JPS6311761Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a filter, for example, a stripline filter using a dielectric resonant element.

Conventionally, as a filter used in the VHF band,
There are those that use LC resonance and those that use helical resonance. Q is a filter that uses LC resonance.
However, filters using helical resonance have the drawback of being large in size. Therefore, recently, stripline filters in which a plurality of resonant electrodes are formed on the surface of a dielectric substrate are often used. This stripline filter is formed by printing silver or the like on the surface of a dielectric substrate and then baking it. However, in such a strip line filter, it is not possible to arbitrarily increase or decrease the number of resonant electrodes or change the degree of coupling after manufacturing. Furthermore, a coaxial TEM resonator has been developed in which an inner guide shaft and an electrode film serving as an outer conductor are formed on the inner and outer peripheral surfaces of a cylindrical ceramic dielectric, but as the frequency decreases, the axial length of the cylindrical dielectric decreases. Due to manufacturing technology, it is difficult to form a long and uniform cylindrical ceramic dielectric.

Therefore, the main purpose of this invention is to provide a filter with a relatively simple structure in which the number of resonant electrodes can be increased or decreased as desired, and the degree of coupling can be freely adjusted.

To summarize this invention, at least one dielectric resonator including an electrode film formed on at least the opposing main surface of a dielectric element excluding at least the opposing side surfaces is prepared, and the dielectric resonator is The resonator is mechanically fixed to the mounting surface of the case, and the case is equipped with an input coupler for giving an input signal to the dielectric resonator and an output coupler for extracting the output signal from the dielectric resonator. It is something.

The above objects and other objects and features of the present invention will become more apparent from the detailed description given below with reference to the drawings.

FIG. 1 is an external perspective view showing an example of a dielectric resonant element included in an embodiment of this invention. In the figure, first, a dielectric material 11 having a rectangular cross-sectional shape and a rod shape is prepared. This dielectric 11 is made of ceramic or the like having a dielectric constant ε of about 90. Electrode films 12 and 1 are formed on the main surface of the dielectric 11 excluding the side surfaces facing each other in the longitudinal direction and the end surface of one side.
3 and 14 are formed. That is, in FIG. 1, an electrode film 12 made of, for example, silver or copper is formed on the upper main surface, and an electrode film 13 is similarly formed on the lower main surface. In order to make this dielectric resonant element 1 a 1/4 wavelength resonant element, a short-circuiting electrode film 14 is formed on one end face to short-circuit the electrode films 12 and 13. Note that when this dielectric resonant element 1 is used as a 1/2 wavelength resonant element, the short-circuit electrode film 14 is not formed.

2 is a plan view showing an example of a stripline filter using the dielectric resonant element shown in FIG. 1, and FIG. 3 is a plan view showing the stripline filter shown in FIG. 2 cut along the line -. It is an external perspective view.

In the figure, the case 2a is made of a metal material and is formed in a box shape with an open top. Two partition walls 21 and 22 are formed inside the case 2a to divide the inside in the longitudinal direction.
The partition walls 21 and 22 form storage sections 25 to 27 for storing the three resonator elements 1a to 1c. Also, notches 23 and 24 for storing chip capacitors 42 and 43, which will be described later, are formed on one side of the partition walls 21 and 22.
Spacers 3a to 3c made of an insulating material such as plastic or ceramic with a low dielectric constant and formed in substantially the same shape as the dielectric resonator elements 1a to 1c are disposed on the spaces 5 to 27. The dielectric resonator elements 1a to 1c are then fixed onto the spacers 3a to 3c by adhesive or the like.

In addition, external connection terminals 61 formed of coaxial connectors, for example, are provided through both side surfaces of the case 2a.
62 is provided. A chip capacitor 41 for coupling as an input side coupler is connected between the center conductor of the external connection terminal 61 and the electrode film 12a of the dielectric resonant element 1a. Further, a chip capacitor 42 as an interstage coupler is connected between the electrode film 12a of the dielectric resonant element 1a and the electrode film 12b of the dielectric resonant element 1b, and this chip capacitor 42 is formed on the partition wall 21. It is stored in the cutout portion 23. Similarly, the electrode film 12b of the dielectric resonant element 1b and the electrode film 12 of the dielectric resonant element 1c
A chip capacitor 43 is connected between
This chip capacitor 43 is housed in the cutout portion 24 of the partition wall 22. Furthermore, dielectric resonant element 1
A chip capacitor 44 as an output side coupler is connected between C and the center conductor of the external connection terminal 62.

A cover 2b is provided on the upper surface of the case 2a. The cover 2b is made of the same metal material as the case 2a, and is formed by bending both sides to cover the case 2a. A plurality of through holes 28 are formed on the upper surface of the cover 2b at corresponding portions of the partition walls 21 and 22 of the case 2a. Solder is poured into the through holes 28, and the cover 2b is fixed to the upper surface of the partition walls 21, 22.

By configuring a strip line filter in this way and inputting, for example, a VHF signal between the external connection terminal 61 and the case 2a, a VHF signal within a predetermined frequency range can be transmitted between the external connection terminal 62 and the case 2a. I get a signal.

Since the individually formed dielectric resonant elements 1a to 1c are arranged in the case 2a in this way, the number of dielectric resonant elements 1 can be increased or decreased as desired. Furthermore, when changing the frequency, it is sufficient to use a dielectric resonant element having a length corresponding to the frequency, and when it is desired to increase the degree of coupling between each dielectric resonant element 1a to 1c, electrostatic It is only necessary to increase the capacity, and the degree of freedom as a strip line filter can be increased. Furthermore, if it is desired to increase the Q of each dielectric resonant element, the cross-sectional area of the dielectric may be increased.

FIG. 4 is a plan view showing another example of the stripline filter. This FIG. 4 is the same as FIG. 2 except for the following points. That is, the partition wall 21,
22, that is, the dielectric resonant elements 1a to 1c
A portion 31 having a predetermined length from near the short-circuited end of
Notches 29 and 30 are formed so that 32 remains. Then, U-shaped magnetic coupling lines 71 and 72 are provided so as to surround the portions 31 and 32 having a predetermined length of the partition walls 21 and 22. The tip of each magnetic coupling wire is
It is connected to case 2a. Further, the external connection terminal 61 and the dielectric resonant element 1a are electromagnetically coupled by the magnetic coupling line 73, and the external connection terminal 62 and the dielectric resonance element 1c are coupled by the magnetic coupling line 74. That is, in the above-mentioned FIG. 2, each of the dielectric elements 1a to 1c and the external connection terminal are electrostatically coupled, but in this FIG. 4, they are configured to be electromagnetically coupled.

As described above, according to this invention, at least one dielectric resonator including an electrode film formed on at least the opposing main surface of the dielectric element, excluding at least the opposing side surfaces, is connected via an insulating spacer. Since the filter is configured by mechanically fixing it to the mounting surface of the case and providing an input side coupler and an output side coupler in the case, the number of dielectric resonators can be increased or decreased as desired, and the degree of coupling can be adjusted. can be adjusted freely. Further, since the frequency can be easily changed by changing the length of the dielectric resonator, the degree of freedom as a filter can be increased.

[Brief explanation of drawings]

FIG. 1 is an external perspective view showing an example of a dielectric resonator included in an embodiment of this invention. FIG. 2 is a plan view showing an example of a stripline filter using the resonant element shown in FIG. 1. FIG. 3 is an external perspective view of the strip line filter shown in FIG. 2, cut along line -. FIG. 4 is a plan view showing another example of the strip line filter. In the figure, 1 is a dielectric resonant element, 11 is a dielectric, 12, 13, 14 are electrode films, 2a is a case,
2b is a cover, 41 to 44 are chip capacitors,
61 and 62 indicate external connection terminals.

Claims (1)

[Claims for Utility Model Registration] (1) At least one dielectric resonator including a dielectric element and an electrode film formed on at least the opposing main surfaces of the dielectric element, excluding at least the opposing side surfaces. , a case for housing the dielectric resonator, and a case provided between the dielectric resonator and the mounting surface of the case for mechanically fixing the dielectric resonator to the mounting surface of the case. an insulating spacer; an input coupler provided in the case for providing an input signal to the at least one dielectric resonator; and an input coupler provided in the case for extracting an output signal from the at least one dielectric resonator. A filter with an output coupler. (2) At least two or more of the dielectric resonators are provided and arranged on the mounting surface of the case, and the input side coupler is a dielectric at one end of the at least two or more dielectric resonators. The output side coupler is coupled to a resonator, and the output side coupler is coupled to a dielectric resonator at the other end of the at least two dielectric resonators, and further includes an interstage coupling between the dielectric resonators. The filter according to claim 1, which includes a coupler. (3) The case is provided with a storage section that individually stores each of the at least two dielectric resonators, and each storage section is configured to couple adjacent dielectric resonators with each other. 2. The filter according to claim 1 or 2, which is partitioned by a partition wall except for the portion where the filter is separated. (4) The filter according to any one of claims 1 to 3, wherein the input coupler and the output coupler are each capacitive couplers. (5) The filter according to claim 4, wherein the capacitive coupler is a chip capacitor. (6) The filter according to any one of claims 1 to 5, wherein the input coupler and the output coupler are electromagnetic couplers.