielectric resonators 211 to 231 (mode coupling).

  The notches 212 to 232 are arranged on the dielectric resonators 211 to 231 in directions A21 to A23 perpendicular to the axis Ax20 as viewed from the axis Ax20. The directions A21 to A23 can be defined with reference to the centers C21 to C23 (center of gravity) of the surfaces S21 to S23 (cross sections in which the dielectric resonators 211 to 231 are cut) of the notches 212 to 232. The directions A21 to A23 can be defined by the angles θ21 to θ23 from the direction A20 perpendicular to the axis Ax20.

In the present embodiment, the surfaces S21 to S23 of the notches 212 to 232 have a planar shape (rectangular shape) having sides parallel to the left and right in FIG. However, other shapes such as curved surfaces can be employed as the surfaces S21 to S23. This is because mode coupling occurs in the dielectric resonators 211 to 231 without specifying the shapes of the notches 212 to 232 (surfaces S21 to S23).
The notches 212 to 232 can be formed by polishing the dielectric resonators 211 to 231 to the axis Ax20 along the axis Ax20 by the depths H21 to H23.

The signal terminals 24 and 25 are terminals for inputting and outputting signals. Here, the signal terminals 24 and 25 are a signal input terminal and a signal output terminal, respectively.
The signal terminals 24 and 25 have end portions facing the side surfaces of the dielectric resonators 211 and 231. The signal terminals 24 and 25 are respectively coupled to the dielectric resonators 211 and 231 by an electric field.

  The signal terminals 24 and 25 are disposed in directions A24 and A25 perpendicular to the axis Ax20 from the axis Ax20 so as to face the side surfaces of the dielectric resonators 211 and 231, respectively. The directions A24 and A25 can be defined with reference to the centers of the ends of the signal terminals 24 and 25. The directions A24 and A25 can be defined by angles θ24 and θ25 from the direction A20 perpendicular to the axis Ax20.

  The angles θ28 and θ29 (θ28 = θ24−θ21, θ29 = θ25−θ22) formed by the directions A24 and A25 of the signal terminals 24 and 25 and the directions A21 and A23 of the notches 212 and 232 are “approximately 45 ° ± 90”. It is preferable that it is "degree xn" (n: integer).

  The signal terminals 24 and 25 are arranged so as to form an angle φ (= θ25−θ24) that is an integral multiple of approximately 90 ° with respect to the axis Ax20. For example, the signal terminals 24 and 25 are arranged so as to be substantially orthogonal due to the wiring arrangement for signal input / output.

  FIG. 13 is a circuit diagram showing an equivalent circuit of the dielectric resonator filter 200. Corresponding to the double EH mode in each of the dielectric resonators 211 to 231, capacitive elements (capacitors) C 211, C 212, C 221, C 222, C 231, C 232, inductance elements (coils) L 211, L 212, L 221, L 222, L231 and L232 constitute six resonators. The resonators in each of the dielectric resonators 211 to 231 are coupled by capacitive elements C213 to C233. Capacitance elements C213 to C233 correspond to the notches 212 to 232, respectively.

  The capacitive element C24 corresponds to capacitive coupling between the signal terminal 24 and the dielectric resonator 211. The capacitive element C25 corresponds to capacitive coupling between the signal terminal 25 and the dielectric resonator 231. The inductance elements L26 and L27 correspond to inductive coupling between the dielectric resonators 211 to 231 respectively. In this example, the dielectric resonators 211 to 231 are inductively coupled by the slots of the partition walls 210 and 220.

(Example)
An experimental result in the dielectric resonator filter 200 of the above embodiment will be described. In this experiment, the dielectric resonators 211 to 231 and the notches 212 to 232 were defined as follows.
-Constituent material of the dielectric resonators 211 to 231: calcium titanate (relative permittivity εr = 44)
-Diameters D21 to D23 of the dielectric resonators 211 to 231: 37 mm
-Length L21-L23 of dielectric resonators 211-231: 10 mm
-Depths of notches 212 to 232 H21 to H23: 1.75 mm

The correspondence relationship between the angles (θ11, θ12, θ14, θ15) of the notches 212 to 232 and the signal terminals 24 and 25 and the characteristics of the dielectric resonator filter 200 was examined.
14 and 15 respectively show dielectrics when the angles (θ21, θ22, θ23) of the notches 212 to 232 are (0 °, 0 °, 0 °) and (0 °, 0 °, 90 °). The characteristic of the resonator filter 200 is represented. The position of the attenuation pole is indicated by a downward arrow.

  In FIG. 14 and FIG. 15, two attenuation poles appear, and in particular, the waveform is steep in FIG. At this time, the difference θ26 (θ22−θ21) between the angles θ22 and θ21 and the difference θ27 (θ23−θ21) between the angles θ23 and θ21 were 0 ° and 90 °, respectively.

  As described above, the notches 212 to 232 are disposed in the dielectric resonators 211 to 231, and the angle differences θ25 and θ26 formed by the directions A21 to A23 from the axis Ax20 toward the notches 212 to 232 are respectively 0 °, By setting the angle to 90 °, the band of the dielectric resonator filter 200 can be narrowed.

(Modification)
Hereinafter, as a modification, the case where the shape of the dielectric resonance filter or the notch is changed in the first and second embodiments will be described. As shown below, even if these shapes are different, by appropriately defining the notch angle, it is possible to generate attenuation poles and narrow the band of characteristics.

A. Modification 1
The case where the shape of the notch of the dielectric resonance filter is changed in the first embodiment will be described. The dielectric resonator filter 100A in the modification (Modification 1) of the first embodiment of the present invention includes upper and lower dielectric resonators 111A and 121A. FIG. 16A and FIG. 16B are plan views showing a state in which the dielectric resonators 111A and 121A are viewed from the axial direction, respectively.

Here, the dielectric resonators 111A and 121A have notches 112A and 122A, respectively. In the first embodiment, the notches 112 and 122 have planar surfaces S11 and S12. In contrast, in the first modification, the notches 112A and 122A are substantially rectangular parallelepiped grooves each having a bottom surface and two side surfaces.
The dielectric resonator filter 100A is not substantially different from the dielectric resonator filter 100 except for the shape of the cutouts 112A and 122A, and the perspective view is omitted.

The experimental results in the first modification will be described. In this experiment, the dielectric resonators 111A and 121A and the notches 112A and 122A are defined as follows.
-Constituent material of dielectric resonators 111A and 121A: Calcium titanate (relative permittivity εr = 44)
-Diameters D11A and D12A of the dielectric resonators 111A and 121A: 37 mm
-Length L11A, L12A of dielectric resonators 111A, 121A: 10 mm
・ Depths of notches 112A and 122A H11A and H12A: 2.1 mm
・ Widths D11A and D12A of the notches 112A and 122A: 3.0 mm

  FIG. 17 shows a dielectric resonator filter 100A under the same angle conditions as G14 (θ11 = 0 °, θ12 = 270 °) and G41 (θ11 = 270 °, θ12 = 0 °) in Tables 1 and 2. Graphs GA1 and GA2 of FIG. The vertical axis of the graph of FIG. 17 represents the intensity [dB] of the transmitted signal, and the horizontal axis represents the frequency [GHz]. The graphs GA1 and GA2 almost overlap, and both have attenuation poles near 1.92 GHz (illustrated by arrows).

B. Modification 2
A case where the shape of the dielectric resonance filter is changed in the first embodiment will be described. The dielectric resonator filter 100B in the modification (Modification 2) of the first embodiment of the present invention includes upper and lower dielectric resonators 111B and 121B. 18A and 18B are plan views showing a state in which the dielectric resonators 111B and 121B are viewed from the axial direction, respectively.

Here, the dielectric resonators 111B and 121B have notches 112B and 122B, respectively. In the first embodiment, the dielectric resonators 111B and 121B are cylindrical. On the other hand, in the second modification, the dielectric resonators 111B and 121B each have a regular quadrangular prism shape.
The dielectric resonator filter 100B is not substantially different from the dielectric resonator filter 100 except for the shape of the dielectric resonators 111B and 121B, and a perspective view thereof is omitted.

The experimental results in the second modification will be described. In this experiment, the dielectric resonators 111A and 121A and the notches 112B and 122B are defined as follows.
-Constituent material of dielectric resonators 111B and 121B: Calcium titanate (relative permittivity εr = 44)
-Side lengths X11B and X12B of dielectric resonators 111B and 121B: 26 mm
-Length L11B, L12B of dielectric resonators 111B and 121B: 10 mm
・ Depths H11B and H12B of the notches 112B and 122B: 6 mm

  FIG. 19 shows a dielectric resonator filter 100B under the same angle conditions as G14 (θ11 = 0 °, θ12 = 270 °) and G41 (θ11 = 270 °, θ12 = 0 °) in Tables 1 and 2. Graphs GB1 and GB2 of FIG. The vertical axis of the graph of FIG. 19 represents the intensity [dB] of the transmission signal, and the horizontal axis represents the frequency [GHz]. Each of the graphs GB1 and GB2 has one and two attenuation poles in the vicinity of 2.06 GHz (illustrated by arrows).

C. Modification 3
A case where the shape of the notch of the dielectric resonance filter is changed in the second embodiment will be described. A dielectric resonator filter 200A according to a modification (Modification 3) of the second embodiment of the present invention includes dielectric resonators 211A to 231A.

Here, the dielectric resonators 211A to 231A have notches 212A to 232A, respectively. The notches 212A to 232A are substantially rectangular parallelepiped grooves each having a bottom surface and two side surfaces, as in the first modification.
The dielectric resonator filter 200A is not substantially different from the dielectric resonator filter 100A in points other than the number of dielectric resonators, and is not shown in the figure.

  The experimental result in the third modification will be described. In this experiment, each of the dielectric resonators 211A to 231A and the notches 212A to 232A is defined in the same manner as in the first modification.

  FIG. 20 shows a dielectric resonator filter 200A when the angles (θ21, θ22, θ23) of the notches 212 to 232 are (0 °, 0 °, 0 °) and (0 °, 0 °, 90 °). (Characters GC1, GC2). Graph GC1 has two attenuation poles near 1.75 GHz and 2.19 GHz, and graph GC2 has two attenuation poles near 1.86 GHz and 2.27 GHz (illustrated by arrows).

D. Modification 4
A case where the shape of the dielectric resonance filter is changed in the second embodiment will be described. The dielectric resonator filter 200B according to the modified example (modified example 4) of the second embodiment of the present invention includes dielectric resonators 211B to 231B. Dielectric resonators 211B to 231B have notches 212B to 232B, respectively.

Here, each of the dielectric resonators 211B to 231B has a regular quadrangular prism shape as in the second modification.
The dielectric resonator filter 200B is not substantially different from the dielectric resonator filter 100B in points other than the number of dielectric resonators, and thus illustration thereof is omitted.

  A description will be given of experimental results in the above-described modification example 4. In this experiment, the dielectric resonators 211B to 231B and the notches 212B to 232B are defined in the same manner as the second modification.

  21 shows dielectric resonator filters when the angles (θ21, θ22, θ23) of the notches 212 to 232 are (0 °, 0 °, 0 °) and (0 °, 0 °, 90 °), respectively. The characteristic (graph GD1, GD2) of 200C is represented. The graph GD1 has two attenuation poles near 1.78 GHz and 2.04 GHz, and the graph GD2 has two attenuation poles near 1.66 GHz and 2.07 GHz (illustrated by arrows).

(Other embodiments)
Embodiments of the present invention are not limited to the above-described embodiments, and can be expanded and modified. The expanded and modified embodiments are also included in the technical scope of the present invention.

  As described above, various shapes can be applied to the dielectric resonator and the notch. As shown in the above embodiment, a cylindrical resonator or a regular quadrangular prism can be used as the dielectric resonator. In addition, intermediate shapes such as an octagonal cylinder and an elliptic cylinder can be used. In addition to columnar shapes, plate shapes can also be used. As shown in the above embodiment, a flat plate shape or a groove shape can be used as the notch. It is also possible to use different shapes among the plurality of dielectric resonators. Electromagnetic coupling between dielectric resonators is greatly affected by studs or slots placed between dielectric resonators, and the shape of the dielectric resonator or notch itself has a large effect on electromagnetic coupling. It is not considered.

  Some width is recognized in the angle relation. For example, the angle θ16 (θ12−θ11) formed by the directions A11 and A12 of the notches 111 and 121 has a width of about ± 10 ° (preferably ± 5 °) around 90 °. The band of the dielectric resonator filter 100 can be narrowed in the range. Similar widths were observed for other angles.

It is a perspective view of the dielectric resonator filter in the 1st Embodiment of this invention. It is a top view which shows the dielectric resonator of an upper stage. It is a top view which shows the dielectric resonator of a lower stage. It is a circuit diagram which shows an example of the equivalent circuit of the dielectric resonator filter shown in FIG. It is a graph which shows an example of the electrical property of a dielectric resonator filter. It is a graph which shows an example of the electrical property of a dielectric resonator filter. It is a graph which shows an example of the electrical property of a dielectric resonator filter. It is a graph which shows an example of the electrical property of a dielectric resonator filter. It is a perspective view of the dielectric resonator filter in the 2nd Embodiment of this invention. It is a top view which shows the dielectric resonator of an upper stage. It is a top view which shows the dielectric resonator of a middle stage. It is a top view which shows the dielectric resonator of a lower stage. It is a circuit diagram which shows an example of the equivalent circuit of the dielectric resonator filter shown in FIG. It is a graph which shows an example of the electrical property of a dielectric resonator filter. It is a graph which shows an example of the electrical property of a dielectric resonator filter. 10 is a plan view showing an upper dielectric resonator in Modification 1. FIG. 10 is a plan view showing a lower dielectric resonator in Modification 1. FIG. 10 is a graph showing an example of electrical characteristics of a dielectric resonator filter in Modification 1. 10 is a plan view showing an upper dielectric resonator in Modification 2. FIG. 10 is a plan view showing a lower dielectric resonator in Modification 2. FIG. 10 is a graph showing an example of electrical characteristics of a dielectric resonator filter in Modification 2. 10 is a graph showing an example of electrical characteristics of a dielectric resonator filter in Modification 3. 14 is a graph showing an example of electrical characteristics of a dielectric resonator filter in Modification 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Dielectric resonator filter 101 Outer conductor 102 Cavity 111,121 Dielectric resonator 112,122 Notch 14,15 Signal terminal 200 Dielectric resonator filter 201 Outer conductor 202 Cavity 210,220 Bulkhead 211-231 Dielectric resonator 212,232 notches

Claims (5)

An outer conductor having a cavity;
A columnar or plate-like first dual mode dielectric resonator disposed within the cavity and having a first bottom surface and a first axis;
A columnar or plate-like second dual-mode dielectric resonator disposed in the cavity and having a second bottom surface facing the first bottom surface and a second axis;
A rectangular cross section disposed on the first dual-mode dielectric resonator in a first direction as viewed from the first axis and having a pair of sides along the first axis; 1 notch,
The second dual-mode dielectric resonator is disposed in a second direction in which an angle formed with the first direction when viewed from the second axis is an integer multiple of a substantially right angle , A second notch comprising a rectangular cross section having a pair of sides along a second axis ;
A first signal terminal having an end facing the side surface of the first dual-mode dielectric resonator;
A second signal terminal having an end facing the side surface of the second dual-mode dielectric resonator;
A dielectric resonator filter comprising:   2. The dielectric resonator filter according to claim 1, wherein a cross-sectional shape of at least one of the first and second dual mode dielectric resonators is a circular shape, an elliptical shape, or a polygonal shape.   The dielectric resonator filter according to claim 1, wherein the angle is substantially a right angle. A columnar third dual mode dielectric disposed between the first and second dual mode dielectric resonators and having third and fourth bottom surfaces respectively facing the first and second surfaces. A body resonator,
A third notch disposed on the third dual-mode dielectric resonator in a third direction as viewed from the third axis;
The dielectric resonator filter according to claim 1, further comprising: The angle formed by the direction of the first signal terminal and the direction of the first notch, and the angle formed by the direction of the second signal terminal and the direction of the second notch are “approximately 45 °. ± 90 ° * n ”(n: integer)
The dielectric resonator filter according to any one of claims 1 to 4, wherein the dielectric resonator filter is provided.

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