JP3042163B2 - Coaxial dielectric resonator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial dielectric resonator used in a high frequency band.

[0002]

2. Description of the Related Art In recent years, coaxial dielectric resonators have been widely used in electronic equipment such as various communication equipment and measurement equipment. JP-A-59-144203 discloses this coaxial dielectric resonator.

Hereinafter, a conventional coaxial dielectric resonator will be described. FIG. 7 is a perspective view showing a conventional coaxial dielectric resonator with a terminal removed, and FIG. 8 is a sectional view of a main part of the coaxial dielectric resonator with a terminal inserted.

[0004] 21 is a dielectric formed in a hollow shape, 22 is an internal conductor covering the inner peripheral surface of the dielectric 21, 23 is formed substantially coaxially with the internal conductor 22 covering the outer peripheral surface of the dielectric 21. 24, a short-circuit conductor that covers one end face of the dielectric 21 and connects the internal conductor 22 and the external conductor 23; 25, an inner peripheral hole of the internal conductor 22; A terminal which is inserted into the inner peripheral hole 25 of the inner conductor 22 on the open end face and is electrically connected to the inner conductor 22 by soldering or the like, 27 is a terminal for external connection, 28 is an internal conductor 2 and a conductive adhesive, An inner conductor connecting portion 29 fixed by solder or the like and electrically connected thereto is a stopper formed to have a diameter larger than the inner peripheral hole of the inner conductor 2 and for preventing the terminal from being excessively inserted when the terminal is inserted into the inner conductor 2. is there.

The operation of the conventional coaxial dielectric resonator configured as described above will be described below.

The terminal 26 has a diameter substantially equal to the diameter of the inner peripheral hole 25 of the internal conductor 22, and the length of the internal conductor connecting portion 28 is sufficiently shorter than the length of the dielectric 21. Since the stopper 29 is larger than the inner peripheral hole 25 of the internal conductor 22, the length of the dielectric body changes with the change of the resonance frequency and the length of the insertion and fixing can be easily and easily adjusted in the case of a bandpass filter. .

[0007]

However, in the above-mentioned conventional structure, the internal conductor connecting portion is arranged so as to achieve good electrical continuity with the internal conductor and the terminal is located substantially at the center of the coaxial dielectric resonator. The diameter of the inner conductor connection is almost the same as the diameter of the inner peripheral hole of the inner conductor, and the stopper covers the open end surface of the dielectric. There has been a problem that the connection work with the internal conductor is very troublesome and lacks in workability, thereby lowering productivity. In addition, since the contact area between the internal conductor connecting portion and the internal conductor is large, the terminal thermally expands, causing crazes and cracks in the dielectric, resulting in poor durability.
In addition, such a coaxial dielectric resonator has a problem that the resonance frequency changes after a heat cycle having a large temperature difference, resulting in a lack of reliability.

The present invention solves the above-mentioned conventional problems, and is excellent in workability and productivity such as cleaning and soldering, and
Easy to connect even when multiple dielectric resonators are installed.High quality, low durability with no cracks or crazes in the dielectric even under severe heat cycles and no deterioration of resonance frequency. An object of the present invention is to provide a coaxial dielectric resonator suitable for mass production at low cost.

[0009]

In order to achieve this object, a coaxial dielectric resonator according to claim 1 of the present invention has a hollow coaxial dielectric resonator.
The inner conductor on the inner surface of the dielectric and the outer conductor on the outer surface
A short-circuit conductor that short-circuits the outer conductor and the inner conductor
The chassis is inserted into the inner peripheral hole of the inner conductor and the other parts
Multiple terminals with wider bulges,
1st opposing part extended to the terminal and facing the short-circuit conductor
And a second extending to the first facing portion and facing the external conductor.
An opposing portion, extending on the second opposing portion and on the opposite side of the short-circuit conductor
A third facing portion facing the provided open end face,
The bulging portion and the internal conductor were fixed.

[0010]

According to a second aspect of the present invention, there is provided a coaxial dielectric resonator according to the first aspect, wherein a gap is provided between the open end face and the third facing portion, a substrate is disposed in the gap, and the substrate and the terminal are joined.

[0012]

According to the first aspect of the present invention, the inner conductor and the tar
Since there is a gap between the minals, there is a heat dissipation effect,
And the resonator can be covered by the chassis
Thus, a shielding effect can be provided. According to the second aspect of the present invention, the shield effect including the substrate can be realized and the size can be reduced.

[0013]

[0014]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1A is a perspective view of a coaxial dielectric resonator according to a first embodiment of the present invention, FIG. 1B is a bottom perspective view thereof, and FIG. FIG.

Reference numeral 1 denotes a dielectric body having a square outer periphery and a circular inner periphery. The outer periphery may be a circle or an ellipse other than a polygon such as a quadrangle, and the inner periphery may be an ellipse or a polygon other than a circle, or may further have a step portion. This is because the coaxial dielectric resonator is properly used depending on the size and application.

Reference numeral 2 denotes an internal conductor in which the cross section of the dielectric 1 is coated on the inner peripheral surface of a circular, elliptical or polygonal shape, and the internal conductor 2 has one or more steps inside depending on the size of the dielectric resonator and the application. The section may be formed, and the cross-sectional shape of the inner peripheral surface may be changed between the upper and lower surfaces of the step portion. Reference numeral 3 denotes an outer conductor that covers the outer peripheral surface of the dielectric 1 and has a polygonal, circular, or elliptical cross section, and 4 denotes a short-circuit conductor that covers one end surface of the dielectric 1 and connects the inner conductor 2 and the outer conductor 3. 5 is an inner peripheral hole of the inner conductor 2;
Is a rod-shaped or plate-shaped terminal made of a conductive metal such as brass having a diameter smaller than the inner diameter of the inner conductor 2, 7 is a terminal for external connection of the terminal 6, and 8 is a terminal of the terminal 6 which is folded. This is a terminal connection portion formed by bending or separately attaching a conductive metal to one end surface of the terminal 6.

The operation of the coaxial dielectric resonator of the first embodiment configured as described above will be described below.

The terminal 6 is inserted into the inner peripheral hole 5 of the inner conductor 2 from the short-circuit conductor 4 side substantially at the center of the inner peripheral hole 5, and then the terminal connection portion 8 and the short-circuit conductor 4 are connected to the terminal 6 by soldering or a conductive adhesive. And the dielectric 1 are fixed.

Next, the influence of the heat cycle on the coaxial dielectric resonator of this embodiment will be described below.

As samples, five samples each of the first embodiment and five conventional products shown in FIG. 7 were prepared as comparative examples.

The test method is such that each coaxial dielectric resonator is set to -4
It was left in an environment of 0 ° C. for 30 minutes, then the temperature was raised to + 85 ° C., and left for 30 minutes to form one cycle. This was repeated, and the change in resonance frequency was measured. The results are shown in FIGS. 3 (a) and 3 (b). FIG. 3A is a diagram showing the heat cycle dependence of the resonance frequency of the coaxial dielectric resonator of the first embodiment. FIG. 3B is a graph showing the resonance frequency of the conventional coaxial dielectric resonator. It is a figure which shows heat cycle dependence. In the figure, the horizontal axis represents the number of heat cycles, and the vertical axis Δf represents a change in the resonance frequency.

As apparent from FIG. 3A, the resonance frequency of the sample of the first embodiment changes only by about ± 0.1 MHz even in the sample having the largest frequency change. On the other hand, as is clear from FIG. 3B, the conventional product has +4 in the sample having the largest frequency change.
The resonance frequency changed near MHz, and a change in the resonance frequency of +2.6 MHz was observed even in the sample with the smallest change in frequency.

As a result, it can be said that the coaxial dielectric resonator of this embodiment is more than several tens of times more stable in resonance frequency than the conventional product and more durable than the conventional product. Next, the dependence of the external quality factor (Q) on the capacitance (C) of the coaxial dielectric resonator of the present embodiment will be described below.

As samples, ten samples each of the present example and a comparative example shown in FIG. 7 were prepared.

As test devices, electric circuits for characteristic evaluation shown in FIG. 4 were prepared. FIG. 4A is a schematic diagram of an electric circuit for evaluating the characteristics of the coaxial dielectric resonator according to the present embodiment.
(B) is a schematic diagram of an electric circuit for evaluating characteristics of a conventional coaxial dielectric resonator.

The test was performed by mounting each coaxial dielectric resonator on each characteristic evaluation electric circuit. The results are shown in FIG.

FIG. 5A is a diagram showing the capacitance dependence of the external Q value of the coaxial dielectric resonator according to the present embodiment, and FIG.
FIG. 4 is a diagram showing the capacity dependence of the external Q value of a conventional product. FIG.
As is clear from FIGS. 5A and 5B, the coaxial dielectric resonator of this embodiment has almost the same connectivity with electrodes as the conventional product despite its extremely simple structure. It can be said that.

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 6A is a perspective view of a coaxial dielectric resonator according to a second embodiment of the present invention, and FIG. 6B is a perspective view of FIG.
FIG. 6C is a sectional view of a main portion taken along line AA of FIG.
It is a principal part sectional view of the BB line of (a).

1 is a dielectric, 3 is an external conductor, 4 is a short-circuit conductor, 5 is an inner peripheral hole, 7 is a terminal for external connection of a terminal,
Reference numeral 8 denotes a terminal connection part, which is the same as that of the first embodiment, and the same reference numeral is used, and the description is omitted. 2 '
Is an internal conductor having a large-diameter inner peripheral hole and a small-diameter inner peripheral hole separated by the step portion 12, 61 is a terminal made of a conductive metal having a large elastic modulus, for example, phosphor bronze or beryllium copper, and 9 is the inside of the terminal 61. A bulging portion formed at a predetermined portion of the insertion portion of the conductor 2 ′ and in contact with the inner periphery of the internal conductor 2 ′ is an insulating substrate on which an electrode pattern is formed, and a terminal 7 for external connection is an electrode pattern Is connected to Reference numeral 11 denotes a metal chassis on which an insulating substrate 10 is disposed and a plurality of terminals 61 are extended on one side edge thereof. Bulge 9
Is made of a highly elastic metal plate and can be easily bent even when expanded by heat, so that the dielectric 1 is not deformed.
The bulging portion 9 may be formed with a hollow portion such as a circle or an ellipse. Forming the hollow portion facilitates elastic deformation, so that it can be used irrespective of the size of the inner peripheral hole of the internal conductor 2 ′, so that the number of parts can be reduced and the terminal 61 is thermally expanded. The stress can also be reduced by the hollow portion.

With this configuration, according to the present embodiment, the dielectric 1 can be firmly fixed by the bulging portion 9 even if the coaxial dielectric is incorporated in the chassis without any gap. Further, even if the terminal 61 thermally expands, the stress is absorbed by the bending of the bulging portion 9, so that no craze or crack is generated in the dielectric 1. Further, the short-circuit conductor 4 connects the terminal 61
Can be soldered very easily and cleaning can be performed very easily.

[0033]

The coaxial dielectric resonator according to claim 1 of the present invention.
Indicates the inner conductor on the inner peripheral surface of the hollow dielectric and the outer conductor on the outer peripheral surface.
Short the outer conductor and the inner conductor on one end face
Provide a short-circuit conductor and insert the chassis into the inner peripheral hole of the inner conductor.
Multiple bulges with wider bulges than other parts
And a terminal extending to the terminal and facing the short-circuit conductor.
A first opposing portion and an outer conductor extending from the first opposing portion and facing the outer conductor
A second opposing portion, and a short-circuit conductor extending from the second opposing portion.
Opposing portion facing the open end face provided on the side opposite to
That the bulge and the inner conductor are fixed.
Therefore, a gap is provided between the internal conductor and the terminal
So it has a heat radiation effect, is strong against heat cycle,
There is no change in characteristics, and the resonator is
Because it can be covered, it can have a shielding effect
As a result, the noise immunity characteristics are improved. According to a second aspect of the present invention, in the coaxial dielectric resonator according to the first aspect, a gap is provided between the open end surface and the third facing portion, and the substrate is disposed in the gap.
By joining the substrate and the terminal, a shielding effect including the substrate can be realized, and downsizing can be realized by disposing the substrate in a dead space portion.

[Brief description of the drawings]

1A is a perspective view of a coaxial dielectric resonator according to a first embodiment of the present invention, and FIG.

FIG. 2 is a sectional view of a main part of the coaxial dielectric resonator according to the first embodiment of the present invention.

FIG. 3 (a) is a diagram showing the heat cycle dependence of the resonance frequency of the coaxial dielectric resonator of the first embodiment. (B) The heat cycle dependence of the resonance frequency of the conventional coaxial dielectric resonator. Diagram shown

FIG. 4A is a schematic diagram of an electric circuit for evaluating characteristics of a coaxial dielectric resonator of the first embodiment; FIG. 4B is a schematic diagram of an electric circuit for evaluating characteristics of a conventional coaxial dielectric resonator;

5A is a diagram showing the capacitance dependence of the external Q value of the coaxial dielectric resonator of the first embodiment. FIG. 5B is a diagram showing the capacitance dependence of the external Q value of a conventional product.

6A is a perspective view of a coaxial dielectric resonator according to a second embodiment. FIG. 6B is a cross-sectional view of a main part taken along line AA in FIG. 6A. Cross section of main part of line B

FIG. 7 is a perspective view showing a state where a terminal of a conventional coaxial dielectric resonator is removed.

FIG. 8 is a cross-sectional view of a main part of a conventional coaxial dielectric resonator with terminals inserted therein.

[Explanation of symbols]

 1, 21 Dielectric 2, 2 ', 22 Inner conductor 3, 23 Outer conductor 4, 24 Short-circuit conductor 5, 25 Inner peripheral hole 6, 61, 26 Terminal 7, 27 Terminal for external connection 8 Terminal connection portion 9 Swelling Part 10 Insulating substrate 11 Chassis 12 Step part 13, 14 Measurement port 28 Internal conductor connection part 29 Stopper

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Eiichi Ochiai 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-company (72) Inventor Hiromitsu Taki 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-62-15901 (JP, A) JP-A-59-201502 (JP, A) JP-A 2-53603 (JP, U) JP-A 63-144706 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01P 7/04 H01P 1/205 H01P 5 / 08

Claims (2)

(57) [Claims] 1. A hollow dielectric, an outer conductor covering an outer peripheral surface of the dielectric, a short-circuit conductor connected to the outer conductor and covering one end surface of the dielectric, and a short-circuit conductor connected to the short-circuit conductor. An inner conductor for covering an inner peripheral surface of the dielectric, and a chassis, wherein the chassis is inserted into the inner peripheral hole of the inner conductor with a gap therebetween and is wider than other portions.
A plurality of terminals, a first facing portion extending to the terminal and facing the short-circuit conductor, a second facing portion extending to the first facing portion and facing the external conductor, A third opposing portion extending to the second opposing portion and opposing an open end face provided on the opposite side to the short-circuit conductor, and fixing the bulging portion and the inner conductor. Characteristic coaxial dielectric resonator. Wherein a gap is provided between the open end face and the third face portion, the substrate is disposed in the gap, coaxial dielectric resonator according to claim 1, wherein the bonding the substrate and the terminal.