CN218941062U

CN218941062U - Low-frequency small-size dielectric filter

Info

Publication number: CN218941062U
Application number: CN202222829657.1U
Authority: CN
Inventors: 苗青雷
Original assignee: Jiaxing Runjie Electronics Co ltd
Current assignee: Jiaxing Runjie Electronics Co ltd
Priority date: 2022-10-26
Filing date: 2022-10-26
Publication date: 2023-04-28
Anticipated expiration: 2032-10-26

Abstract

The utility model discloses a low-frequency small-size dielectric filter, which comprises a shell, wherein an input end and an output end are arranged on two sides of the shell; a plurality of PCB bonding pads are welded in the shell, a plurality of capacitors are connected in series between the input end and the output end through the PCB bonding pads, a dielectric resonator is connected between adjacent capacitors, the other end of the dielectric resonator is grounded, and a pair of capacitors to ground are connected between the adjacent capacitors; and the open end of the dielectric resonator is connected with a capacitance to ground. The utility model welds the capacitance to the ground at the open end of the dielectric resonator, can reduce the frequency of the resonator under the condition of not changing the size of the dielectric resonator, not only meets the use requirement of a low-frequency dielectric filter, but also is convenient for workers to assemble.

Description

Low-frequency small-size dielectric filter

Technical Field

The utility model relates to the technical field of filters, in particular to a low-frequency small-size dielectric filter.

Background

If the low-frequency small-size filter is implemented by an LC filter circuit, the insertion loss of the narrow-band filter is relatively large. If the dielectric filter circuit is adopted for implementation, the size of the dielectric resonator is large, and the implementation is difficult because of the forming process of the dielectric resonator.

As shown in fig. 4, the circuit diagram of the conventional dielectric filter is that a plurality of capacitors C11 to C14 are connected in series on a main circuit, dielectric resonators F11 to F13 are connected between adjacent capacitors, and the other ends of the dielectric resonators F11 to F13 are grounded. When the frequency is 350M, the length of the dielectric resonator reaches 22.5mm (the dielectric constant 91 of the resonator), and when the frequency of the dielectric filter is reduced from 350M to 280M, the size of the dielectric resonator is lengthened to 28mm, so that the whole volume of the filter is enlarged, the difficulty of the manufacturing process is increased, and the suitability is reduced.

Disclosure of Invention

In order to solve the problems, the utility model provides a low-frequency small-size dielectric filter, which can reduce the frequency of the dielectric filter under the condition that the size of a dielectric resonator is unchanged and is convenient to operate.

For this purpose, the technical scheme of the utility model is as follows: a low-frequency small-size dielectric filter comprises a shell, wherein an input end and an output end are arranged on two sides of the shell; a plurality of PCB bonding pads are welded in the shell, a plurality of capacitors are connected in series between the input end and the output end through the PCB bonding pads, a dielectric resonator is connected between adjacent capacitors, the other end of the dielectric resonator is grounded, and a pair of capacitors to ground are connected between the adjacent capacitors; and the open end of the dielectric resonator is connected with a capacitance to ground.

Preferably, the open end of the dielectric resonator is connected with the PCB bonding pad between the adjacent capacitors through a conductor, and the PCB bonding pad between the adjacent capacitors is soldered with a grounding capacitor, that is, the open end of the dielectric resonator is connected with the grounding capacitor.

Preferably, the whole ceramic material that is of dielectric resonator, the dielectric resonator outside has four rectangle sides and two square terminal surfaces, and dielectric resonator inside cavity, and inside, four rectangle sides and one of them square terminal surface all are equipped with silver coating, and another square terminal surface is open end, inserts the conductor as the pin in the hole of open end, and the PCB pad between the adjacent electric capacity is connected to the other end of pin.

The filter of the utility model is 1/4 wavelength, and the dielectric resonator has a square end surface without silver coating, thereby forming an open end, and the frequency of the dielectric resonator can be reduced from 350M to 280M under the condition of unchanged size after the capacitance to ground is connected to the open end of the dielectric resonator.

Preferably, insulators are embedded in holes on two sides of the shell to serve as an input end and an output end, and inner conductors of the input end insulator and the output end insulator extend out of the shell.

Preferably, the filter circuit comprises a capacitor C1, a capacitor C2, a capacitor C3 and a capacitor C4 which are connected in series; a dielectric resonator F1 is connected between the capacitor C1 and the capacitor C2, and a grounding capacitor CP1 is welded at the open end of the dielectric resonator F1; a dielectric resonator F2 is connected between the capacitor C2 and the capacitor C3, and a grounding capacitor CP2 is welded at the open end of the dielectric resonator F2; a dielectric resonator F3 is connected between the capacitor C3 and the capacitor C4, and a grounding capacitor CP3 is welded at the open end of the dielectric resonator F3.

Compared with the prior art, the utility model has the beneficial effects that: the open end of the dielectric resonator is welded with the capacitance to the ground, so that the frequency of the resonator can be reduced under the condition that the size of the dielectric resonator is not changed, the use requirement of a low-frequency dielectric filter is met, and the assembly of workers is facilitated.

Drawings

The following is a further detailed description of embodiments of the utility model with reference to the drawings

FIG. 1 is a circuit block diagram of the present utility model;

FIG. 2 is a waveform diagram of a filter circuit according to the present utility model;

FIG. 3 is a schematic diagram of a simulation circuit of the present utility model;

fig. 4 is a circuit diagram of a dielectric filter according to the prior art.

Detailed Description

In the description of the present utility model, it should be noted that, for the azimuth words such as the terms "center", "transverse (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the azimuth and positional relationships are based on the azimuth or positional relationships shown in the drawings, only for convenience of describing the present utility model and simplifying the description, but do not indicate or imply that the apparatus or element to be referred to must have a specific azimuth, be constructed and operated in a specific azimuth, and should not be construed as limiting the specific protection scope of the present utility model.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features. Thus, the definition of "a first", "a second" feature may explicitly or implicitly include one or more of such feature, and in the description of the present utility model, the meaning of "a number", "a number" is two or more, unless otherwise specifically defined.

See the drawings. The small-size dielectric filter of this embodiment includes casing 1, and the both sides hole of casing 1 embeds there is the insulator, acts as input S1 and output S2, and the inside cavity that is equipped with of casing places PCB pad, electric capacity, dielectric resonator, and input insulator and output insulator inner conductor stretch out the casing.

A plurality of PCB bonding pads are arranged in the shell, a plurality of capacitors are connected in series between the input end and the output end through the PCB bonding pads, a dielectric resonator is connected between the adjacent capacitors, and the other end of the dielectric resonator is grounded. The dielectric resonator is integrally made of ceramic, four rectangular side faces and two square end faces are arranged on the outer side of the dielectric resonator, the dielectric resonator is hollow, silver coatings are arranged in the dielectric resonator, the four rectangular side faces and one square end face of the four rectangular side faces are provided with silver coatings, the other square end face is an open end, a conductor is inserted into a hole of the open end to serve as a pin, the other end of the pin is connected with a PCB bonding pad between adjacent capacitors, and the PCB bonding pad is welded with a grounding capacitor, so that the open end of the dielectric resonator is connected with the grounding capacitor.

The filter of this embodiment is 1/4 wavelength, and then the dielectric resonator has a square end surface without silver coating, so as to form an open end, and after the capacitance to ground is connected to the open end of the dielectric resonator, the frequency of the dielectric resonator can be reduced, and under the condition of unchanged size, the frequency of the dielectric filter is reduced from 350M to 280M.

Specifically, the filter circuit comprises a capacitor C1, a capacitor C2, a capacitor C3 and a capacitor C4 which are connected in series; the input end S1 is connected with the capacitor C1 through the PCB bonding pad P1, and the output end S2 is connected with the capacitor C4 through the PCB bonding pad P2;

the capacitor C1 and the capacitor C2 are connected in series through a PCB bonding pad P3, one end of a dielectric resonator F1 is connected to the PCB bonding pad P3, and the other end of the dielectric resonator F1 is grounded; a conductor is inserted into the open end hole of the dielectric resonator F1 as a pin, the other end of the pin is connected with a PCB pad P3, and a grounding capacitor CP1 is soldered on the PCB pad P3.

The capacitor C2 and the capacitor C3 are connected in series through a PCB bonding pad P4, one end of a dielectric resonator F2 is connected to the PCB bonding pad P4, and the other end of the dielectric resonator F2 is grounded; and a conductor is inserted into the open end hole of the dielectric resonator F2 to serve as a pin, the other end of the pin is connected with a PCB bonding pad P4, and a grounding capacitor CP2 is welded on the PCB bonding pad P4.

The capacitor C3 and the capacitor C4 are connected in series through a PCB bonding pad P5, one end of a dielectric resonator F3 is connected to the PCB bonding pad P5, and the other end of the dielectric resonator F3 is grounded; and a conductor is inserted into the open end hole of the dielectric resonator F3 to serve as a pin, the other end of the pin is connected with a PCB bonding pad P5, and a grounding capacitor CP3 is welded on the PCB bonding pad P5.

The capacitance value of the capacitor C1 and the capacitor C4 is 3.2pF, and the capacitance value of the capacitor C2 and the capacitor C3 is 0.8pF; the capacitance value of the ground capacitor CP1 is 24pF, the capacitance value of the ground capacitor CP2 is 24pF, and the capacitance value of the ground capacitor CP3 is 22pF.

The filter is 1/4 wavelength, then the dielectric resonator has an end surface without silver coating, thus forming an open end, the end surface of the open end of the dielectric resonator is provided with a hole, one end of the grounding capacitor extends into the hole and is electrically connected with the internal silver coating, and the other end of the grounding capacitor is grounded. After the capacitance to ground is connected to the open end of the dielectric resonator, the frequency of the dielectric resonator can be reduced, and the frequency of the dielectric filter is reduced from 350M to 280M under the condition of unchanged size.

The waveform diagram of this embodiment is shown in fig. 2, and the technical index parameters are as follows:

the above description is only a preferred embodiment of the present utility model, and the protection scope of the present utility model is not limited to the above examples, and all technical solutions belonging to the concept of the present utility model belong to the protection scope of the present utility model. It should be noted that modifications and adaptations to the present utility model may occur to one skilled in the art without departing from the principles of the present utility model and are intended to be within the scope of the present utility model.

Claims

1. A low-frequency small-size dielectric filter comprises a shell, wherein an input end and an output end are arranged on two sides of the shell; the method is characterized in that: a plurality of PCB bonding pads are welded in the shell, a plurality of capacitors are connected in series between the input end and the output end through the PCB bonding pads, a dielectric resonator is connected between adjacent capacitors, the other end of the dielectric resonator is grounded, and a pair of capacitors to ground are connected between the adjacent capacitors; and the open end of the dielectric resonator is connected with a capacitance to ground.

2. A low frequency small scale dielectric filter as recited in claim 1, wherein: the open end of the dielectric resonator is connected with the PCB bonding pad between the adjacent capacitors through a conductor, and the PCB bonding pad between the adjacent capacitors is welded with a grounding capacitor, namely the open end of the dielectric resonator is connected with the grounding capacitor.

3. A low frequency small scale dielectric filter as defined in claim 2, wherein: the dielectric resonator is integrally made of ceramic, the outer side of the dielectric resonator is provided with four rectangular side surfaces and two square end surfaces, the interior of the dielectric resonator is hollow, silver coatings are arranged in the dielectric resonator, the four rectangular side surfaces and one square end surface are respectively provided with silver coatings, the other square end surface is an open end, a conductor is inserted into a hole of the open end to serve as a pin, and the other end of the pin is connected with a PCB bonding pad between adjacent capacitors.

4. A low frequency small scale dielectric filter as recited in claim 1, wherein: and insulators are embedded in holes at two sides of the shell and serve as an input end and an output end, and inner conductors of the input end insulator and the output end insulator extend out of the shell.

5. A low frequency small scale dielectric filter as recited in claim 1, wherein: the filter circuit comprises a capacitor C1, a capacitor C2, a capacitor C3 and a capacitor C4 which are connected in series; a dielectric resonator F1 is connected between the capacitor C1 and the capacitor C2, and a grounding capacitor CP1 is welded at the open end of the dielectric resonator F1; a dielectric resonator F2 is connected between the capacitor C2 and the capacitor C3, and a grounding capacitor CP2 is welded at the open end of the dielectric resonator F2; a dielectric resonator F3 is connected between the capacitor C3 and the capacitor C4, and a grounding capacitor CP3 is welded at the open end of the dielectric resonator F3.