JPH03158001A - Dielectric filter - Google Patents

Abstract

PURPOSE:To form a dielectric filter with a small height and a high attenuation characteristic by connecting an SIR dielectric coaxial resonator to the substrate of a coupling capacitor while being penetrated through a hole of a sub transmission line base. CONSTITUTION:SIR dielectric coaxial resonators 6a-6d are penetrated through each hole 8b of a sub-transmission line base 8 and a central metallic fixture 9 made of a metal to connected to the substrate of a coupling capacitor 7 is inserted to the inner conductor of the SIR dielectric coaxial resonators 6a-6d and the hole 7d of the coupling capacitor base 7, respectively, and soldered by using solder 12. An input output terminal 10 made of a metal is inserted to a hole 7d of the substrate 7 and soldered by solder 12. Then a connection metallic fixture 11 made of a metal to connect the substrate 7 and the base 8 is inserted to the hole 7a of the substrate 7 and the hole 8a of the base 8 respectively and soldered by the solder 12. Thus, a dielectric filter with a small height and a high attenuation characteristic is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a dielectric filter that is compact and can realize high attenuation characteristics.

(Conventional technology) A conventional dielectric filter will be explained with reference to FIG.

The dielectric coaxial resonators 1a, lb, le, and ld are made of dielectric rectangular tubes, and electrodes are formed by silver metallization or the like on one end surface other than the open end surface, the outer peripheral surface, and the entire inner surface. A center metal fitting 2 made of metal is inserted into the inner periphery of the dielectric coaxial resonators 1a, lb, lc, and ld and attached by soldering or the like. The coupling capacitor board 3 is shown in Figure 6 (
As shown in A) to (C), a dielectric coaxial resonator 1a made of a dielectric substrate with excellent high frequency characteristics such as alumina,
LB, LE, LD center fittings 2 and input/output terminals 5
Holes 3b and 3a for connection with are provided. The coupling capacitance with the input/output terminal 5 is formed between the front and back electrodes 3e and 3f of the coupling capacitor board 3.

In addition, dielectric coaxial resonators 1a, lb, le, ld
The coupling capacitance between the electrodes 3e is on the same surface of the coupling capacitor substrate 3.

3d and 3e are formed. As shown in FIGS. 5(A) to 5(C), the sub-transmission line board 4 is made of a dielectric board with excellent high frequency characteristics, and includes dielectric coaxial resonators 1a, lb, le.
.

Holes 4a and 4b for connection and penetration with center metal fitting 2 of 1d
is provided. On the surface of the substrate, electrodes 4C*t4e for forming input electrodes and output electrodes, and electrodes 4d for forming t-strip lines are formed by silver metallization or the like. The input coupling capacitance is the input electrode 4e.

and the strip line electrode 4d, and the output coupling capacitance is formed by the output electrode 4c and the strip line electrode 4d. An electrode 4e for forming a ground electrode is provided on the back surface of the substrate by silver metallization or the like. In FIG. 4, dielectric coaxial resonators 1a, lb, lc
, the center metal fitting 2 of the ld is the through hole 4a of the sub-transmission line board 4,
Hole 3 provided in coupling capacitor board 3 via 4b
B is inserted and soldered. or.

The center fittings 2 of the dielectric coaxial resonators 1a and ld are soldered to the sub-transmission line board 4. The input/output terminal 5 is inserted into the hole 3a of the coupling capacitor board 3 and soldered.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional technology, in order to install the sub-transmission line board 4, the dielectric coaxial resonators 1a, lb, lc.

A sufficient space is required between the LD and the coupling capacitor substrate 3, which poses a problem in that the dielectric filter becomes taller.

The present invention is intended to solve these problems, and it is an object of the present invention to provide a dielectric filter that is small and has high attenuation characteristics.

(Means for Solving the Problems) In order to solve the above problems, the dielectric filter of the present invention connects the SIR dielectric coaxial resonator to the coupling capacitor board through the through hole of the sub-transmission line board. It has a structure that

(Function) With this technical means, the sub-transmission line board can be constructed in the space of the SIR dielectric coaxial resonator, and a dielectric filter having a sub-transmission line with a low-height structure is constructed.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a sectional view of a dielectric filter according to an embodiment of the present invention, and FIGS. 2(A) to 2(C) show a sub-transmission line board 8 in the same embodiment. The sub-transmission line board 8 is made of a dielectric board with excellent high frequency characteristics, and has a hole 8a for inserting the connection terminal 11 and a hole 8b for passing the SIR dielectric coaxial resonator. On the surface of the substrate, electrodes 8ci and 8c for forming input electrodes and output electrodes, and electrode 8d for forming a strip line are formed by silver metallization or the like. The input coupling capacitance is formed by the input electrode 8c1 and the strip line 8d, and the output coupling capacitance is formed by the output electrode 8c1.
c, and the strip line 8d. Further, on the back surface of the substrate, an electrode 8e for forming a ground electrode is provided by silver metallization or the like. Figure 3 (A)-(C
) shows the coupling capacitor substrate 7 in the above embodiment, which is made of a dielectric substrate with excellent high frequency characteristics such as alumina, and has a hole 7c for inserting the center fitting 9;
Hole 7a for inserting connection terminal 11 and input/output terminal 1
A hole 7b for inserting 0 is provided. On the surface of the substrate are electrodes 7d, 7e, 7 for forming coupling capacitance.
f is applied by silver metallization or the like. The coupling capacitance between the SIR dielectric coaxial resonance and the input/output terminal is 7d between the front and back electrodes.
and 7g. The coupling capacitance between SIR dielectric coaxial resonators is between electrodes 7d and 7e, 7e and 7 on the same surface.
f, formed by 7f and 7d. FIG. 1 is a sectional view of a four-stage dielectric filter constructed using the sub-transmission line board 8 and the coupling capacitor board 7. S.I.R.
The dielectric coaxial resonators 6a, 6b, 6c, and 6d are made of dielectric rectangular tubes, and silver metallization or the like is applied to one end surface other than the open end surface, and the entire outer peripheral surface and inner peripheral surface. The SIR dielectric coaxial resonator penetrates through the hole 8b of the sub-transmission line board 8, and the center metal fitting 9 made of metal for connecting to the coupling capacitor board 7 connects the SIR dielectric coaxial resonator 6a, 6b,
The inner conductors 6c and 6d are inserted into the holes 7d of the coupling capacitor board 7, respectively, and soldered with solder 12. The input/output terminal 10 made of metal is inserted into the hole 7b of the coupling capacitor board 7 and soldered with solder 12. Coupling capacitor board 7 and sub-transmission line board 8
Connecting fittings 11 made of metal are inserted into the holes 7a of the coupling capacitor board 7 and the holes 8a of the sub-transmission line board 8, respectively, and are soldered with solder 12.

In addition, the ground electrode 8e of the sub-transmission line board 8 is soldered to the external electrodes of the SIR dielectric coaxial resonators 6a, 6b, 6c, and 6d, and the ground side part of the case is bent to form the sub-transmission line board 8. Fix it and solder it.

This resulted in a better grounding condition and improved high frequency characteristics in the attenuation range.

(Effects of the Invention) As described above, according to the present invention, the height is reduced by providing a configuration in which the SIR dielectric coaxial resonator is passed through the hole of the sub-transmission line board and connected to the coupling capacitor board. It is possible to provide a dielectric filter with a high attenuation characteristic due to the shape.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a dielectric filter in an embodiment of the present invention, and FIGS. 2(A) to (C) are top, side, and bottom views of a sub-transmission line board in an embodiment of the present invention, Figure 3 (
A) to (C) are a top view, a side view, and a bottom view of a coupling capacitor board according to an embodiment of the present invention, FIG. 4 is a sectional view of a dielectric filter in a conventional example, and FIGS. )
6 shows a top view, a side view, and a bottom view of a sub-transmission line board according to a conventional example, and FIGS. 6A to 6C show a top view, a side view, and a bottom view of a coupling capacitor board according to a conventional example. 6a, 6b, 6c, 6d-S IR dielectric coaxial resonator, 7... Coupling capacitor board, 8... Sub-transmission line board, 9... Center metal fitting, lo... Input/output terminal. 11... Connection terminal.

Claims (1)

[Claims] A plurality of quarter-wavelength SIR dielectric coaxial resonators are disposed through a first dielectric substrate having a plurality of through holes and forming a coupling capacitor and a strip line, and the SIR dielectric A dielectric filter characterized in that it is connected to a second dielectric substrate having a coupling capacity of a coaxial resonator, and the first dielectric substrate and the second dielectric substrate are electrically connected in parallel.