JPH06334411A - Coaxial dielectric resonator - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a coaxial dielectric resonator excellent in mass productivity, durability, and reliability that can be miniaturized with low loss without changing the diameter of the hollow portion. To do. A hollow dielectric 1, an outer conductor 4 formed on the outer circumference of the hollow dielectric 1, an inner conductor 5 formed in a hollow portion 2 of the hollow dielectric 1, and a hollow dielectric 1 A quarter-wave coaxial dielectric resonator having a short-circuit conductor 6 for electrically connecting the outer conductor 4 and the inner conductor 5 formed on one end surface of the outer conductor 4, wherein the short-circuit conductor 6 of the outer conductor 4 is At least one outer peripheral side electrode 8 formed inside the open end 7 that is not formed, and the outer peripheral side electrode 8 formed outside the open end 7 of the inner peripheral conductor 5 and the hollow dielectric 1 are provided. It is configured to include at least one inner circumferential side electrode 9 that serves as the capacitance portion A and faces each other with the capacitor 9 interposed therebetween.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial type dielectric resonator used in radio communication equipment and the like, and particularly preferably used in a high frequency band from VHF to SHF.

[0002]

2. Description of the Related Art In recent years, coaxial type dielectric resonators have been widely used as band pass filters and band stop filters in a high frequency band in wireless communication devices and the like. The container has also been miniaturized as disclosed in, for example, Japanese Patent Application Laid-Open No. 58-95403.

A conventional coaxial dielectric resonator will be described below. FIG. 6A is a plan view of a conventional coaxial dielectric resonator, and FIG. 6B is a vertical cross-sectional view of the conventional coaxial dielectric resonator. Reference numeral 1 is a hollow dielectric body, 2 is a hollow portion of the hollow dielectric body 1, 3 is a stepped portion formed by changing the diameter of the hollow portion 2, and 4 is a peripheral conductor formed on the outer circumference of the hollow dielectric body 1. Reference numeral 5 denotes an inner peripheral conductor formed on the inner peripheral surface of the hollow portion 2 of the hollow dielectric body 1, and 6 is formed on one end portion of the hollow dielectric body 1 to electrically connect the outer peripheral conductor 4 and the inner peripheral conductor 5. The short-circuit conductor, 7 is an open end where the hollow dielectric 1 is exposed.

The operation of the conventional coaxial dielectric resonator configured as described above will be described below. In general,
Assuming that the coaxial outer diameter of the coaxial dielectric resonator is D1, the inner diameter of the hollow portion is D2, and the permittivity of the hollow dielectric material is Er, the characteristic impedance Z ₀ is represented by the following equation.

Z₀= 60 · ln (D1 / D2) / √Er Line having a length L1 close to the short-circuit conductor 6 of the coaxial dielectric resonator
Impedance of Z ₀₁, A line of length L2 close to the open end 7
Z of the path impedance₀₂Then, the resonance condition is
Is represented as

Tan βL1 · tan βL2 = tan θ ₁ · tan θ ₂ = Z ₀₁ / Z ₀₂ where β is a phase constant and θ ₁ and θ ₂ are electrical lengths.
Now, for the sake of simplicity, considering the case of L1 = L2, that is, θ ₁ = θ ₂ , this resonance condition is expressed as follows.

Tan ² θ = Z ₀₁ / Z ₀₂ = K where θ = θ ₁ = θ ₂ and K is the impedance ratio. From this, the resonator length L is expressed by the following relationship.

L = 2 (tan ⁻¹ √K) / β As is clear from this equation, the smaller the impedance ratio K, the shorter the resonator length L, and the size of the coaxial dielectric resonator can be reduced. it can. Here, as for the impedance ratio K, the diameter of the hollow portion 2 on the open end 7 side is D1, the diameter of the hollow portion 2 on the short-circuit conductor 6 side is D2, and the outer diameter of the hollow dielectric body 1 is D3.
Then, it can be expressed as follows.

[0009]

[Equation 1]

As is clear from this (Equation 1), in order to reduce the impedance ratio K in order to reduce the size of the coaxial dielectric resonator, if the outer diameter D3 is constant, the open end of the hollow portion 2 is reduced. The diameter D1 on the 7 side may be reduced, or the diameter D2 on the short-circuit conductor side of the hollow portion 2 may be increased.

[0011]

However, in the above-mentioned conventional structure, if the diameter D1 on the open end side of the hollow portion is reduced in order to reduce the impedance ratio K in order to downsize the coaxial dielectric resonator, There has been a problem that the area of the peripheral conductor is reduced, the resistance is increased, the Q value of the coaxial dielectric resonator is significantly reduced, the characteristics are deteriorated, and the reliability is deteriorated. Further, it is extremely difficult to form a hole having a small diameter in the hollow dielectric body and to attach an inner peripheral conductor to the hollow portion, and there is a problem that the yield is reduced and the mass productivity is poor. On the other hand, when the inner diameter D2 of the hollow portion on the short-circuit conductor side is increased, the thickness of the hollow dielectric body between the inner and outer conductors is reduced, so that the mechanical strength and yield of the coaxial dielectric resonator are reduced. However, there is a problem in that durability and mass productivity are deteriorated.

The present invention solves the above-mentioned conventional problems, and is a coaxial type dielectric excellent in mass productivity, durability, and reliability, which can be miniaturized with low loss without changing the diameter of the hollow portion. An object is to provide a body resonator.

[0013]

In order to achieve this object, a coaxial dielectric resonator according to a first aspect of the present invention is formed with a hollow dielectric and an outer periphery of the hollow dielectric. An outer peripheral conductor, an inner peripheral conductor formed in the hollow portion of the hollow dielectric, a short-circuit conductor that conducts the outer peripheral conductor and the inner peripheral conductor formed on one end surface of the hollow dielectric, A quarter-wave coaxial dielectric resonator comprising: at least one outer peripheral electrode formed inside the outer peripheral conductor in the vicinity of an open end where the short-circuit conductor is not formed, A structure having at least one inner peripheral side electrode that is formed outside the inner peripheral conductor in the vicinity of the open end and faces the outer peripheral side electrode via the hollow dielectric and serves as a capacitance section. The coaxial dielectric resonator according to claim 2 is hollow. A coaxial dielectric resonance for 1/2 wavelength including an electric body, an outer peripheral conductor formed on the outer periphery of the hollow dielectric body, and an inner peripheral conductor formed in the hollow portion of the hollow dielectric body And at least one outer peripheral side electrode formed inside at least one end of the outer peripheral conductor, and the outer peripheral side electrode formed at the outer side near at least one end of the inner peripheral conductor and the hollow shape It has a configuration including at least one or more inner circumferential side electrodes that face each other via a dielectric and serve as a capacitance section.

[0014]

With this structure, at least one pair of outer peripheral electrodes, which are electrically connected to the outer peripheral conductor, are provided in the vicinity of at least one open end of the hollow dielectric, and are opposed to the outer peripheral electrodes via the hollow dielectric. By arranging the inner peripheral side electrode and the inner peripheral side electrode electrically connected to each other, since the outer peripheral side electrode and the inner peripheral side electrode form a capacitance, by increasing the electrostatic capacitance, The resonator length can be reduced without changing the diameter of the portion, and the coaxial dielectric resonator can be downsized. Further, since this capacitor is a laminated structure capacitor integrally formed in the hollow dielectric body, the coaxial dielectric resonator can be further downsized. Further, since it is not necessary to change the diameter of the hollow portion for downsizing, manufacturing can be facilitated, mechanical strength can be improved, and loss can be reduced.

[0015]

EXAMPLE 1 A coaxial type dielectric resonator according to an example of the present invention will be described below with reference to the drawings. FIG. 1A is an external perspective view of a quarter-wave coaxial dielectric resonator according to an embodiment of the present invention.
FIG. 2B is a longitudinal sectional view of a main part of a quarter-wave coaxial dielectric resonator according to one embodiment of the present invention, and FIG. 2 is a quarter-wave coaxial dielectric according to one embodiment of the present invention. It is a component disassembled perspective view which shows the internal structure of a resonator. Reference numeral 1 is a hollow dielectric, 2 is a hollow part, 4 is an outer conductor, 5 is an inner conductor, 6 is a short-circuit conductor, and 7 is an open end. However, the description is omitted. Reference numeral 8 denotes an outer peripheral electrode formed inside the outer conductor 4 near the open end 7 and electrically connected to the outer conductor 4, and 9 denotes an outer electrode formed near the open end 7 of the inner conductor 5 and electrically connected to the inner conductor 5. The inner electrode on the inner peripheral side, which serves as the capacitor portion A, which opposes the outer electrode 8 on the outer peripheral side with the hollow dielectric 1 interposed therebetween, is a resonator portion similar to the conventional example.

Here, the capacitance section A has a counter electrode structure as shown in FIG. 2, and a large capacitance can be obtained.

The operation of the coaxial dielectric resonator according to the embodiment of the present invention constructed as above will be described below. FIG. 3 is an equivalent circuit diagram of a quarter-wave coaxial dielectric resonator according to an embodiment of the present invention. DR is an equivalent circuit of the resonator section of the coaxial dielectric resonator in one embodiment of the present invention, and C is an equivalent circuit of the capacitance section of the coaxial dielectric resonator in one embodiment of the present invention.

When the characteristic impedance is Z ₀ , the capacitance is C, the phase constant is β, and the angular velocity is ω, the resonator length L is expressed as follows.

L = (1 / β) · tan ⁻¹ (1 / (Z ₀ ωC)) As is clear from this equation, the resonator length L can be reduced by increasing the capacitance C, The coaxial dielectric resonator can be miniaturized.

With respect to the coaxial dielectric resonator having the above-mentioned structure according to the embodiment of the present invention, a method of manufacturing the capacitance portion will be described below. First, an electrode is formed on the dielectric green sheet. Next, these are laminated. Next, integral firing is performed to form the capacitive portion A.

(Embodiment 2) A coaxial dielectric resonator according to a second embodiment of the present invention will be described below with reference to the drawings. FIG. 4 (a) is an external perspective view of a half-wavelength coaxial dielectric resonator in the second embodiment of the present invention, and FIG. 4 (b) is a perspective view of the second embodiment of the present invention. Two
It is a longitudinal cross-sectional view of a wavelength coaxial dielectric resonator. 1 is a hollow dielectric, 2 is a hollow part, 4 is an outer conductor, 5 is an inner conductor,
Reference numeral 7 is an open end, 8 is an outer peripheral side electrode, 9 is an inner peripheral side electrode, A is a capacitor portion, B is a resonator portion, and the above is the same as the configuration of the first embodiment. The difference from the configuration of the first embodiment is that both ends of the hollow dielectric body 1 have open ends 7 and a capacitance portion A is formed.

The operation of the coaxial dielectric resonator according to the second embodiment of the present invention constructed as above will be described below. FIG. 5 shows a first embodiment of the present invention.
FIG. 3 is an equivalent circuit diagram of a coaxial dielectric resonator for 1/2 wavelength. D
Reference symbol R is an equivalent circuit of the resonator portion, which is the same as that of the first embodiment and is given the same reference numeral and its description is omitted. C1 is a first capacitance unit equivalent circuit formed at one end of the coaxial dielectric resonator according to the second embodiment of the present invention, and C2 is another coaxial dielectric resonator according to the second embodiment of the present invention. It is a second capacitance unit equivalent circuit formed at the end.

When the characteristic impedance is Z ₀ , the sum of the capacitances of the two capacitive parts A is C ′, the phase constant is β, and the angular velocity is ω, the resonator length L is expressed as follows.

L = (1 / β) · (π / 2 + tan ⁻¹ (1 / (Z ₀ ωC ′)) As is clear from this equation, the resonator length L can be increased by increasing the capacitance sum C ′. Can be made smaller, and the coaxial dielectric resonator can be made smaller.

The capacitive section A of the coaxial dielectric resonator in the second embodiment of the present invention having the above-described structure can be formed in the same manner as in the first embodiment.

In this embodiment, the hollow dielectric 1
Although the capacitance portion A is formed in the vicinity of both ends of the above, it may be formed at either one end. In addition, the hollow dielectric 1
Although the outer shape of the above is a quadrangular prism and the shape of the hollow portion 2 is a cylindrical shape, these shapes may be any as long as they have a TEM resonance mode.

[0027]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, at least one pair of outer peripheral electrodes, which are electrically connected to the outer peripheral conductor, are provided in the vicinity of at least one open end of the hollow dielectric member, and the outer peripheral electrode and the hollow electrode. By disposing the inner peripheral side electrode that is electrically connected to the inner peripheral conductor and facing each other via the dielectric, the outer peripheral side electrode and the inner peripheral side electrode form a capacity, and thus the capacity is increased. As a result, the resonator length can be reduced without changing the diameter of the hollow portion, the coaxial dielectric resonator can be downsized, and this capacitance is integrally formed in the hollow dielectric body. Since the capacitor is a capacitor, the coaxial dielectric resonator can be further downsized, and since it is not necessary to change the diameter of the hollow portion for downsizing, manufacturing can be facilitated and the mechanical Small that can improve dynamic strength In mass production of low loss, durability, in which the excellent coaxial dielectric resonator reliability can be realized.

[Brief description of drawings]

FIG. 1A is an external perspective view of a quarter-wave coaxial dielectric resonator according to an embodiment of the present invention. FIG. 1B is a quarter-wave coaxial resonator according to an embodiment of the present invention. Longitudinal sectional view of main part of dielectric resonator

FIG. 2 is an exploded perspective view of constituent elements showing an internal structure of a coaxial dielectric resonator for quarter wavelength according to an embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram of a coaxial dielectric resonator for quarter wavelength according to an embodiment of the present invention.

FIG. 4A is a half of the second embodiment of the present invention.
FIG. 3B is a vertical cross-sectional view of the coaxial dielectric resonator for half wavelength according to the second embodiment of the present invention.

FIG. 5 is an equivalent circuit diagram of a half-wavelength coaxial dielectric resonator according to a second embodiment of the present invention.

6A is a plan view of a conventional coaxial dielectric resonator, and FIG. 6B is a vertical cross-sectional view of the conventional coaxial dielectric resonator.

[Explanation of symbols]

 1 Hollow Dielectric 2 Hollow Part 3 Stepped Part 4 Outer Conductor 5 Inner Conductor 6 Short-Circuit Conductor 7 Open End 8 Outer Side Electrode 9 Inner Side Electrode A Capacitance Part B Resonator Part DR Resonator Part Equivalent Circuit C Capacitance Part Equivalent circuit C1 First capacitance unit equivalent circuit C2 Second capacitance unit equivalent circuit

Claims (2)

[Claims] 1. A hollow dielectric, an outer peripheral conductor formed on the outer periphery of the hollow dielectric, an inner peripheral conductor formed in a hollow portion of the hollow dielectric, and a piece of the hollow dielectric. A quarter-wave coaxial dielectric resonator including a short-circuit conductor for electrically connecting the outer conductor and the inner conductor formed on an end surface, wherein the short-circuit conductor of the outer conductor is formed. At least one outer peripheral electrode formed inside the vicinity of the open end, and facing the outer peripheral electrode formed outside the open end of the inner peripheral conductor via the hollow dielectric. A coaxial dielectric resonator comprising: at least one inner circumference side electrode serving as a capacitance section. 2. A half-wavelength band having a hollow dielectric, an outer peripheral conductor formed on the outer periphery of the hollow dielectric, and an inner peripheral conductor formed in the hollow portion of the hollow dielectric. A coaxial dielectric resonator, wherein at least one outer peripheral electrode is formed inside at least one end of the outer peripheral conductor, and the outer periphery is formed outside at least one end of the inner conductor. A coaxial dielectric resonator comprising: a side electrode and at least one inner peripheral side electrode that faces the side surface of the hollow dielectric and serves as a capacitance section.