JPH11234008A - Dielectric resonator device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve no-load Q of a resonator and also to suppress the occurrence of undesired modes by forming the opening parts of the resonator into the slot shapes which extend up to one of both end faces of a dielectric plate. SOLUTION: Electrodes 2 and 3, having the opening parts 4 and 5 of slot shapes opposite to each other, are formed on both main sides of a dielectric plate 1. Thus, the plate 1 having the parts 4 and 5 opposite to each other partly functions as a dielectric resonator. Probes 9 and 10 are placed at the height almost equal to that of the plate 1 and protrude from the center conductor of a coaxial connector, for example, and also the conductor sides 6 and 7 which are equally separated from the plate 1 are provided on the top and under surfaces of the plate 1. A space ta that is set between both sides 6 and 7 and both electrodes 2 and 3 is required for attenuating the resonance frequency signal of the dielectric resonator. Therefore, no electromagnetic wave is propagated in a space formed between the sides 6 and 7 and the electrodes 2 and 3, and thus energy is confined at the parts 4 and 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric resonator device used in a microwave band or a millimeter wave band.

[0002]

2. Description of the Related Art Conventionally, in response to a demand for miniaturization of a dielectric resonator device such as a dielectric filter, for example, the Institute of Electronics, Information and Communication Engineers, 1996, General Meeting C-121, “Quasi-Finally Using Planar Circuit Type Dielectric Resonator Planar-circuit-type dielectric resonator devices such as "millimeter-wave band-pass filter" and Japanese Patent Application No. 9-101458 "planar-circuit-type dielectric resonator device" have been developed.

In the planar circuit type dielectric resonator, electrodes having circular openings facing each other are provided on both main surfaces of a dielectric plate, and these electrodes are arranged between two conductor surfaces. In addition, a probe is provided to constitute a dielectric resonator device.

A part of the dielectric plate sandwiched between the electrode openings acts as a dielectric resonator, and adjacent dielectric resonators are coupled with each other, and each dielectric resonator is coupled with the probe.

[0005]

In such a conventional planar circuit type dielectric resonator device, since a magnetic field concentrates near the electrode opening, current concentration occurs in that portion, and Q
o (no-load Q). Also,
Since the excitation probe was placed in the air layer below the dielectric plate that constituted the resonator, the upper and lower structures centered on the dielectric plate became asymmetric, which also caused unnecessary resonance modes. .

An object of the present invention is to provide a dielectric resonator device in which the Qo of the resonator is increased.

Another object of the present invention is to provide a dielectric resonator device using a planar circuit type dielectric resonator in which generation of an unnecessary mode is suppressed.

[0008]

SUMMARY OF THE INVENTION The present invention provides a resonator having a Q
2. A dielectric resonator in which electrodes having openings facing each other are provided on both main surfaces of a dielectric plate as described in claim 1, in order to increase o, and both main surfaces of the dielectric plate are provided. A dielectric resonator device having two conductor surfaces separated from each other, wherein the opening is formed in a slot shape extending to at least one end surface of the dielectric plate.

According to this structure, there is almost no electrode in the portion where the magnetic field is concentrated, and the number of portions where the surface current of the electrode is concentrated is greatly reduced. As a result, the entire current loss is suppressed, and a decrease in Qo of the resonator is suppressed.

In the case where the plurality of dielectric resonators are coupled, as described in claim 2, a plurality of dielectric resonators are arranged with the end faces of the dielectric plate extending the opening facing each other. By coupling a plurality of dielectric resonators in this way, for example, a bandpass filter in which a plurality of resonators are sequentially coupled can be configured.

According to a third aspect of the present invention, when a dielectric member is interposed at a position where the end surfaces of the dielectric plate where the opening extends extend, the dielectric member is interposed by the effective dielectric constant of the dielectric member. Since the degree of coupling between the two dielectric resonators sandwiching the body member changes, the degree of coupling can be set by partially piercing the dielectric member.

Further, the present invention is to suppress the occurrence of an unnecessary resonance mode due to the positional relationship between conductor surfaces above and below a dielectric plate constituting a dielectric resonator and excitation means such as a probe coupled to the dielectric resonator. The distance between both main surfaces of the dielectric plate and the two conductor surfaces is substantially equal to each other, and the exciting means for electromagnetically coupling with the dielectric resonator is provided with the two conductors. A symmetrical structure centered on a substantially central position between the surfaces. With this structure, the propagation of the unnecessary resonance mode in which the electric field distribution is directed between the two conductor surfaces is canceled by the symmetry.

Here, suppression of the unnecessary resonance mode will be described. FIG. 13 shows two examples in which a coaxial probe is selected as an excitation method and excitation positions are different.
(A) shows the case where the excitation position is selected at the center height of the dielectric plate 1, and (B) shows the case where the excitation position is selected at a position deviated from the center height of the dielectric plate 1. In the case of (A), an electric field as shown in the figure is generated between the excitation probe and the upper and lower electrodes on the dielectric plate. This electric field easily couples with an unnecessary resonance mode in which the electric field distribution is directed between the two conductor surfaces. However, when the excitation probe is arranged at the center of the dielectric plate, the electric field a generated between the excitation probe and the upper electrode 2 and the electric field b generated between the lower electrode 3 have opposite phases. Unnecessary resonance modes are suppressed because they are equal in magnitude and cancel each other. As a result, a dielectric resonator device with less spurious is obtained. On the other hand, in the case of FIG. 13B, the generated electric fields a ′ and b ′ have different magnitudes, so that the electric fields a ′ and b ′ are not canceled out and propagate in an unnecessary mode.

The above-mentioned excitation means can be constituted by a strip line probe. Further, as described in claim 6, a dielectric strip may be provided between two conductor surfaces to be provided as a non-radiative dielectric line.

Further, since each of the dielectric resonators can be formed on a separate dielectric plate, a predetermined one of the plurality of dielectric resonators can be used as a dielectric resonator. An input / output duplexer such as an antenna duplexer can be configured by providing an excitation unit at a coupling position and forming an input unit, an output unit, and an input / output unit of a signal.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a dielectric filter according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1A is a perspective view of a dielectric filter,
(B) is a sectional view thereof. In this figure, reference numeral 1 denotes a dielectric plate, and electrodes 2 and 3 having slot-shaped openings 4 and 5 facing each other are formed on both main surfaces thereof. With this structure, a part of the dielectric plate facing the slot-shaped openings 4 and 5 functions as a dielectric resonator. Reference numerals 9 and 10 denote probes provided at substantially the same height as the dielectric plate 1 and protrude from the center conductor of the coaxial connector, for example.
On the upper and lower surfaces of the dielectric plate 1 in the figure, two conductor surfaces 6 and 7 which are equally spaced from the dielectric plate 1 are provided.

The distance ta between the conductor surfaces 6, 7 and the electrodes 2, 3 on the surface of the dielectric plate 1 is a distance required to attenuate the resonance frequency signal of the dielectric resonator. That is, the cutoff frequency is set to be higher than the resonance frequency of the dielectric resonator. Therefore, no electromagnetic wave propagates in the space between the conductor surfaces 6 and 7 and the electrodes 2 and 3, and energy is confined in the electrode openings 4 and 5. as a result,
Radiation loss is suppressed, and a decrease in Qo is suppressed.

FIG. 2 is a diagram showing an electromagnetic field distribution in a cross section of the dielectric filter shown in FIG. In the figure, the solid line is the electric field,
The broken lines indicate the distribution of the magnetic field, respectively. As described above, the dielectric resonator has a magnetic field loop surface in the direction in which the slot of the slot-shaped opening extends, and is magnetically coupled to the probes 9 and 10, respectively. When the resonance space is divided into a region A and a region B in FIG. 2, the electromagnetic field energy also exists in the region B. Therefore, the magnetic field does not concentrate on the region of the dielectric plate 1 where the electrodes exist, and no conductor loss occurs at that portion. Therefore, Qo of the resonator does not decrease.

FIG. 3 is a sectional view showing a more specific example of the structure of the dielectric filter having the structure shown in FIGS. Reference numerals 11 and 12 denote conductor cases for holding the dielectric plate 1 at predetermined positions, and their inner surfaces serve as conductor surfaces facing the dielectric resonator. With this structure, the dielectric plate can be arranged at the center of the two upper and lower conductor surfaces. In the probes 9 and 10 shown in FIG. 1, the coaxial connectors with the excitation probes protruding may be attached to the side surfaces of the conductor case 12 so that the probes are located at the center in the height direction in the conductor case. .

Next, the total length of the dielectric filter and the unloaded Q
FIG. 4 shows the relationship between (Qo) and the relationship between the length of the dielectric plate and the entire length of the dielectric filter. Here, the resonance frequency of the dielectric resonator is 30 GHz, and the relative permittivity of the dielectric plate is 24.
The dimensions of each part shown in FIG. 1 are td = 1.0 mm, t
a = 0.8 mm and w = 0.8 mm. The electrodes 2 and 3 are Au electrodes.

In FIG. 4, the dielectric filter shown in FIG. 1 is shown as "both ends open type". For comparison, a dielectric resonator provided with electrodes having rectangular openings facing each other on both main surfaces of the dielectric plate is shown as "both-end short-circuit type". Here, the total length and the length of the dielectric plate correspond to L1 and L0 shown in FIG. 1, respectively.

[0023] Factors for reducing the no-load Q mainly include conductor loss, dielectric loss, and radiation loss. Among them, the conductor loss is dominant in the planar dielectric waveguide resonator as in the present application. The conductor loss is proportional to the Joule loss, and the Joule loss is proportional to the square of the current. Therefore, even if the total amount of current flowing through the electrode portion is the same, if the current concentration occurs, the Joule loss increases accordingly, and the no-load This leads to a decrease in Q. In the case of open ends,
As the total length L of the dielectric filter is increased, the concentration of the magnetic field is reduced, and as shown in FIG.
Increase. On the other hand, in the case of the both-end short-circuit type, the no-load Q is determined by the conductor loss at the short-circuited portion, and a high no-load Q cannot be obtained even if the overall length is increased.

If the entire length is the same, the dielectric plate length can be shorter in the open-ended type than in the short-ended type.
The reason will be described below.

First, FIG. 12 shows an example of an electromagnetic field distribution of a dielectric resonator having both ends short-circuited. When the resonance space is divided into the region A and the region B in FIG. 12, electromagnetic field energy hardly exists in the region B. On the other hand, in the case of the open-ended dielectric resonator shown in FIG. In particular, the leakage energy into the region B of the resonator is dominated by the magnetic field energy. The resonance frequency is determined by the electric field energy and the magnetic field energy, and according to the perturbation theory, it is known that a decrease in the magnetic field energy leads to a decrease in the resonance frequency. for that reason,
When the open-ended resonator is compared with a short-ended resonator having the same length, the resonant frequency of the open-ended resonator is lower than that of the open-ended resonator, which almost completely confines energy, due to the leakage of the magnetic field. . Since the lower frequency can be corrected by shortening the length of the dielectric plate, if the length of the dielectric plate is selected so that the resonance frequency is the same for both open-ended type and short-ended type, Of course, the length is shorter in the open-ended type.

Next, the configuration of a dielectric filter according to a second embodiment is shown in FIG. Here, three dielectric plates each provided with a dielectric resonator are used. In FIG.
Reference numerals a, 8b, and 8c denote dielectric resonators, each of which forms an electrode provided with slot-shaped openings facing each other on both main surfaces of the dielectric plate. 4 is a slot-shaped opening on the upper surface. Then, adjacent dielectric plates are arranged such that the end surfaces of the dielectric plates extending the slot-shaped openings face each other, and a spacer made of a dielectric member (hereinafter referred to as a “dielectric spacer”) 13 is provided at the facing position. Is interposed. Then, probes 9 and 10 are provided to be coupled to the dielectric resonators 8a and 8c on both sides, respectively.

FIG. 5B is a diagram showing a state of coupling between dielectric resonators, and a broken line shows a magnetic field distribution. In this way, adjacent dielectric resonators are magnetically coupled with each other,
Since the dielectric spacer 13 is provided on the way, by forming a coupling adjusting hole 14 in the dielectric spacer 13 to adjust the effective dielectric constant of the dielectric spacer 13,
The degree of coupling between adjacent dielectric resonators can be set.

FIG. 6 is a partially broken schematic perspective view showing the structure of the dielectric filter according to the third embodiment. In the figure, reference numerals 15 and 17 denote dielectric plates, respectively, on one main surface of which strip conductors 16 and 18 are formed, respectively. These strip conductors 16 and 17 are located at a central position between upper and lower conductor surfaces. It is arranged so that it becomes. The strip conductors 16 and 17, the dielectric plates 15 and 17, and the upper and lower conductor surfaces form probes with suspended lines, respectively. The structure of the dielectric resonator 8 is the same as that of the first and second embodiments, and is arranged at the center between the upper and lower conductor surfaces. Therefore, the probe is magnetically coupled to the dielectric resonator 8.

FIG. 7 is a partially cutaway perspective view showing the structure of a dielectric filter according to a fourth embodiment. Unlike the case of FIG. 6, here, the dielectric plates 15 and 17 provided with the strip conductors 16 and 18 are laminated on the dielectric plate of the dielectric resonator 8. Even in such a case, the dielectric plate 1
By reducing the thickness of the strip conductors 5 and 17, the strip conductors 16 and 18 can be arranged at the center between the upper and lower conductor surfaces, and the occurrence of unnecessary modes is suppressed.

FIG. 8A is a partially cutaway schematic perspective view showing the structure of a dielectric filter according to a fifth embodiment.
(B) is a cross-sectional view passing through the slot-shaped electrode opening. In this example, electrodes 2 and 3 having slot-shaped openings 4 and 5 facing each other are provided on both main surfaces of the dielectric plate 1. The slot-shaped openings 4 and 5 extend only to one end face of the dielectric plate 1, and the other end face facing the end face forms a continuous electrode with the upper and lower electrodes 2 and 3 and serves as a short-circuit face. I have. In the case of such a one-side open dielectric resonator, a magnetic field is distributed as shown in FIG. Therefore, an exciting means such as the probe 9 is provided at a position facing the end face of the dielectric plate where the slot-shaped opening extends, thereby coupling with the dielectric resonator. This dielectric filter can be used, for example, as a trap for attenuating the resonance frequency of a dielectric resonator.

FIGS. 9A and 9B are views showing the configuration of a dielectric filter according to a sixth embodiment, in which FIG. 9A is a partially cutaway schematic perspective view, and FIG. It is sectional drawing in the surface perpendicular | vertical to a board. In this example, three dielectric resonators are formed by providing slot-shaped openings 4a, 5a, 4b, 5b, 4c and 5c facing each other on both main surfaces of a single dielectric plate 1, respectively. doing. The magnetic field distribution of each resonator is as shown in (B) of the figure, and the adjacent resonators are magnetically coupled, and the resonators on both sides are magnetically coupled to the probes 9 and 10, respectively. With this structure, a band-pass filter including a three-stage resonator can be obtained while using a single dielectric plate.

FIGS. 10A and 10B are views showing the structure of a dielectric filter according to a seventh embodiment, in which FIG. 10A is a partially cutaway schematic perspective view of a main part thereof, and FIG. 10B is a sectional view thereof. 19, 2
Numeral 0 denotes a dielectric strip disposed between the conductor plates forming the upper and lower conductor surfaces 6 and 7, respectively. The dielectric strips 19 and 20 and the upper and lower conductor surfaces 6 and 7 provide a non-radiative dielectric line (NRD guide). Is composed. The dielectric resonator 8 is disposed at a position sandwiched between the end faces of the dielectric strips 19 and 20. The dielectric resonator 8 is an open-ended dielectric resonator in which electrodes having slot-shaped openings facing each other are provided on both main surfaces of a dielectric plate. Are arranged in parallel with the conductor surfaces 6 and 7 at substantially the center position of. The electromagnetic field distribution of the dielectric resonator and the NRD guide is shown in FIG.
And the NRD guide and the dielectric resonator are magnetically coupled. With this structure, the dielectric resonator 8 has NR
It acts as a bandpass filter inserted in the middle of the D guide.

FIG. 11 is a partially broken schematic perspective view showing the structure of a dielectric resonator device according to an eighth embodiment. FIG.
Although the NRD guide is used as the transmission line and the input / output part of the dielectric resonator in the example of FIG. 11, in the example shown in FIG. 11, the planar dielectric line (so-called PDTL) is used as the input / output part of the transmission path and the dielectric resonator. Used as (The applicant is P
A Japanese Patent Application No. 7-69867 has been applied for DTL. That is, an electrode having a slot-shaped opening facing each other is provided on each of both main surfaces of the dielectric plates 21 and 22 to form a planar dielectric line (PDTL). The dielectric resonator 8 is positioned between the two PDTLs.
Has been arranged. The PDTL and the dielectric resonator 8 are arranged substantially at the center between the upper and lower conductor planes and parallel to the conductor planes. With this structure, the PDTL and the dielectric resonator are also magnetically coupled, and a dielectric resonator device having a structure in which a dielectric resonator as a filter is inserted in the middle of the PDTL is obtained.

[0034]

According to the first aspect of the present invention, since the electrode opening has a slot shape extending to at least one end face of the dielectric plate, there is almost no electrode in a portion where the magnetic field is concentrated, and the surface of the electrode is The number of places where current concentrates is greatly reduced. As a result, the overall current loss is suppressed, and the Qo of the resonator is reduced.
Is suppressed.

According to the second aspect of the present invention, for example, a band-pass filter or the like in which a plurality of resonators are sequentially coupled can be easily configured.

According to the third aspect of the invention, the degree of coupling can be easily set by partially piercing the dielectric member.

According to the fourth aspect of the present invention, the propagation of the unnecessary resonance mode between the two conductor surfaces is cancelled, and a dielectric resonator with less spurious is obtained.

According to the fifth aspect of the present invention, since the excitation means can be constituted by the line on the dielectric plate, it can be easily provided in the conductor case together with the dielectric resonator.

According to the sixth aspect of the present invention, a dielectric filter can be easily provided in a high-frequency circuit using a non-radiative dielectric line.

According to the invention of claim 7, an input / output duplexer such as an antenna duplexer can be easily configured.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view and a sectional view showing a configuration of a dielectric filter according to a first embodiment.

FIG. 2 is a diagram showing an example of an electromagnetic field distribution of the dielectric filter.

FIG. 3 is a cross-sectional view showing a specific configuration example of the entire dielectric filter.

FIG. 4 is a diagram showing a relationship between dimensions of the dielectric filter according to the first embodiment and unloaded Q and the like;

FIG. 5 is a partially cutaway schematic perspective view and a sectional view of a dielectric filter according to a second embodiment.

FIG. 6 is a partially cut-away schematic perspective view of a dielectric filter according to a third embodiment.

FIG. 7 is a partially cutaway schematic perspective view of a dielectric filter according to a fourth embodiment.

FIG. 8 is a partially cutaway schematic perspective view and a sectional view of a dielectric filter according to a fifth embodiment.

FIG. 9 is a partially cutaway schematic perspective view and a sectional view of a dielectric filter according to a sixth embodiment.

FIG. 10 is a partially cutaway schematic perspective view and a sectional view of a dielectric filter according to a seventh embodiment.

FIG. 11 is a schematic perspective view, partly broken away, of a dielectric filter according to an eighth embodiment.

FIG. 12 is a diagram showing an example of an electromagnetic field distribution of a dielectric filter using a both-end short-circuit type dielectric resonator.

FIG. 13 is a diagram showing a positional relationship between a probe as an excitation unit and a dielectric resonator, and a relationship with an unnecessary mode.

[Explanation of symbols]

 Reference Signs List 1-dielectric plate 2,3-electrode 4,5-slot opening 6,7-conductor surface 8-dielectric resonator 9,10-probe 11,12-case 13-dielectric spacer 14-coupling adjustment Holes 15, 17-Dielectric plate 16, 18-Strip conductor 19, 20-Dielectric strip 21, 22-Dielectric plate 23, 24-Electrode

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiro Hiratsuka 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd.

Claims (7)

[Claims] 1. A dielectric resonator in which electrodes having openings facing each other are provided on both main surfaces of a dielectric plate, respectively.
A dielectric resonator device comprising two conductor surfaces separated from both main surfaces of the dielectric plate, wherein the opening is formed in a slot shape extending to at least one end surface of the dielectric plate. A dielectric resonator device characterized in that: 2. The dielectric plate according to claim 1, wherein the end faces of the dielectric plate extending from the opening face each other, a plurality of the dielectric resonators are arranged, and the plurality of dielectric resonators are coupled. 2. The dielectric resonator device according to 1. 3. The dielectric resonator device according to claim 2, wherein a dielectric member is interposed between opposing end surfaces of the dielectric plate extending from the opening. 4. An apparatus according to claim 1, wherein the distance between the two main surfaces of the dielectric plate and the two conductor surfaces is substantially the same, and an exciting means for electromagnetically coupling with the dielectric resonator is provided between the two conductor surfaces. The dielectric resonator device according to any one of claims 1 to 3, wherein the dielectric resonator device has a symmetric structure centered on a center position. 5. The dielectric resonator device according to claim 4, wherein said excitation means is a probe using a strip line formed on a dielectric plate. 6. The dielectric resonator device according to claim 4, wherein said excitation means is a non-radiative dielectric line having a dielectric strip disposed between said two conductor surfaces. 7. The signal input section, wherein the excitation means according to any one of claims 4 to 6 is provided at a position coupled to a predetermined dielectric resonator among the plurality of dielectric resonators. An input / output duplexer comprising an output unit and an input / output unit.