CN110212273B

CN110212273B - Dual-band duplexer based on substrate integrated waveguide

Info

Publication number: CN110212273B
Application number: CN201910541156.3A
Authority: CN
Inventors: 许锋; 李玉颖; 张玉华
Original assignee: Nanjing University of Posts and Telecommunications
Current assignee: Nanjing University of Posts and Telecommunications
Priority date: 2019-06-20
Filing date: 2019-06-20
Publication date: 2021-01-19
Anticipated expiration: 2039-06-20
Also published as: CN110212273A

Abstract

The invention discloses a dual-band duplexer based on a substrate integrated waveguide, which comprises a filter dielectric substrate, a top metal layer arranged on the upper surface of the filter dielectric substrate, a bottom metal layer arranged on the lower surface of the filter dielectric substrate, and a metal layer arranged between the upper surface of the filter dielectric substrate and the lower surface of the filter dielectric substrate, wherein T-shaped output ports are arranged on the metal layers on the upper surface of the filter dielectric substrate and the lower surface of the filter dielectric substrate, and an input feed network is arranged on the metal layer in the middle. The invention has simple design structure and easy industrial processing, firstly introduces a miniaturized double-frequency SIW double-frequency duplexer, and solves the problem that the filter has relatively large size to a great extent. And secondly, an intermediate metal layer input feed network structure is introduced, so that the gain based on the SIW filter is further increased, and a foundation is laid for improving the passband gain and the return loss of the double-frequency SIW filter.

Description

Dual-band duplexer based on substrate integrated waveguide

Technical Field

The invention relates to a dual-band duplexer based on a substrate integrated waveguide, which can be used in the technical field of millimeter waves.

Background

In high frequency applications, microstrip lines often fail due to excessively small wavelengths and excessively high tolerance requirements. The traditional metal waveguide is large in size and difficult to integrate with other microwave and millimeter wave circuits in a plane. Since the substrate integrated waveguide is a quasi-closed planar waveguide structure similar to a common metal waveguide, it almost strictly eliminates mutual interference of different parts in a circuit due to radiation and a guided-wave mode in the substrate, in addition to having planar integration characteristics similar to a microstrip transmission line. Meanwhile, the planar microwave and millimeter wave circuit has good compatibility with active devices, is convenient for planar integration and miniaturization, has the advantages of small volume, light weight, simple assembly, easy processing, low cost and the like which are not possessed by the traditional waveguide, and can be used for designing a plurality of planar microwave and millimeter wave circuits with high Q values and low loss.

However, the introduction of the substrate integrated waveguide-based double-layer double-frequency duplexer reduces the size of the filter, improves the return loss of the filter, and provides a feasible idea for improving the performance of the SIW-based filter.

Disclosure of Invention

The present invention is directed to solve the above problems in the prior art, and provides a dual band duplexer based on a substrate integrated waveguide.

The purpose of the invention is realized by the following technical scheme: the dual-band duplexer based on the substrate integrated waveguide comprises a filter medium substrate, a top metal layer and a bottom metal layer, wherein the top metal layer is arranged on the upper surface of the filter medium substrate, the bottom metal layer is arranged on the lower surface of the filter medium substrate, the metal layers are arranged between the upper surface of the filter medium substrate and the lower surface of the filter medium substrate, T-shaped output ports are arranged on the metal layers on the upper surface of the filter medium substrate and the lower surface of the filter medium substrate, and an input feed network is arranged on the metal layers in the middle.

Preferably, metal through holes are formed in the periphery of the dielectric substrate, each metal through hole, the filter dielectric substrate, the top metal layer and the bottom metal layer form an SIW cavity structure, a feeder line of 50 Ω is arranged in the middle, and the width of the feeder line can be obtained according to the medium; the input/output port of the SIW filter dielectric substrate is formed by converting a microstrip line into a coplanar waveguide, wherein the length and the width of a gap of the coplanar waveguide are determined according to a feeder line of 50 omega;

preferably, the feed network of the input port is located in the middle of the middle metal layer, the T-shaped output port is located in the middle of the upper and lower surfaces, and the dielectric substrate is a rectangular dielectric substrate.

Preferably, the artificial magnetic conductor has a cut-out circular ring and a criss-cross metal surface on the upper surface, and a metal plate on the lower bottom surface.

Preferably, the position of the feed point of the filter is in the middle of the middle metal layer.

Preferably, the SIW cavity filter is rectangular in shape.

Preferably, the metal through hole rows are arranged on four sides of the cavity on the SIW cavity filter, two sides of the coupling window and two sides of the microstrip.

Preferably, the impedance of each microstrip line is 50 ohms.

Compared with the prior art, the invention adopting the technical scheme has the following technical effects: the invention has simple design structure and easy industrial processing, firstly introduces a miniaturized double-frequency SIW double-frequency duplexer, and solves the problem that the filter has relatively large size to a great extent. And secondly, an intermediate metal layer input feed network structure is introduced, so that the gain based on the SIW filter is further increased, and a foundation is laid for improving the passband gain and the return loss of the double-frequency SIW filter.

Drawings

Fig. 1 is a schematic top view of a dual-band SIW duplexer according to the present invention.

FIG. 2 is a 3D schematic diagram of the structure of a dual-band SIW duplexer of the present invention

Fig. 3 is a schematic top-level structure diagram of the dual-band SIW duplexer of the present invention.

Fig. 4 is a schematic diagram of an intermediate metal layer structure of the dual-band SIW duplexer of the present invention.

Fig. 5 is a schematic diagram of the lower layer structure of the dual-band SIW duplexer of the present invention.

Fig. 6 is a waveform diagram of S parameter simulation of the dual-band SIW duplexer of the present invention.

Detailed Description

Objects, advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments. The embodiments are merely exemplary for applying the technical solutions of the present invention, and any technical solution formed by replacing or converting the equivalent thereof falls within the scope of the present invention claimed.

The invention discloses a dual-band duplexer based on substrate integrated waveguide, as shown in fig. 1 and fig. 2, the dual-band duplexer comprises an upper surface metal patch 2, a lower surface metal patch 4 and a middle metal layer 3 of an SIW duplexer, a medium 6 is arranged between the upper metal layer and the lower metal layer, metal through holes 1 are carved on the upper surface and the lower surface and on the periphery of the middle metal layer to form an SIW cavity structure, the cavities are coupled through a coupling window 7, and the upper surface and the lower surface are provided with T-shaped output ports 5.

The invention firstly introduces the input feed arranged on the middle metal layer, and simultaneously saves the debugging cost, reduces the complexity of the process manufacture and improves the return loss of the filter because the upper and lower coupling mechanisms do not bring signal attenuation and loss. The invention has simple structure, easy processing and good performance, and lays a foundation for researching high-gain and miniaturized filters in the future.

Each layer of the double-layer substrate integrated waveguide is provided with a double-cavity structure, the substrate integrated waveguide is a novel microwave transmission line form, and the field propagation of the waveguide is realized on the upper medium substrate and the lower medium substrate by utilizing the metal through holes.

The upper and lower surfaces of the double-layer substrate integrated waveguide are formed by ideal electric conductors (pec), and the middle layer is made of metal copper. The duplexer is characterized in that a SIW cavity framework is formed by grounding plates on the upper surface and the lower surface, metal through holes are formed in the periphery of the grounding plates, a feed network is arranged in the middle layer, and the upper surface and the lower surface are connected with a channel and an output port in a T shape to provide a pole for each channel filter.

The distance between the metal through holes is determined according to the requirement, and the length of the coupling window between the cavities on the same layer is determined according to the frequency requirement. The feed network of the input port is arranged in the middle of the middle metal layer, and the T-shaped output port is arranged in the middle of the upper surface and the lower surface. The artificial magnetic conductor is characterized in that the upper surface of the artificial magnetic conductor is provided with a dug-out circular ring and a cross metal surface, the lower bottom surface of the artificial magnetic conductor is a metal plate, and the feed point of the filter is positioned in the middle of the middle metal layer.

Metal through holes are formed in the periphery of the rectangular dielectric substrate, the metal through holes in the periphery, the dielectric substrate, the top metal layer and the bottom metal layer form an SIW cavity structure, a feeder line of 50 ohms is arranged in the middle, and the width of the feeder line is obtained according to the medium;

the input and output port of the SIW dielectric substrate is formed by converting a microstrip line into a coplanar waveguide, wherein the length and the width of a slot of the coplanar waveguide are determined according to a feeder line of 50 omega. The distance between the through holes in the metal through hole row is determined according to the requirement.

The shape of the SIW cavity filter is rectangular, and the metal through hole rows are arranged on four sides of the upper cavity of the SIW cavity filter, two sides of the coupling window and two sides of the microstrip. The impedance of one microstrip line is 50 ohms.

The technical scheme of the invention is further explained in detail by the following specific embodiments:

in the embodiment of the invention, the duplexer adopts a Rogers 5880 dielectric plate, the dielectric constant of the dielectric plate is 2.2, and the single-layer thickness of the dielectric plate is 0.508 mm; the impedance of one microstrip line is 50 ohms, and the microstrip line is used as the input end of the dual-frequency SIW duplexer.

Example 1

As shown in fig. 4, a wave port is on the middle metal layer of the SIW cavity, that is, one microstrip line is on the middle metal layer of the two dielectric slabs, two equal slots are respectively disposed on two sides of the microstrip line, the wave port is formed by converting the microstrip line into the coplanar waveguide, metal through holes are disposed along two sides of the equal slot, the same metal through holes are disposed on the other three sides, and the distances between the two through holes are equal. And a T-shaped output port is arranged in the centers of the upper surface and the lower surface of the dual-frequency SIW duplexer to realize the power division of signals. The S parameter simulation waveform shown in FIG. 6 has the double frequency points of 11.6GHz and 13.5GHz respectively, the return loss of more than 20dB and 22dB respectively, and good working performance.

Example 2

As shown in fig. 3 and 5, the duplexer is composed of two upper and lower layers of dual cavities, the middle metal layer is used as the isolation layer of the upper and lower layers, each cavity is composed of metal through holes around the dielectric substrate and the upper and lower metal layers, and signal transmission is realized between the cavities on the same layer through the coupling window. FIG. 6 is a simulated waveform diagram of S parameters of a compact dual-band duplexer with a double-layer substrate integrated waveguide, wherein the dual-frequency points are respectively 11.6GHz and 13.5GHz, the return loss is respectively greater than 20dB and 22dB, the insertion loss is less than-1 dB, and the compact dual-band duplexer has good working performance.

The invention aims to provide a dual-band duplexer based on a substrate integrated waveguide, which solves the problem of low pass-band gain of an SIW filter and lays a foundation for the future research of filters with higher pass-band gain.

The invention has various embodiments, and all technical solutions formed by adopting equivalent transformation or equivalent transformation are within the protection scope of the invention.

Claims

1. The dual-band duplexer based on the substrate integrated waveguide is characterized in that: the filter medium substrate comprises a filter medium substrate, a top metal layer and a bottom metal layer, wherein the top metal layer and the bottom metal layer are respectively arranged on the upper surface of the filter medium substrate;

the feed network of the input port is arranged in the middle of the middle metal layer, the T-shaped output port is arranged in the middle of the upper surface and the lower surface, and the dielectric substrate is a rectangular dielectric substrate.

2. The substrate integrated waveguide-based dual-band duplexer of claim 1, wherein: metal through holes are formed in the periphery of the dielectric substrate, each metal through hole, the filter dielectric substrate, the top metal layer and the bottom metal layer form an SIW cavity structure, a feeder line with the thickness of 50 ohms is arranged in the middle, and the width of the feeder line can be obtained according to media; the input and output port of the SIW filter dielectric substrate is formed by converting a microstrip line into a coplanar waveguide, wherein the length and the width of a slot of the coplanar waveguide are determined according to a feeder line of 50 ohms.

3. The substrate integrated waveguide-based dual-band duplexer of claim 1, wherein: the position of the feed point of the filter is in the middle of the middle metal layer.

4. The substrate integrated waveguide-based duplexer of claim 2, wherein: the shape of the SIW cavity filter is rectangular.

5. The substrate integrated waveguide-based duplexer of claim 2, wherein: the metal through hole rows are arranged on four sides of the cavity on the SIW cavity filter, two sides of the coupling window and two sides of the microstrip.

6. The substrate integrated waveguide-based duplexer of claim 2, wherein: the impedance of each microstrip line is 50 ohms.