JPS637683B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in dielectric filters used in mobile radio equipment and the like, and particularly relates to dielectric filters with improved input/output coupling terminals.

Conventional dielectric filters used in mobile radios, especially in-vehicle radios, are provided with holes constituting a plurality of resonators at predetermined intervals in one dielectric block. FIG. 1 shows a conventional dielectric filter in which the entire surface except the top surface and both end surfaces is metallized, and holes for adjusting the degree of coupling are provided between holes adjacent to the resonator holes. In the figure, a is a plan view of the case with the lid removed, and b is a sectional view of the main part from the front. 1 is made of a high dielectric material and has a plurality of resonator holes 11 and holes 12 for adjusting the degree of coupling between resonators. 2 is a conductive film formed on the inner surface of the resonator hole 11; 3 is a conductive film formed on the outer surface of the dielectric block 1 except for the top surface and both end faces; 4 is a dielectric Input/output conductive films are provided on both end faces of the block 1, 5 is a case made of metal or the like and houses the dielectric block 1, 6 is an input/output connector, and 7 is a lid of the case 5. Adjustment screws 8 and coupling adjustment threaded rods 9 corresponding to the resonator holes 11 and coupling degree adjustment holes 12 of the dielectric block 1 are attached, and the adjustment screws 8 and adjustment screw rods 9 are They are each provided with fixing nuts 81 and 91. The conductor films 2, 3, and 4 are formed, for example, by a metallization method in which a viscous material of silver and glass is applied and then heated. Further, the input/output conductor film 4 and the input/output plug 6 are connected respectively.

In this way, the resonance frequency adjustment screw 8 and the coupling degree adjusting threaded rod 9 are respectively rotated to adjust the frequency and coupling degree to a predetermined value, and then the fixing nuts 81 and 91 are tightened and fixed. However, mobile radio devices (vehicle-mounted, portable, etc.) are required to be small and lightweight, but the conventional devices mentioned above are equipped with input/output connectors 6 for connecting external conductors, so the dielectric filter itself is small. There was an unavoidable problem that hindered the development of the system.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems by focusing on input/output coupling terminals based on electrical energy coupling. Briefly stated, the present invention provides a dielectric filter in which holes constituting a plurality of resonators are formed in a dielectric block, in which holes for input/output coupling terminals are formed in the surface of the dielectric block in parallel with the holes for the resonators. By inserting a rod-shaped input/output coupling terminal having a contact piece and a stopper larger than the diameter of the terminal insertion hole into the terminal insertion hole, the tip of the contact piece is rotated inside the hole in the opposite direction to the insertion direction. It is characterized by comprising an input/output coupling terminal which supports the terminal so as to elastically deform and prevent it from being pulled out, and whose insertion position is determined by the stopper being in contact with the surface of the dielectric block. . Embodiments of the dielectric filter according to the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a perspective view for explaining one embodiment of the dielectric block according to the present invention, in which 20 is made of a porcelain plastic material with a high dielectric constant and is molded and sintered, and has a plurality of resonator holes 201. The dielectric block 21 has holes 202 for adjusting the degree of coupling between the resonator and the resonator, and holes 203 for inserting input/output coupling terminals are formed in parallel with the resonator holes at both ends. The conductive film 22 formed on the inner surface of the resonator hole 201 is a conductive film metallized on the outer surface of the dielectric block 20 except for the upper surface and both end surfaces in the longitudinal direction. These conductor films 21 and 22 are coated with a viscous material of silver and glass,
It is formed by a heating metallization method or the like. Note that the holes 202 and 203 are not metalized. With this outer conductor film 22 and dielectric,
The conductive film 21 of the formed hole 201 constitutes a quarter wavelength resonator as an internal conductor, and is coupled between stages.

Figure 3 is for explaining one embodiment of a dielectric filter to which the dielectric block shown in the previous figure is applied, where a is a plan view and b is a cross-sectional view of the main part from the front, showing the same parts as in the previous figure. are marked with the same reference numerals. 2
3 is a case made of metal or the like that houses the dielectric block 20, 24 is a lid of the case 23 with holes 241 for input/output coupling terminals, and 25 is an input/output coupling terminal inserted into the input/output coupling terminal insertion holes 203. The input/output coupling terminal 25 is a terminal insertion hole 20.
The contact piece 251 is made up of a plurality of contact pieces 251 having a diameter larger than that of the hole 3, a stopper 253, and a rod-shaped terminal portion 252 that penetrates through these pieces.

After storing the input/output coupling terminal 25 in the metal case 23 with the contact piece 251 side inserted into the input/output coupling terminal insertion hole 203 of the dielectric block 20 detailed in the previous figure, as shown in FIG. A lid 24 is mounted on the case 23, which is equipped with resonance frequency adjustment screws 8 and coupling degree adjustment threaded rods 9 corresponding to the holes 201 and 202 of the dielectric block 20 shown, and has holes 241 for input/output coupling terminals drilled therein. Place and fix. Then, with an external conductor (not shown) connected to the input/output coupling terminal 25, the resonance frequency adjusting screw 8 and the coupling degree adjusting threaded rod 9 are rotated to adjust the frequency and coupling degree to a predetermined value. Tighten and secure nuts 81 and 91. In this way, since the input/output connectors are not attached to the side of the case, miniaturization can be achieved.

In Fig. 4, a is a front view for explaining the input/output coupling terminal, and b is a front view of the input/output coupling terminal inserted into a dielectric block. The length and thickness of the terminal portion 252, which is a rod-shaped terminal, to be inserted into the dielectric block and the contact piece 251 are determined by the electrical coupling strength of the input/output coupling terminal 25. The relationship between K and the length L of the terminal portion 252 is shown in FIG.

Since the main purpose of the present invention is to improve vibration resistance and workability, point b in FIG. 5 is not used, but point b, that is, a long terminal portion 252 is used. In the terminal portion 252, a contact piece 25 is provided with a cut (not shown) from the periphery toward the center using a thin piece for a stopper.
1 is attached to the input/output coupling terminal insertion hole 203.
When the contact piece 251 is inserted into the hole 20 as shown in FIG.
The terminal portion 252 is supported at the center of the hole 203 in such a manner that it bites into the inner surface of the hole 203, preventing movement in the direction of coming out, and fixing the terminal portion 252 so as to withstand external vibration.

As described above, the insertion position is determined by pushing the input/output coupling terminal into the hole 203 until the stopper 253 comes into contact with the surface of the dielectric block.

Furthermore, according to the present invention, since the input/output coupling terminal is provided in parallel with the resonator hole, it is possible to metalize the longitudinal end face of the dielectric block, which was the conventional input/output coupling surface, and the electromagnetic field energy can be reduced. The confinement effect is improved.

In this embodiment, a 1/4 wavelength dielectric filter has been described, but if a conductive film is also formed on the surface of the dielectric block 20, it can be applied as a 1/2 wavelength dielectric filter. Also, the resonator hole 20
The conductive film applied to the inner surface of the conductor 1 is not limited to the metallization method, and may be a metal ring or the like.

As is clear from the above description, according to the dielectric filter of the present invention, compared to the conventional method in which external conductors are connected via input/output connectors, the case Since it can be made smaller and lighter in weight, it is extremely advantageous to apply it to various mobile radio devices and the like.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a conventional dielectric filter with the lid removed, b is a sectional view of main parts from the front, and Fig. 2 is an example of a dielectric resonator according to the present invention. FIG. 3 is a perspective view for explaining an embodiment of the dielectric filter according to the present invention.
is a plan view, b is a sectional view of main parts from the front, FIG. FIG. 5 is a characteristic line diagram for explaining the relationship between electrical coupling strength and terminal length. In the figure, 1 and 20 are dielectric blocks;
2, 3, 4, 21 and 22 are conductor films, 5 and 23 are cases, 6 is an input/output connector, 7 and 24 are lids, 8 is a screw for adjusting the resonance frequency, 9 is a threaded rod for adjusting the degree of coupling, 11 and 201 is a resonator hole, 12
and 202 is a hole for adjusting the coupling degree, 25 is a terminal for input/output coupling, 241 is a hole for input/output coupling terminal, 251
indicates a contact piece, a terminal portion 252, and a stopper 253.

Claims (1)

[Claims] 1. In a dielectric filter in which holes constituting a plurality of resonators are formed in a dielectric block, holes for input/output coupling terminals are formed in the surface of the dielectric block in parallel with the holes for the resonators, and holes for input/output coupling terminals are formed in the surface of the dielectric block, and By inserting a rod-shaped input/output coupling terminal having a contact piece and a stopper larger than the diameter of the hole into the terminal insertion hole, the tip end of the contact piece is elastically deformed inside the hole in the opposite direction to the insertion direction and is not pulled out. 1. A dielectric filter comprising an input/output coupling terminal that supports the terminal so as to block the input and output, and the stopper is in contact with the surface of the dielectric block to determine the insertion position.