JPH03150902A - Dielectric filter - Google Patents

Abstract

PURPOSE:To obtain a dielectric filter with less insertion loss by widening a surface area of a resonance slot, that is, a surface of the metallized slot. CONSTITUTION:Plural resonator slots 11-15 running on a dielectric base 10 in the broadwise direction are provided along the lengthwise direction in parallel and the resonator slots 11-15 are formed while starting from one side face of the dielectric base 10 but not reaching the other side face. Furthermore, the odd number order resonator slots 11, 13, 15 and the even number order resonator slots 12, 14 of the resonator slots 11-15 are provided interdigitally, the resonator slots 11, 13, 15 are penetrated to one base side face and the resonator slots 12, 14 are penetrated through the other base side face. Then the metallized conductor layer 18 is applied respectively to the bottom face, the side face of the dielectric base 10 and the resonator slots 11-15. Since the surface area of the resonator slots 11-15 is increased in this way, the dielectric filter with less insertion loss is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dielectric filter used in a transmitting/receiving circuit, such as a car telephone.

[Conventional technology]

For example, dielectric filters are used as filters in transmitting and receiving circuits in mobile radio communications such as car telephones and multi-channel access radios, as well as in microwave multiplex radio communications. Substrate type and block type dielectric filters are known as this type of dielectric filter, and an interdigital type is shown in FIG. 4 as a typical example.

In the dielectric filter shown in FIG. 4, a conductive layer is provided on the entire bottom surface of the dielectric substrate 40 to function as a shorting surface. Further, on the upper surface of the dielectric substrate 40, a pair of comb-shaped metallization layers are provided, which are electrically connected to the conductive layer on the bottom surface via conductive layers applied to both opposing longitudinal sides of the dielectric substrate 40, respectively, and are made of metallization that is intricate with each other. Conductive layer patterns 41 and 42 are provided. In this dielectric filter, a resonator is constructed between the comb-teeth portions (11) facing each other, and terminals 43 and 44 are led out from the comb-teeth portions located at both ends via a pattern conductive to the comb-teeth portions. . Incidentally, bins 45 to 48 are attached to the four corners of the dielectric substrate 40 and also serve as ground conductors.

[Problem to be solved by the invention]

However, this type of conventional dielectric filter has a drawback that insertion loss is relatively large when used by inserting it into a signal transmitting/receiving circuit.

Therefore, an object of the present invention is to provide a dielectric filter with lower insertion loss.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a plurality of resonator grooves on the upper surface of a dielectric substrate, starting from one side surface and not reaching the other side surface, approximately at right angles to the longitudinal direction of the substrate. The formed grooves and conversely formed grooves starting from the other side and not reaching one side are alternately arranged in a zigzag pattern, and the side and back surfaces of the dielectric substrate and the resonator groove are metallized. conductive layers that are electrically conductive to each other are formed on the dielectric substrate, and a conductive layer is formed on the dielectric substrate, one end of which faces the open end of the resonator groove that becomes the input/output end of the resonator groove, and the other end of which is electrically connected to the input/output terminal. This is a dielectric filter in which an input/output pattern is formed.

[For production]

In the dielectric filter described above, the surface area of the resonator groove, that is, the surface area of the groove formed by metallization can be increased, and a dielectric filter with low insertion loss can be constructed.

〔Example〕

FIG. 1 shows an embodiment of a dielectric filter according to the present invention. In this dielectric filter, a plurality of resonator grooves 11 running in the width direction on the dielectric substrate 10,
12, 13 and 14, 15 are arranged in parallel along the longitudinal direction. These resonator grooves 11 to 15 are formed starting from one side of the dielectric substrate 10 and not reaching the other side. In addition, these resonator grooves 11 to 15
In this case, the odd-numbered resonator grooves 11, 13, and 15 and the even-numbered resonator grooves 12.14 alternate left and right in a zigzag shape, that is, the resonator grooves 11 and 13.15 penetrate through one side surface of the substrate, A resonator groove 12.14 passes through the other substrate side.

The bottom and side surfaces of the dielectric substrate 10 and each resonator groove 11
15 are each provided with a conductive layer 16 made of metallization, as shown by a matte pattern.

The bottom and side surfaces of the dielectric substrate 10, together with a lid (not shown) placed thereon, are used at ground potential. Each of the resonator grooves 11 to 15 has one end connected to the side surface of the dielectric substrate 10 to form a short-circuited end, and the other end terminated halfway to the side surface to form an open end.

A terminal pin 1 is provided at the end of the dielectric substrate 10 by penetrating it.
7.18 is provided. As shown in FIG.
It is configured as a non-conductive part 19 without a conductive layer on the back side of the terminal pin 17 , 18 , so that the terminal pins 17 , 18 are insulated from the conductive layer 16 .

On the dielectric substrate 10, input and output cover turns 20 and 21 formed by metallizing conductive layers are integrally formed between the open ends of the resonator grooves 11 and 15 at both ends and the terminal pins 1, 7 and 18, respectively. There is. One end of the input/output cover turn 20, 21 faces the open end of the resonator groove 11.degree. 15, and the other end is electrically connected to the terminal pin 17.degree. 18.

According to the above configuration, first, a resonator is constructed around each of the resonator grooves 11 to 15, and a dielectric filter is constructed in which adjacent resonators are capacitively coupled to each other. Furthermore, the open end of the resonator groove 11.15 and the opposing input/output pattern 20.21 are capacitively coupled, and as a result, a dielectric filter with terminals led out via the input/output capacitor is formed. It will be configured.

According to the above configuration, a desired dielectric filter is formed on one dielectric substrate 10, and furthermore, a desired dielectric filter is formed on one dielectric substrate 10.
A terminal will be led out via an input/output capacitor formed above. Moreover, according to the above configuration, since the surface area of each resonator groove can be made relatively large, a dielectric filter with low insertion loss can be provided here.

FIG. 3 shows a modified embodiment of the invention.

In this embodiment, chip capacitors 30. for frequency adjustment are provided as necessary between each open end of the resonator groove 12, 13 and the conductive layer on the side surface of the substrate opposite thereto.
31 are connected.

Otherwise, there is no difference from the embodiment shown in FIG. This embodiment also achieves the above-mentioned functions and effects.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a dielectric filter with low insertion loss can be constructed on one dielectric substrate.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing one embodiment of the present invention.
FIG. 3 is a bottom view of the main parts of the dielectric filter shown in the figure, FIG. 3 is a perspective view of the main parts showing another embodiment of the present invention, and FIG. 4 is a perspective view of a conventional dielectric filter. 10...Dielectric substrate, 11.12.13.14°15
... Resonator groove, 16... Conductive layer, 17.18...
Terminal pin, 19... Non-conductive part, 20.21... Input/output cover turn.

Claims (1)

[Claims] A plurality of resonator grooves are formed on the top surface of a dielectric substrate, starting from one side and not reaching the other side, almost at right angles to the longitudinal direction of the substrate, and vice versa. Grooves formed starting at the beginning and not reaching one side surface are alternately arranged in a zigzag pattern, and a conductive layer is provided on the side and back surfaces of the dielectric substrate and the resonator groove so as to be electrically conductive with each other by metallization. , further forming on the dielectric substrate an input/output pattern consisting of a conductive layer, one end of which faces the open end of the resonator groove serving as the input/output end of the resonator groove, and the other end of which is electrically connected to the input/output terminal. dielectric filter.