JPH073682Y2 - Dielectric filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention mainly relates to a dielectric filter used in a microwave band. More specifically, by forming a conductor pattern that extends radially from the open end of the resonator hole of the dielectric resonator, a capacitor can be connected to it, and by removing the part protruding from the capacitor in the connected state, the electrical The present invention relates to a dielectric filter whose adjustable characteristics can be adjusted.

This filter is used in fields such as mobile communications such as car telephones and satellite communications.

[Prior Art] As a dielectric filter, for example, as shown in FIG. 5, a plurality of (here, four) resonator holes 12 and coupling holes 14 are alternately arranged in the longitudinal direction of a rectangular parallelepiped dielectric block 10. A λ / 4-type dielectric body in which a conductor film 16 is formed on one of the open surfaces (the upper surface in this case) of the open surfaces and the inner surface of the resonator hole except the open surface. Some use a coaxial resonator.

As one of the input / output couplings of such a dielectric filter,
There is a structure in which coupling capacitors are attached to the open ends of the resonator holes located at both ends. Therefore, a rivet-shaped metal terminal is inserted or a conductor pattern is provided at the open end of the resonator hole. Among them, the conductor pattern method shown in FIGS. 5 and 6 is preferable because no special parts are used. The conventional conductor pattern 18 is merely a ring and is smaller than the capacitor 20 placed on it. That is, when the capacitor 20 is mounted and connected, the conductor pattern 18 is hidden.

[Problems to be Solved by the Invention] When it is necessary to adjust the electrical characteristics of a conventional dielectric filter, for example, the resonance wave number, the end surface or edge portion of the dielectric block is shaved off. Therefore, it is necessary to leave a space between the case and the dielectric block to some extent so that the work can be performed, and there is a drawback that the case becomes larger than necessary. In addition, there is a risk that the wiring or the like may be damaged when the shaving is adjusted. For this reason, the work is complicated and requires skill.

The object of the present invention is to eliminate the drawbacks of the prior art as described above, eliminate the work of adjusting the scraping of the end surface or the edge portion of the dielectric block, and make it possible to bring the case and the dielectric block into close contact with each other. Another object of the present invention is to provide a dielectric filter that can be made stable and can be adjusted more accurately and stably.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a conductor pattern for connecting a capacitor has a plurality of tongue-shaped portions extending radially from the periphery of the open end of the resonator hole, and a plurality of tongue-shaped portions are provided. All of the ends are connected to the conductor film of the resonator hole, and the ends are configured to protrude from the capacitor when the capacitor is mounted and connected.

[Operation] Since the conductor pattern for connecting the capacitor extends radially and protrudes from the capacitor with the capacitor connected,
It is possible to scrape off the tip of the conductor pattern. When the conductor pattern is shaved from the tip side, the area of the conductor pattern changes, so that the capacitance of the capacitor is apparently changed. That is, the resonance frequency changes in the downward direction. Since scraping can be performed for each tongue-shaped portion, excessive scraping is eliminated.
Also, if you can grasp the part to be cut depending on the model, you can cut the same place, which leads to a reduction in adjustment time.

[Embodiment] FIG. 1 is an exploded perspective view showing an embodiment of the present invention. The basic structure of the dielectric resonator may be the same as that of the prior art except for the conductor pattern shape at both ends thereof. A substantially rectangular parallelepiped dielectric block 10 made of a sintered body of a high dielectric constant material for microwaves is used. This dielectric block 10 has a stepped structure in which the central portion is high and both end portions are low. Four resonator holes 12 are formed at intervals in the longitudinal direction of the dielectric block 10, and a coupling hole 14 is provided between them. Conductors are formed on the outer surface of the dielectric block except the open surface and on the inner wall surface of the resonator hole 12 with one of the surfaces where the resonator hole 12 is open as the open surface (upper surface in FIG. 1) and the other as the short-circuit surface. The film 16 is formed. In the figure, the shaded portions represent the surface on which the conductor film is provided, and the portions with fine dots represent the surface without the conductor film and the dielectric substrate exposed. The conductor film 18 may be a layer of an extremely thin conductive material formed by baking silver paste or the like.

In such a dielectric resonator, a conductor pattern (22) for connecting a capacitor, which conducts to the conductor film on the inner wall surface of the resonator hole (12) located at both ends, is provided on the open surface, and the capacitor (20) is provided on the conductor pattern (22). Connected with. The feature of the present invention is the shape of the conductor pattern 22. Here, four tongue-shaped portions 22a extend radially from the ring-shaped portion 22b around the open end of the resonator hole, all of their base ends are connected to the conductor film of the resonator hole 12, and all the tips are connected to the capacitor 20. It is designed to stick out.

The capacitor 20 is mainly located on the ring-shaped portion 22b,
It is connected by soldering, or it is mounted by applying a conductor pattern and then fixed by fixing at the same time as baking.

As shown in FIG. 2, the tip of each tongue-shaped portion 22a of the conductor pattern 22 is projected from the capacitor 20 shown by the phantom line, and is connected in that state as shown in FIG. Therefore, the protruding tongue-shaped portion 22a can be easily scraped off, whereby electrical adjustment can be performed.

The shape of the conductor pattern can be variously changed. An example thereof is shown in FIG. FIG. A is an example in which the conductor pattern 24 is formed in a cross shape, and FIG. B is an example in which more tongue-shaped portions 26 are radially provided. In these, the tips of all the tongue-shaped portions are projected beyond the capacitor 20. In FIG. 6C, long tongue-shaped portions 22a and short tongue-shaped portions 28b are alternately provided, and only the longer one has a capacitor 2 at the tip.
This is an example where it is set to extend from 0. The shape of the conductor pattern is not limited to these. However, when scraping, the scraping is carried out sequentially from the tip so that a separated conductor pattern is not formed. This is because the presence of the separated conductor pattern causes a large amount of inconvenience, for example, extra stray capacitance appears and the operation becomes unstable.

The above embodiment is an example of a bandpass filter having four resonator holes and coupling holes between them, but the number of resonator holes formed (the number of stages) is not limited to four, and any number is possible. It can be applied to the filter of the number of stages. It can also be applied to filters that do not have holes for coupling. It can be applied to a dielectric resonator having a single resonator hole, and may be used not only as an input / output structure but also for rejection. In any case, the present invention is
It can be used in all cases where a capacitor needs to be connected to the resonator hole of a dielectric resonator.

[Effect of the Invention] As described above, according to the present invention, as a conductor pattern for connecting a capacitor, a plurality of tongue-shaped portions radially extend from the periphery of the open end of the resonator hole, and the base ends thereof are all conductors of the resonator hole. Since it is connected to the film and the tip is shaped to protrude from the mounted capacitor, not only can the capacitor be mounted and connected, but the electrical characteristics of the dielectric resonator can also be obtained by scraping off the protruding conductor pattern. The effect that the adjustment can be easily performed occurs.

In the present invention, since the conductor pattern on the open surface side is shaved off, it is not necessary to provide an extra space between the case and the dielectric resonator, and the case can be miniaturized. Further, since the shaving operation is performed for each tongue-shaped portion, defects due to excessive shaving do not occur, and if the shaving portion can be grasped by the model, it suffices to shave the same place, so that the adjustment time can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing an embodiment of a dielectric filter according to the present invention, FIG. 2 is a partial plan view of an end portion of the dielectric block, and FIG. 3 is an assembled view. 4A, 4B, 4C are explanatory views showing an example of a conductor pattern for connecting a capacitor, FIG. 5 is an exploded perspective view showing an example of a conventional technique, and FIG. 6 is a dielectric block thereof. It is a partial top view. 10 ... Dielectric block, 12 ... Resonator hole, 14 ... Coupling hole, 16 ... Conductor film, 18,22 ... Conductor pattern, 20 ... Capacitor, 22a ... Tongue-shaped part.

Claims (1)

[Scope of utility model registration request] 1. A quarter-wave type dielectric coaxial resonator is provided with a conductor pattern for connecting a capacitor, which is electrically connected to a conductor film on an inner wall surface of a resonator hole, on the open surface, and the capacitor is mounted on the conductor pattern. In the connected dielectric filter, the conductor pattern has a plurality of tongue-shaped portions radially extending from the periphery of the resonator hole open end, all the base ends of which are connected to the conductor film of the resonator hole, and the tip end thereof is A dielectric filter with a shape protruding from the capacitor.