CN117691324A - a band pass filter - Google Patents

Abstract

The invention discloses a band-pass filter, which belongs to the technical field of filters and aims to solve the problems of large volume, high cost and low suppression effect of existing band-pass filters. The bandpass filter includes: a ceramic carrier, the ceramic carrier has an outer surface; an outer electrode, the outer electrode includes an input end, an output end, a first ground end and a second ground end, and the outer electrodes are respectively arranged on On the outer surface of the ceramic carrier; a circuit module, which is arranged inside the ceramic carrier and connected to the external electrode through transmission wires. The invention has the advantages of small size, low cost, small insertion loss, extremely steep attenuation, good stability, high reliability, and easy integration of other circuits and modules.

Description

a band pass filter

Technical field

The present invention relates to the technical field of filters, and in particular to a bandpass filter.

Background technique

Current microwave systems are developing towards high integration, high performance and small size. As a key component in radio frequency and microwave systems, filters have a direct impact on system performance. The filter quality factor is expressed by the ratio of the filter's center frequency F and the -3dB bandwidth B, that is, Q=F/B, which describes the filter's ability to separate adjacent frequency components in the signal. The larger the quality factor Q, the stronger the resolution ability of the filter and the higher the degree of suppression of out-of-band spurious. Methods to improve the quality factor of filters in the prior art mainly include generating zero points through multipath effects, using step impedance resonant structures to extend the stopband, using the inversion of quarter-wavelength transmission to generate zero points, and using hybrid coupling structures to generate zero points. Way. However, common problems with filters implemented using these methods are that they have complex structures or are large in size, and are inconvenient to be integrated with other compact mobile communication terminals. Therefore, how to realize the high Q value, wide stopband and high suppression characteristics of the filter in the smallest possible volume is a current research hotspot and difficulty.

In recent years, the emergence of new materials and process technologies such as microelectromechanical system technology, high-temperature superconducting technology, low-temperature co-fired ceramic technology, photonic bandgap structures, and microwave monolithic integrated circuits have promoted the performance and volume of RF passive components such as filters. With continuous improvement, individual components can now achieve the size of conventional surface mount resistors and capacitors. However, integrating multiple inductors and capacitors in such a compact space to realize the resonant unit of the filter can easily introduce unnecessary parasitic coupling between equivalent components, increase the parasitic effects of mutual inductance and mutual capacitance, thereby reducing the efficiency of the filter. Quality factor, deteriorating the filter's out-of-band rejection level.

Contents of the invention

The object of the present invention is to provide a band-pass filter to solve the problems of existing band-pass filters that are large in size, high in cost and low in suppression effect.

The technical solutions of the present invention to solve the above technical problems are as follows:

The present invention provides a band-pass filter, which includes:

Ceramic carrier, the ceramic carrier has an outer surface, the outer surface includes a first outer surface, a second outer surface, a third outer surface and a fourth outer surface, the first outer surface and the second outer surface are parallel Set, the third outer surface and the fourth outer surface are arranged parallel;

External electrode, the external electrode includes: an input terminal, an output terminal, a first ground terminal and a second ground terminal; one of the input terminal and the output terminal is disposed on the first outer surface, and the other disposed on the second outer surface; one of the first ground terminal and the second ground terminal is disposed on the third outer surface, and the other is disposed on the fourth outer surface;

A circuit module is arranged inside the ceramic carrier and connected to the external electrode through a transmission wire.

Optionally, the circuit module includes a multi-layer circuit, and the multi-layer circuit includes a number of equivalent components. The several equivalent components include: ground equivalent inductance L1A, ground equivalent inductance L1B, equivalent inductance L2A, etc. Effective inductance L2B, grounding equivalent inductance L3A, grounding equivalent inductance L3B, grounding equivalent capacitance C1A, grounding equivalent capacitance C1B, grounding equivalent capacitance C2A, grounding equivalent capacitance C2B, equivalent capacitance C3A, equivalent capacitance C3B, Ground equivalent capacitance C4A, ground equivalent capacitance C4B, equivalent capacitance C5, equivalent capacitance C6, equivalent capacitance C7 and equivalent capacitance C8;

The multi-layer circuit is equivalent to an equivalent circuit, and the equivalent circuit includes:

The input end is simultaneously connected to the ground equivalent capacitance C1A, the ground equivalent inductance L1A and one end of the equivalent inductance L2A; the other end of the equivalent inductance L2A is simultaneously connected to the ground equivalent capacitance C2A, One end of the equivalent capacitor C3A, one end of the equivalent capacitor C6 and one end of the equivalent capacitor C7; the other end of the equivalent capacitor C3A is simultaneously connected to the ground equivalent capacitor C4A, the ground, etc. Effective inductor L3A, one end of the equivalent capacitor C5 and one end of the equivalent capacitor C8; the other end of the equivalent capacitor C7 is simultaneously connected to the other end of the equivalent capacitor C5 and the grounded equivalent capacitor C4B , the ground equivalent inductance L3B and one end of the equivalent capacitance C3B; the other end of the equivalent capacitance C8 is simultaneously connected to the other end of the equivalent capacitance C6, the other end of the equivalent capacitance C3B, and the other end of the equivalent capacitance C3B. One end of the grounding equivalent capacitance C2B and the equivalent inductance L2B; the other end of the equivalent inductance L2B is simultaneously connected to the grounding equivalent inductance L1B, the grounding equivalent capacitance C1B and the output end.

Optionally, multiple resonance units include:

Resonance unit U1in, the resonance unit U1in includes the equivalent capacitance C1A and the equivalent inductance L1A;

Resonance unit U1out, the resonance unit U1out includes the equivalent capacitance C1B and the equivalent inductance L1B;

Resonance unit U2in, the resonance unit U2in includes the equivalent capacitance C4A and the equivalent inductance L3A;

Resonance unit U2out includes the equivalent capacitance C4B and the equivalent inductance L3B.

Optionally, the multi-layer circuit includes a nine-layer circuit, wherein the first metal sheet of the first circuit layer includes a first side, a second side, a third side and a fourth side, and the first The edge and the second edge are arranged in parallel, any one of the first ground end and the second ground end is connected to the first edge, and the other is connected to the second edge; The thirty-fourth metal sheet of the ninth circuit layer includes a fifth side, a sixth side, a seventh side and an eighth side, the fifth side and the sixth side are arranged in parallel, and the Either one of the first ground terminal and the second ground terminal is connected to the fifth side, and the other is connected to the sixth side; the first metal sheet of the first circuit layer and the The first via hole group, the second via hole group, the third via hole group and the fourth via hole group between the thirty-fourth metal sheet of the ninth circuit layer are used to fix the first metal sheet and the third via hole group. The relative position of the thirty-four metal pieces;

The fifth via group includes a first part of the fifth via group and a second part of the fifth via group. The first part of the fifth via group is the first input conductive piece of the second circuit layer and the third Between the first metal sheet of a circuit layer; the second part of the fifth via group is between the 28th metal sheet of the eighth circuit layer and the first input conductive sheet of the second circuit layer;

The sixth via group includes a first part of the sixth via group and a second part of the sixth via group. The first part of the sixth via group is the first output conductive sheet of the second circuit layer and the second part of the sixth via group. between the first metal sheet of the first circuit layer; the second part of the sixth via group is the thirty-first metal sheet of the eighth circuit layer and the first input conduction of the second circuit layer between pieces;

The fifteenth metal piece includes a first part of the fifteenth metal piece and a second part of the fifteenth metal piece, and the first part of the fifteenth metal piece and the second part of the fifteenth metal piece pass through the tenth Microstrip connections in via three, via fourteen, and fourth circuit layer;

The ground equivalent inductance L1A is the first part of the fifth via group;

The ground equivalent inductance L1B is the first part of the sixth via group;

The equivalent inductance L2A is the second part of the fifth via group;

The equivalent inductance L2B is the second part of the sixth via group;

The ground equivalent inductance L3A is the seventh via group between the thirtieth metal sheet of the eighth circuit layer and the first metal sheet of the first circuit layer;

The ground equivalent inductance L3B is the eighth via group between the thirty-third metal sheet of the eighth circuit layer and the first metal sheet of the first circuit layer;

The ground equivalent capacitance C1A includes the thirty-fourth metal piece of the ninth circuit layer and the twenty-ninth metal piece of the eighth circuit layer;

The ground equivalent capacitance C1B includes the thirty-fourth metal piece of the ninth circuit layer and the thirty-second metal piece of the eighth circuit layer;

The ground equivalent capacitance C2A includes the thirty-fourth metal piece of the ninth circuit layer and the twenty-eighth metal piece of the eighth circuit layer;

The ground equivalent capacitance C2B includes the thirty-fourth metal piece of the ninth circuit layer and the thirty-first metal piece of the eighth circuit layer;

The equivalent capacitance C3A includes the sixth metal piece and the seventh metal piece of the fourth circuit layer, the twelfth metal piece of the fifth circuit layer, the eighteenth metal piece and the nineteenth metal piece of the sixth circuit layer, The twenty-sixth metal sheet of the seventh circuit layer, the twenty-eighth metal sheet and the thirtieth metal sheet of the eighth circuit layer;

The equivalent capacitance C3B includes the eighth metal piece and the ninth metal piece of the fourth circuit layer, the fourteenth metal piece of the fifth circuit layer, the twentieth metal piece of the sixth circuit layer, and The twenty-first metal sheet, the twenty-seventh metal sheet of the seventh circuit layer, the thirty-first metal sheet and the thirty-third metal sheet of the eighth circuit layer;

The equivalent capacitance C4A includes the thirty-fourth metal piece of the ninth circuit layer and the thirtieth metal piece of the eighth circuit layer;

The equivalent capacitance C4B includes the thirty-fourth metal piece of the ninth circuit layer and the thirty-third metal piece of the eighth circuit layer;

The equivalent capacitance C5 includes the twenty-second metal piece and the twenty-third metal piece of the sixth circuit layer, the sixteenth metal piece of the fifth circuit layer, and the fourth circuit layer. ten metal plates and eleven metal plates;

The equivalent capacitance C6 includes the twenty-fourth metal piece and the twenty-fifth metal piece of the seventh circuit layer, and the seventeenth metal piece of the sixth circuit layer;

The equivalent capacitance C7 includes the eighteenth metal piece and the twenty-first metal piece of the sixth circuit layer, and the thirteenth metal piece of the fifth circuit layer;

The equivalent capacitance C8 includes the nineteenth metal piece and the twentieth metal piece of the sixth circuit layer, the first part of the fifteenth metal piece of the fifth circuit layer, and the second part of the fifteenth metal piece. part, and the microstrip line of the fourth circuit layer.

Optionally, the via group is composed of multiple via holes, and the multiple via holes are connected in parallel to eliminate parasitic inductance.

Optionally, the circuit module includes multiple shielding units, and the multiple shielding units include:

Shielding unit R1A, the shielding unit R1A includes a second metal sheet of the second circuit layer, a first metal sheet of the first circuit layer, and a space between the second metal sheet and the first metal sheet. The ninth via group;

Shielding unit R1B, the shielding unit R1B includes a fourth metal sheet of the second circuit layer, a first metal sheet of the first circuit layer, and a space between the fourth metal sheet and the first metal sheet. The eleventh via group;

Shielding unit R2A, the shielding unit R2A includes the third metal sheet of the second circuit layer, the thirty-fifth metal sheet of the third circuit layer, the first metal sheet of the first circuit layer, and the third metal sheet of the second circuit layer. The tenth via hole group between the three metal sheets and the first metal sheet;

Shielding unit R2B, the shielding unit R2B includes the fifth metal sheet of the second circuit layer, the thirty-sixth metal sheet of the third circuit layer, the first metal sheet of the first circuit layer, and the a twelfth via hole group between the fifth metal sheet and the first metal sheet;

The shielding unit is used to separate the resonant unit to avoid parasitic coupling.

Optionally, the ceramic carrier is manufactured based on multi-layer printed circuit board technology or low-temperature co-fired ceramic technology or IPD technology or CMOS semiconductor technology;

The circuit modules are processed into chip components through lamination technology;

The outer surface of the ceramic carrier is provided with a mark, and the mark is placed close to the input end or the output end to identify the position of the input end or the output end.

Optionally, the embedded metal material used in the circuit module is copper or palladium silver.

Optionally, the thickness from the first circuit layer to the top layer of the bandpass filter is 1000um;

The thickness from the second circuit layer to the first circuit layer is 720um;

The thickness from the third circuit layer to the second circuit layer is 720um;

The thickness from the fourth circuit layer to the third circuit layer is 120um;

The thickness of the fifth circuit layer to the fourth circuit layer is 60um;

The thickness of the sixth circuit layer to the fifth circuit layer is 60um;

The thickness of the seventh circuit layer to the sixth circuit layer is 60um;

The thickness of the eighth circuit layer to the seventh circuit layer is 90um;

The thickness of the ninth circuit layer to the eighth circuit layer is 90um;

The thickness from the bottom layer of the bandpass filter to the ninth circuit layer is 90um.

Optionally, the relative dielectric constant of the ceramic carrier is 7.8, and the dielectric loss angle is 0.001.

The invention has the following beneficial effects:

1. The present invention adopts low-temperature co-fired ceramic technology and a multi-layer layout structure to ensure low cost while optimizing the coupling relationship of equivalent components in the vertical space and using parallel vias to generate near-upper sidebands. Multiple transmission zeros for high squareness factor and steep frequency response;

2. By integrating four resonant units, two capacitors to ground, two inter-stage series inductors, three inter-stage direct coupling capacitors and three inter-stage cross-coupling capacitors into the circuit module, the present invention has high suppression and wide resistance. Microwave characteristics of the belt;

3. The filter of the present invention has a small overall volume and is suitable for miniaturized radio communication equipment that has very strict requirements on volume and suppression;

4. The present invention forms a via group through parallel vias to eliminate parasitic coupling;

5. The present invention adopts standard patch packaging form to facilitate integration into various communication systems.

Description of the drawings

Figure 1 is a schematic diagram of the outer surface structure of a ceramic carrier of a bandpass filter provided by an embodiment of the present invention;

Figure 2 is a schematic diagram of the three-dimensional structure of the circuit module;

Figure 3 is the equivalent circuit diagram of the circuit module;

Figure 4 is a top view of the first circuit layer in the circuit module;

Figure 5 is a top view of the second circuit layer in the circuit module;

Figure 6 is a top view of the third circuit layer in the circuit module;

Figure 7 is a top view of the fourth circuit layer in the circuit module;

Figure 8 is a top view of the fifth circuit layer in the circuit module;

Figure 9 is a top view of the sixth circuit layer in the circuit module;

Figure 10 is a top view of the seventh circuit layer in the circuit module;

Figure 11 is a top view of the eighth circuit layer in the circuit module;

Figure 12 is a top view of the ninth circuit layer in the circuit module;

Figure 13 is an electrical performance curve diagram of the bandpass filter of the present invention;

Explanation of reference signs

1-Input terminal; 2-Output terminal; 3-First ground terminal; 4-Second ground terminal; 5-Identification; P1-First metal sheet; P2-Second metal sheet; P3-Third metal sheet; P4 - The fourth metal piece; P5 - the fifth metal piece; P6 - the sixth metal piece; P7 - the seventh metal piece; P8 - the eighth metal piece; P9 - the ninth metal piece; P10 - the tenth metal piece; P11- The eleventh metal piece; P12-the twelfth metal piece; P13-the thirteenth metal piece; P14-the fourteenth metal piece; P15.1-the first part of the fifteenth metal piece; P15.2-the fifteenth metal piece The second part of the metal piece; P16 - the sixteenth metal piece; P17 - the seventeenth metal piece; P18 - the eighteenth metal piece; P19 - the nineteenth metal piece; P20 - the twentieth metal piece; P21 - the twentieth metal piece Twenty-one metal pieces; P22-the twenty-second metal piece; P23-the twenty-third metal piece; P24-the twenty-fourth metal piece; P25-the twenty-fifth metal piece; P26-the twenty-sixth metal piece ;P27-the twenty-seventh metal piece;P28-the twenty-eighth metal piece;P29-the twenty-ninth metal piece;P30-the thirtieth metal piece;P31-the thirty-first metal piece;P32-the thirtieth metal piece Two metal sheets; P33-the thirty-third metal sheet; P34-the thirty-fourth metal sheet; P35-the thirty-fifth metal sheet; P36-the thirty-sixth metal sheet; H1-the first via group; H2- The second via group; H3 - the third via group; H4 - the fourth via group; H5 - the fifth via group; H6 - the sixth via group; H7 - the seventh via group; H8 - the eighth Via group; H9 - ninth via group; H10 - tenth via group; H11 - eleventh via group; H12 - twelfth via group; H13 - thirteenth via; H14 - tenth Four via holes; Pin1-the first input conductive piece; Pin2-the second input conductive piece; Pout1-the first output conductive piece; Pout2-the second output conductive piece.

Detailed ways

The principles and features of the present invention are described below with reference to the accompanying drawings. The examples cited are only used to explain the present invention and are not intended to limit the scope of the present invention.

The LTCC multilayer bandpass filter shown in Figures 1 to 12 includes a multilayer ceramic carrier, a circuit layer within the ceramic carrier, and external electrodes on the outer side walls. The multi-layer circuit of the filter can be built into the ceramic dielectric body based on the low-temperature co-fired ceramic process, and various equivalent components can be integrated on the three-dimensional circuit substrate to achieve miniaturization and high density of the circuit. Metal materials with high conductivity, such as silver and copper, can be used as conductor materials, which is beneficial to improving the quality factor of the circuit system. In order to improve the quality factor of the circuit system, the present invention uses palladium silver as the embedded metal material, which will not be oxidized during the sintering process and does not require electroplating protection. Those skilled in the art can adjust the embedded metal material according to actual needs.

The present invention provides a band-pass filter. As shown in Figure 1, the band-pass filter includes:

Ceramic carrier, the ceramic carrier has an outer surface, the outer surface includes a first outer surface, a second outer surface, a third outer surface and a fourth outer surface, the first outer surface and the second outer surface are arranged in parallel, the third outer surface and the third outer surface The four outer surfaces are arranged in parallel;

The ceramic carrier provided by the present invention has a volume of 4.5 mm × 3.2 mm × 2.0 mm, and is sintered and molded at a temperature of 890°C ± 20°C. The ceramic carrier has a relative dielectric constant of 7.8 and a dielectric loss angle of 0.001.

The external electrode includes: an input terminal 1, an output terminal 2, a first ground terminal 3 and a second ground terminal 4; one of the input terminal 1 and the output terminal 2 is provided on the first outer surface, and the other is provided on the first outer surface. On the second outer surface; one of the first ground terminal 3 and the second ground terminal 4 is arranged on the third outer surface, and the other is arranged on the fourth outer surface;

The circuit module is arranged inside the ceramic carrier and connected to the external electrode through transmission wires.

The ceramic carrier is used to build the frame of the bandpass filter. The external electrode is set on the outer surface of the ceramic carrier, and the circuit module is set inside the ceramic carrier. Ceramic materials are conducive to improving the quality factor of the circuit system and increasing the flexibility of circuit design.

As shown in Figure 2, the circuit module includes a multi-layer circuit. The multi-layer circuit includes a number of equivalent components. The several equivalent components include: ground equivalent inductance L1A, ground equivalent inductance L1B, equivalent inductance L2A, equivalent inductance L2B, Grounding equivalent inductance L3A, grounding equivalent inductance L3B, grounding equivalent capacitance C1A, grounding equivalent capacitance C1B, grounding equivalent capacitance C2A, grounding equivalent capacitance C2B, equivalent grounding capacitance C3A, equivalent grounding capacitance C3B, grounding equivalent capacitance C4A, ground equivalent capacitance C4B, equivalent capacitance C5, equivalent capacitance C6, equivalent capacitance C7 and equivalent capacitance C8;

The circuit module includes four resonant units, two capacitors to ground, two inter-stage series inductors, three inter-stage direct coupling capacitors and three inter-stage cross-coupling capacitors; these equivalent components are arranged in nine circuit layers, with different Circuit layers are connected through vias and/or via groups. Each resonant unit of the filter is separated by a columnar shielding structure to reduce unnecessary parasitic coupling.

Multi-layer circuits are equivalent to equivalent circuits. As shown in Figure 3, the equivalent circuits include:

Input terminal 1 is simultaneously connected to the grounded equivalent capacitor C1A, the grounded equivalent inductance L1A, and one end of the equivalent inductor L2A; the other end of the equivalent inductor L2A is simultaneously connected to the grounded equivalent capacitor C2A, one end of the equivalent capacitor C3A, and the equivalent capacitor C6 One end of the equivalent capacitor C7 and one end of the equivalent capacitor C7; the other end of the equivalent capacitor C3A is connected to the grounded equivalent capacitor C4A, the grounded equivalent inductor L3A, one end of the equivalent capacitor C5 and one end of the equivalent capacitor C8; the other end of the equivalent capacitor C7 The other end is simultaneously connected to the other end of the equivalent capacitor C5, the grounded equivalent capacitor C4B, the grounded equivalent inductance L3B and one end of the equivalent capacitor C3B; the other end of the equivalent capacitor C8 is simultaneously connected to the other end of the equivalent capacitor C6, the equivalent The other end of the capacitor C3B, the grounded equivalent capacitor C2B and one end of the equivalent inductor L2B; the other end of the equivalent inductor L2B is also connected to the grounded equivalent inductor L1B, the grounded equivalent capacitor C1B and the output terminal 2.

Equivalent components are constructed into equivalent circuits to realize the filtering function of the filter;

In order to ensure a smaller overall volume, the present invention uses a multi-layer layout structure and adopts a standard patch packaging form; however, this method is not unique, and those skilled in the art can make adjustments according to actual needs to meet the volume requirements. Can.

As a specific implementation, referring to Figures 4 to 12, several equivalent elements constitute multiple resonant units, and the multiple resonant units include:

Resonance unit U1in, which includes equivalent capacitance C1A and equivalent inductance L1A;

Resonance unit U1out, which includes equivalent capacitance C1B and equivalent inductance L1B;

Resonance unit U2in, which includes equivalent capacitance C4A and equivalent inductance L3A;

The resonant unit U2out includes an equivalent capacitor C4B and an equivalent inductor L3B.

The multi-layer circuit provided by the present invention includes a nine-layer circuit, wherein the first metal sheet of the first circuit layer includes a first side, a second side, a third side and a fourth side, and the first side and The second side is arranged in parallel, any one of the first ground terminal 3 and the second ground terminal 4 is connected to the first side, and the other is connected to the second side; the thirty-fourth metal sheet of the ninth circuit layer It includes the fifth side, the sixth side, the seventh side and the eighth side. The fifth side and the sixth side are arranged in parallel. Either end of the first ground terminal 3 and the second ground terminal 4 is connected to the first ground terminal 3 and the second ground terminal 4. Five edges are connected, and the other is connected to the sixth edge; the first via hole group and the second via hole group between the first metal sheet of the first circuit layer and the thirty-fourth metal sheet of the ninth circuit layer , the third via hole group and the fourth via hole group are used to fix the relative positions of the first metal sheet and the thirty-fourth metal sheet;

The fifth via group includes a first part of the fifth via group and a second part of the fifth via group. The first part of the fifth via group is the first input conductive piece of the second circuit layer and the first part of the first circuit layer. between the first metal sheet; the second part of the fifth via hole group is between the twenty-eighth metal sheet of the eighth circuit layer and the first input conductive sheet of the second circuit layer;

The first part and the second part of the fifth via group are respectively equivalent to two equivalent inductors;

The sixth via group includes a first part of the sixth via group and a second part of the sixth via group. The first part of the sixth via group is the first output conductive sheet of the second circuit layer and the first part of the first circuit layer. between the first metal sheet; the second part of the sixth via group is between the thirty-first metal sheet of the eighth circuit layer and the first input conductive sheet of the second circuit layer;

The first part and the second part of the sixth via group are respectively equivalent to two equivalent inductors;

One end of the first input conductive piece Pin1 is connected to the input terminal 1 on the external electrode, and the other end is connected to the first metal piece through the fifth via group;

One end of the first output conductive sheet Pout1 is connected to the output terminal 2 on the external electrode, and the other end is connected to the first metal sheet through the sixth via group;

One end of the second input conductive piece Pin2 is connected to the input terminal 1 on the external electrode;

One end of the second output conductive sheet Pout2 is connected to the output terminal 2 on the external electrode;

The equivalent inductance L1A is the first part of the fifth via group;

The equivalent inductance L1B is the first part of the sixth via group;

The equivalent inductance L2A is the second part of the fifth via group;

The equivalent inductance L2B is the second part of the sixth via group;

The equivalent inductance L3A is the seventh via hole group between the thirtieth metal sheet of the eighth circuit layer and the first metal sheet of the first circuit layer;

The equivalent inductance L3B is the eighth via group between the thirty-third metal sheet of the eighth circuit layer and the first metal sheet of the first circuit layer;

The equivalent capacitance C1A includes the thirty-fourth metal piece on the ninth circuit layer and the twenty-ninth metal piece on the eighth circuit layer; the thirty-fourth metal piece and the twenty-ninth metal piece are equivalent to ground through vertical coupling. Equivalent capacitance C1A;

The equivalent capacitance C1B includes the thirty-fourth metal piece on the ninth circuit layer and the thirty-second metal piece on the eighth circuit layer; the thirty-fourth metal piece and the thirty-second metal piece are equivalent to ground through vertical coupling. Equivalent capacitance C1B;

The equivalent capacitance C2A includes the thirty-fourth metal piece on the ninth circuit layer and the twenty-eighth metal piece on the eighth circuit layer; the thirty-fourth metal piece and the twenty-eighth metal piece are equivalent to ground through vertical coupling. Equivalent capacitance C2A;

The equivalent capacitance C2B includes the thirty-fourth metal sheet on the ninth circuit layer and the thirty-first metal sheet on the eighth circuit layer; the thirty-fourth metal sheet and the thirty-first metal sheet are equivalent to ground through vertical coupling. Equivalent capacitance C2B;

The equivalent capacitance C3A includes the sixth and seventh metal sheets of the fourth circuit layer, the twelfth metal sheet of the fifth circuit layer, the eighteenth and nineteenth metal sheets of the sixth circuit layer, the seventh The twenty-sixth metal sheet of the circuit layer, the twenty-eighth metal sheet and the thirtieth metal sheet of the eighth circuit layer; the sixth metal sheet, the seventh metal sheet, the twelfth metal sheet, the eighteenth metal sheet, The nineteenth metal piece, the twenty-sixth metal piece, the twenty-eighth metal piece and the thirtieth metal piece are equivalent to equivalent capacitance C3A through multi-layer vertical coupling;

The equivalent capacitance C3B includes the eighth metal piece and the ninth metal piece of the fourth circuit layer, the fourteenth metal piece of the fifth circuit layer, the twentieth metal piece and the twenty-first metal piece of the sixth circuit layer, The twenty-seventh metal sheet of the seventh circuit layer, the thirty-first metal sheet and the thirty-third metal sheet of the eighth circuit layer; the eighth metal sheet, the ninth metal sheet, the fourteenth metal sheet, the twentieth metal The sheet, the twenty-first metal sheet, the twenty-seventh metal sheet, the thirty-first metal sheet and the thirty-third metal sheet are equivalent to the equivalent capacitance C3B through multi-layer vertical coupling;

The equivalent capacitance C4A includes the thirty-fourth metal sheet of the ninth circuit layer and the thirtieth metal sheet of the eighth circuit layer; the thirty-fourth metal sheet and the thirtieth metal sheet are equivalent to the grounding equivalent capacitance through vertical coupling. C4A;

The equivalent capacitance C4B includes the thirty-fourth metal piece on the ninth circuit layer and the thirty-third metal piece on the eighth circuit layer; the thirty-fourth metal piece and the thirty-third metal piece are equivalent to ground through vertical coupling. Equivalent capacitance C4B;

The equivalent capacitance C5 includes the twenty-second metal piece and the twenty-third metal piece of the sixth circuit layer, the sixteenth metal piece of the fifth circuit layer, and the tenth and eleventh metal pieces of the fourth circuit layer. pieces; the twenty-second metal piece, the twenty-third metal piece, the sixteenth metal piece, the tenth metal piece and the eleventh metal piece are equivalent to the equivalent capacitance C5 through multi-layer vertical coupling;

The equivalent capacitance C6 includes the twenty-fourth metal sheet and the twenty-fifth metal sheet of the seventh circuit layer, and the seventeenth metal sheet of the sixth circuit layer; the twenty-fourth metal sheet, the twenty-fifth metal sheet and The seventeenth metal piece is equivalent to the equivalent capacitance C6 through vertical coupling;

The equivalent capacitance C7 includes the eighteenth metal piece and the twenty-first metal piece on the sixth circuit layer, and the thirteenth metal piece on the fifth circuit layer; the eighteenth metal piece, the twenty-first metal piece and the tenth metal piece on the fifth circuit layer. The three metal sheets are equivalent to equivalent capacitance C7 through vertical coupling;

The equivalent capacitance C8 includes the nineteenth metal sheet and the twentieth metal sheet of the sixth circuit layer, the first part of the fifteenth metal sheet and the second part of the fifteenth metal sheet of the fifth circuit layer, and the fourth circuit layer of microstrip lines; the nineteenth metal sheet, the twentieth metal sheet, the first part of the fifteenth metal sheet and the second part of the fifteenth metal sheet connected using the microstrip line are equivalent to equivalent capacitance through vertical coupling C8.

From this, it can be seen that in order to avoid parasitic coupling, the present invention uses eight vias in parallel to form a via group to reduce the parasitic parameters of its equivalent inductance, and sets up multiple shielding units to separate the resonant units; of course, This method is not the only one. The present invention does not limit the number of via holes in the via group and the number and position of the shielding units, and it is enough to avoid parasitic coupling to a limited extent.

The circuit module includes multiple shielding units, and the multiple shielding units include:

The shielding unit R1A includes a second metal sheet of the second circuit layer, a first metal sheet of the first circuit layer, and a ninth via group between the second metal sheet and the first metal sheet;

The shielding unit R1B includes a fourth metal sheet of the second circuit layer, a first metal sheet of the first circuit layer, and an eleventh via group between the fourth metal sheet and the first metal sheet;

The shielding unit R2A includes a third metal sheet of the second circuit layer, a thirty-fifth metal sheet of the third circuit layer, a first metal sheet of the first circuit layer, and the third metal sheet and the first metal sheet. The tenth via group between;

The shielding unit R2B includes the fifth metal sheet of the second circuit layer, the thirty-sixth metal sheet of the third circuit layer, the first metal sheet of the first circuit layer, and the fifth metal sheet and the first metal sheet. the twelfth via group between;

The shielding unit is used to separate the resonant unit and avoid parasitic coupling;

The ceramic carrier provided by the present invention is manufactured based on multi-layer printed circuit board technology or low-temperature co-fired ceramic technology or IPD technology or CMOS semiconductor technology;

The circuit module provided by the present invention is processed into chip components through lamination technology, which can be easily integrated into various communication systems;

The outer surface of the ceramic carrier is provided with a mark 5. The mark 5 is placed close to the input terminal 1 or the output terminal 2 to identify the position of the input terminal 1 or the output terminal 2.

The embedded metal material used in the circuit module is copper or palladium silver.

The thickness from the first circuit layer to the top layer of the bandpass filter is 1000um;

The thickness from the second circuit layer to the first circuit layer is 720um;

The thickness from the third circuit layer to the second circuit layer is 720um;

The thickness from the fourth circuit layer to the third circuit layer is 120um;

The thickness of the fifth circuit layer to the fourth circuit layer is 60um;

The thickness of the sixth circuit layer to the fifth circuit layer is 60um;

The thickness of the seventh circuit layer to the sixth circuit layer is 60um;

The thickness of the eighth circuit layer to the seventh circuit layer is 90um;

The thickness of the ninth circuit layer to the eighth circuit layer is 90um;

The thickness from the bottom layer of the bandpass filter to the ninth circuit layer is 90um.

As shown in Figure 13, the filter works in the Wi-Fi 5G frequency band, its passband frequency is 5170-5330MHz, and the loss in the passband is less than 2.5dB. The stopband suppression from 2400MHz to 2500MHz is greater than 40dB, and the stopband suppression from 5490MHz to 8000MHz is greater than 42dB. The above indicators reflect the filter's excellent quality factor, steep frequency response and extremely high stopband suppression effect.

The invention has the following beneficial effects:

1. The present invention adopts low-temperature co-fired ceramic technology and a multi-layer layout structure to ensure low cost while optimizing the coupling relationship of equivalent components in the vertical space and using parallel vias to generate near-upper sidebands. Multiple transmission zeros for high squareness factor and steep frequency response;

2. By integrating four resonant units, two capacitors to ground, two inter-stage series inductors, three inter-stage direct coupling capacitors and three inter-stage cross-coupling capacitors into the circuit module, the present invention has high suppression and wide resistance. Microwave characteristics of the belt;

3. The filter of the present invention has a small overall volume and is suitable for miniaturized radio communication equipment that has very strict requirements on volume and suppression;

4. The present invention forms a via group through parallel vias to eliminate parasitic coupling;

5. The present invention adopts standard patch packaging form to facilitate integration into various communication systems.

6. The bandpass filter provided by the present invention has excellent properties such as high Q value, small size, and high suppression, and is easy to integrate with other circuit modules. It has broad application prospects in the field of new generation wireless communications.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (10)

1. A bandpass filter, the bandpass filter comprising:

a ceramic carrier having an outer surface comprising a first outer surface, a second outer surface, a third outer surface, and a fourth outer surface, the first outer surface and the second outer surface being disposed in parallel, the third outer surface and the fourth outer surface being disposed in parallel;

an outer electrode, the outer electrode comprising: the input end (1), the output end (2), the first grounding end (3) and the second grounding end (4); one of the input end (1) and the output end (2) is arranged on the first outer surface, and the other is arranged on the second outer surface; one of the first grounding end (3) and the second grounding end (4) is arranged on the third outer surface, and the other is arranged on the fourth outer surface;

the circuit module is arranged inside the ceramic carrier and is connected with the external electrode through a transmission wire.

2. The bandpass filter according to claim 1, wherein the circuit module comprises a multi-layer circuit comprising a number of equivalent elements including: the equivalent inductance L1A, the equivalent inductance L1B, the equivalent inductance L2A, the equivalent inductance L2B, the equivalent inductance L3A, the equivalent inductance L3B, the equivalent capacitance C1A, the equivalent capacitance C1B, the equivalent capacitance C2A, the equivalent capacitance C2B, the equivalent capacitance C3A, the equivalent capacitance C3B, the equivalent capacitance C4A, the equivalent capacitance C4B, the equivalent capacitance C5, the equivalent capacitance C6, the equivalent capacitance C7 and the equivalent capacitance C8 are grounded;

the multi-layer circuit is equivalent to an equivalent circuit, the equivalent circuit comprising:

the input end (1) is simultaneously connected with one end of the grounding equivalent capacitor C1A, the grounding equivalent inductor L1A and the equivalent inductor L2A; the other end of the equivalent inductor L2A is simultaneously connected with the grounding equivalent capacitor C2A, one end of the equivalent capacitor C3A, one end of the equivalent capacitor C6 and one end of the equivalent capacitor C7; the other end of the equivalent capacitor C3A is simultaneously connected with the grounding equivalent capacitor C4A, the grounding equivalent inductor L3A, one end of the equivalent capacitor C5 and one end of the equivalent capacitor C8; the other end of the equivalent capacitor C7 is simultaneously connected with the other end of the equivalent capacitor C5, the grounding equivalent capacitor C4B, the grounding equivalent inductor L3B and one end of the equivalent capacitor C3B; the other end of the equivalent capacitor C8 is simultaneously connected with the other end of the equivalent capacitor C6, the other end of the equivalent capacitor C3B, the grounded equivalent capacitor C2B and one end of the equivalent inductor L2B; the other end of the equivalent inductor L2B is connected with the grounding equivalent inductor L1B, the grounding equivalent capacitor C1B and the output end (2) at the same time.

3. The bandpass filter according to claim 2, wherein the number of equivalent elements constitutes a plurality of resonant cells, a plurality of the resonant cells comprising:

the resonant unit U1in, wherein the resonant unit U1in comprises the equivalent capacitor C1A and the equivalent inductor L1A;

the resonant unit U1out comprises the equivalent capacitor C1B and the equivalent inductor L1B;

the resonant unit U2in, wherein the resonant unit U2in comprises the equivalent capacitor C4A and the equivalent inductor L3A;

and the resonant unit U2out comprises the equivalent capacitor C4B and the equivalent inductor L3B.

4. The band-pass filter according to claim 2, characterized in that the multi-layer circuit comprises nine layers of circuits, wherein the first metal sheet of the first circuit layer comprises a first side, a second side, a third side and a fourth side, said first side and said second side being arranged in parallel, either one of said first ground terminal (3) and said second ground terminal (4) being connected to said first side, the other being connected to said second side; the thirty-fourth metal sheet of the ninth circuit layer comprises a fifth side, a sixth side, a seventh side and an eighth side, wherein the fifth side and the sixth side are arranged in parallel, any one of the first grounding end (3) and the second grounding end (4) is connected with the fifth side, and the other is connected with the sixth side; a first via group, a second via group, a third via group and a fourth via group between the first metal sheet of the first circuit layer and the thirty-fourth metal sheet of the ninth circuit layer are used for fixing the relative positions of the first metal sheet and the thirty-fourth metal sheet;

the fifth via group includes a first portion of the fifth via group and a second portion of the fifth via group, the

The first part of the fifth via group is between the first input conducting chip of the second circuit layer and the first metal sheet of the first circuit layer; a second part of the fifth via group is arranged between a twenty-eighth metal sheet of an eighth circuit layer and a first input conducting sheet of the second circuit layer;

the sixth via group comprises a first part of the sixth via group and a second part of the sixth via group, wherein the first part of the sixth via group is between the first output conducting strip of the second circuit layer and the first metal sheet of the first circuit layer; a second part of the sixth via group is between a thirty-first metal sheet of the eighth circuit layer and a first input conductive sheet of the second circuit layer;

the fifteenth metal sheet comprises a first part of the fifteenth metal sheet and a second part of the fifteenth metal sheet, and the first part of the fifteenth metal sheet and the second part of the fifteenth metal sheet are connected through a thirteenth via hole, a fourteenth via hole and a microstrip line in the fourth circuit layer;

the grounding equivalent inductance L1A is a first part of the fifth via group;

the grounding equivalent inductance L1B is a first part of the sixth via group;

the equivalent inductance L2A is a second part of the fifth via group;

the equivalent inductance L2B is a second portion of the sixth via group;

the grounding equivalent inductance L3A is a seventh via group between a thirty-first metal sheet of the eighth circuit layer and a first metal sheet of the first circuit layer;

the grounding equivalent inductance L3B is an eighth via group between a thirty-third metal sheet of the eighth circuit layer and the first metal sheet of the first circuit layer;

the grounding equivalent capacitor C1A includes a thirty-fourth metal sheet of the ninth circuit layer and a twenty-ninth metal sheet of the eighth circuit layer;

the grounding equivalent capacitor C1B includes a thirty-fourth metal sheet of the ninth circuit layer and a thirty-second metal sheet of the eighth circuit layer;

the grounding equivalent capacitor C2A includes a thirty-fourth metal sheet of the ninth circuit layer and a twenty-eighth metal sheet of the eighth circuit layer;

the grounding equivalent capacitor C2B includes a thirty-fourth metal sheet of the ninth circuit layer and a thirty-first metal sheet of the eighth circuit layer;

the equivalent capacitor C3A includes a sixth metal sheet and a seventh metal sheet of the fourth circuit layer, a twelfth metal sheet of the fifth circuit layer, an eighteenth metal sheet and a nineteenth metal sheet of the sixth circuit layer, a twenty-sixth metal sheet of the seventh circuit layer, a twenty-eighth metal sheet and a thirty-first metal sheet of the eighth circuit layer;

the equivalent capacitor C3B includes eighth and ninth metal sheets of the fourth circuit layer, a fourteenth metal sheet of the fifth circuit layer, twenty-first and twenty-first metal sheets of the sixth circuit layer, twenty-seventh metal sheet of the seventh circuit layer, thirty-first and thirty-third metal sheets of the eighth circuit layer;

the equivalent capacitor C4A includes a thirty-fourth metal sheet of the ninth circuit layer and a thirty-fourth metal sheet of the eighth circuit layer;

the equivalent capacitor C4B includes a thirty-fourth metal sheet of the ninth circuit layer and a thirty-third metal sheet of the eighth circuit layer;

the equivalent capacitor C5 includes a twenty-second metal sheet and a twenty-third metal sheet of the sixth circuit layer, a sixteenth metal sheet of the fifth circuit layer, and a tenth metal sheet and an eleventh metal sheet of the fourth circuit layer;

the equivalent capacitor C6 includes a twenty-fourth metal sheet and a twenty-fifth metal sheet of the seventh circuit layer, and a seventeenth metal sheet of the sixth circuit layer;

the equivalent capacitor C7 includes an eighteenth metal sheet and a twenty-first metal sheet of the sixth circuit layer, and a thirteenth metal sheet of the fifth circuit layer;

the equivalent capacitance C8 includes nineteenth and twentieth metal pieces of the sixth circuit layer, first and second portions of fifteenth metal pieces of the fifth circuit layer, and a microstrip line of the fourth circuit layer.

5. The bandpass filter according to claim 4, wherein the group of vias is constituted by a plurality of vias, a plurality of the vias being connected in parallel for eliminating parasitic inductances.

6. The bandpass filter according to claim 4, wherein the circuit module comprises a plurality of shielding units, the plurality of shielding units comprising:

a shielding unit R1A, wherein the shielding unit R1A includes a second metal sheet of the second circuit layer, a first metal sheet of the first circuit layer, and a ninth via group between the second metal sheet and the first metal sheet;

a shielding unit R1B, wherein the shielding unit R1B includes a fourth metal sheet of the second circuit layer, a first metal sheet of the first circuit layer, and an eleventh via group between the fourth metal sheet and the first metal sheet;

a shielding unit R2A, wherein the shielding unit R2A includes a third metal sheet of the second circuit layer, a thirty-first metal sheet of the third circuit layer, a first metal sheet of the first circuit layer, and a tenth via group between the third metal sheet and the first metal sheet;

a shielding unit R2B, the shielding unit R2B including a fifth metal sheet of the second circuit layer, a thirty-sixth metal sheet of the third circuit layer, a first metal sheet of the first circuit layer, and a twelfth via group between the fifth metal sheet and the first metal sheet;

the shielding unit is used for separating the resonance units to avoid parasitic coupling.

7. A bandpass filter according to claim 1, characterized in that,

the band-pass filter is manufactured based on a multilayer printed circuit board process or a low-temperature co-fired ceramic technology or an IPD process or a CMOS semiconductor process;

the circuit module is processed into a patch element through a lamination technology;

the ceramic carrier is characterized in that a mark (5) is arranged on the outer surface of the ceramic carrier, and the mark (5) is arranged close to the input end (1) or the output end (2) and is used for distinguishing the position of the input end (1) or the output end (2).

8. The bandpass filter according to claim 1, wherein the circuit module employs embedded metal material that is copper or palladium-silver.

9. A bandpass filter according to claim 1, characterized in that,

the thickness from the first circuit layer to the top layer of the band-pass filter is 1000um;

the thickness from the second circuit layer to the first circuit layer is 720um;

the thickness from the third circuit layer to the second circuit layer is 720um;

the thickness from the fourth circuit layer to the third circuit layer is 120um;

the thickness from the fifth circuit layer to the fourth circuit layer is 60um;

the thickness of the sixth circuit layer to the fifth circuit layer is 60um;

the thickness from the seventh circuit layer to the sixth circuit layer is 60um;

the thickness of the eighth circuit layer to the seventh circuit layer is 90um;

the thickness of the ninth circuit layer to the eighth circuit layer is 90um;

the thickness from the bottom layer of the band-pass filter to the ninth circuit layer is 90um.

10. The bandpass filter according to claim 1, wherein the ceramic carrier has a relative dielectric constant of 7.8 and a dielectric loss angle of 0.001.