CN111326835B - Three-dimensional stacked SIW duplexer - Google Patents

Abstract

The invention discloses a SIW duplexer with a three-dimensional stacked structure, and relates to the field of microwave passive devices. The aim is to provide a SIW duplexer which is easy to miniaturize and integrate with high density and can realize vertical transmission of transmitting and receiving signals. The invention is realized by the following technical scheme: the technical mode of combining the laminated SIW filters and the planar transmission lines is adopted, the two laminated SIW filters for receiving and transmitting are formed by vertically stacking the SIW resonant cavities arranged on each dielectric layer, the receiving and transmitting input and output transmission lines are positioned on the top metal surface of the SIW duplexer, and form a T-shaped structure with the top receiving and transmitting combined signal planar transmission line after being bent; and the input and output ports of the SIW duplexer are positioned on different planes of the top layer and the bottom layer, and the input and output ports of the transceiving filter are respectively subjected to T-shaped combination and horizontal leading-out by a plurality of sections of plane transmission lines positioned on the top layer and the bottom layer, so that the SIW duplexer with the three-dimensional stacked structure meeting the practical application requirements of the tile-type active phased array antenna under the millimeter wave frequency band is formed.

Description

Three-dimensional stacked SIW duplexer

Technical Field

The invention relates to the field of microwave passive devices, in particular to a three-dimensional stacked structure SIW (substrate Integrated waveguide) SIW duplexer.

Background

The SIW duplexer is the main accessory of the different-frequency duplex radio station and the relay station, and has the function of isolating the transmitted signal from the received signal and ensuring that the receiving and the transmitting can work normally at the same time. It is composed of two groups of band-pass filters with different frequencies. Substrate Integrated Waveguide (SIW) technology has emerged as one of the emerging and hot spot technologies in the passive direction of microwaves in recent years. A substrate integrated waveguide filter is a filter implemented on a dielectric substrate that behaves like a rectangular waveguide filter but belongs to a planar circuit. The method has the characteristics of high quality factor, large power capacity, easy processing, easy integration and the like. The filter based on the substrate integrated waveguide SIW resonant cavity has the advantages of easy integration and miniaturization of a microstrip filter with a system, and also has the advantages of high Q value (namely low insertion loss) and high power capacity of the waveguide filter, so that the substrate integrated waveguide SIW filter is very suitable for being applied to a millimeter wave system. A Substrate Integrated Waveguide (SIW) microwave filter is one of the components commonly used in communication systems and wireless systems, and the quality of the performance thereof directly affects the quality of the whole system. The substrate integrated waveguide SIW has a basic structure that metal layers are coated on the upper and lower surfaces of a low-loss dielectric substrate, and metallized through holes are formed on the two sides of the substrate. The SIW has the advantages of a rectangular waveguide and a microstrip line, namely, has the advantages of low loss, high Q value, high power capacity, miniaturization, easy integration, and the like, and can be manufactured by the existing PCB or LTCC process. Because the thickness of the SIW-based resonant cavity is far smaller than the length and the width of the SIW-based resonant cavity, the coupling of the cavity of the SIW resonant cavity is mainly realized by opening holes of a cavity ground metal plate, opening windows of side wall metallization through holes, forming probes by the through holes and other structures. The SIW filters with different out-of-band response characteristics can be formed by direct coupling or cross coupling of a plurality of substrate integrated waveguide SIW resonant cavities and combined with the theoretical comprehensive knowledge of the microwave filters, and a large number of researchers have researched various microwave filters based on substrate integrated waveguide SIW resonators to form a series of design theories and design methods of the SIW filters. At present, full wave analysis, equivalent model method and experimental method are available for the quantitative analysis of the transmission characteristics of the substrate integrated waveguide SIW. The experimental method is to draw the actual field of the substrate integrated waveguide according to the actually measured electromagnetic parameters of the position in each field, and the result is the most accurate. But the method has long time consumption and high cost, and is rarely applied in practical application. Third-party simulation software based on full-wave analysis can conveniently determine electromagnetic parameters in the field of the SIW, accurately analyze a transmission model of the SIW and conveniently know the influence of each parameter of the SIW on the transmission characteristic of the SIW by establishing the model. The equivalent model method is to convert the design of the SIW device into the mature design of the waveguide device, and convert the problems in the immature design field into the mature design field by using the equivalent parameter design between the SIW and the waveguide, thereby reducing the difficulty of the problems and saving the time for solving the problems. The main design parameters of the substrate integrated waveguide are centered on the metal via width W, the metal via pitch P, the metal via diameter D, and the substrate thickness H. With the development of miniaturized integrated circuits, signals often need to be transferred between various transmission systems or miniaturized components, and such problems are also involved in SIWs. There are probably three ways of transferring the conversion involved between the SIW and the general transmission system. Firstly, the microstrip line is connected in a coplanar manner, and the structure only needs one layer of dielectric substrate. And secondly, the microstrip line and the SIW are respectively arranged on the medium substrates of different layers and are connected with different surfaces of the microstrip line, and the energy is transmitted by coupling of the through holes and the probes. And thirdly, coaxial connection with the coaxial line. The microstrip line connected with the microstrip line in a coplanar manner is an unbalanced transmission line gradually developed from parallel double lines. The transmission line is formed by a dielectric substrate and an overlying microstrip conductor strip. Because the dielectric substrate with higher dielectric constant is arranged between the conductor ribbon and the grounding plate, the electric field is mainly distributed in the dielectric region between the conductor ribbon and the grounding plate. At low frequency transmission, the quasi-TEM mode can be regarded as in-field transmission, and the radiation loss is small. In order to realize the coplanar connection between the SIW and the microstrip line, in addition to physical connection, the mode conversion must be performed on the main mode 10TE for SIW transmission and the quasi-TEM mode for microstrip line transmission, and meanwhile, the characteristic impedance of the microstrip line itself and the wave impedance of the SIW must be matched to satisfy the two conditions, so that the signal transmission can be performed. The 50 ohm microstrip line is directly connected with the SIW through a conical transition section, and mode matching and impedance are achieved simultaneously. Because it is time consuming to optimize the transition section directly, a simple equivalent model can be used directly to find a more ideal initial value.

The SIW duplexer is used in a microwave millimeter wave system, such as an active phased array antenna and other important passive devices, and consists of two band-pass filters of a receiving passband and a transmitting passband, wherein the two band-pass filters are positioned at a receiving pre-stage and a transmitting final stage of the microwave millimeter wave system. Performance indexes of the SIW duplexer such as insertion loss, port standing waves, transmit-receive isolation and the like determine key indexes of the microwave millimeter wave system such as receiving sensitivity, detection distance, transmit-receive isolation and the like to a great extent. The specific implementation mode of the SIW duplexer at present is distinguished by a PCB, LTCC, HTCC, a cavity and the like according to the process, and is distinguished by a microstrip form, a waveguide form, an LC form and the like according to the circuit structure. On the other hand, due to the progress of semiconductor processes and the development of microsystem technologies, microwave millimeter wave systems are currently developed toward high-density integration, miniaturization, high reliability, and low cost. Taking an active phased array antenna as an example, the active phased array antenna comprises two functional modules, namely an antenna radiation array surface and a T/R assembly, wherein the implementation framework of the active phased array antenna gradually develops from a brick type structure, in which the previous signal transmission direction is parallel to the device functional surface direction, to a tile type structure, in which the signal transmission direction is perpendicular to the device functional surface direction, and the signal transmission direction is changed from the previous XY plane to the Z-axis direction, so that the occupied plane area of the active phased array antenna can be greatly reduced, and 3D stacking is realized. The active phased-array antenna with the tile type structure can realize high-density integration of T/R components at a small array element interval, and is a mainstream integration framework of the existing phased-array antenna, particularly a millimeter wave frequency band. However, the input and output structures of the SIW duplexer composed of the SIW filters studied by a lot of references are all in the same plane, and two or more SIW resonators are juxtaposed in the XY plane. Under the millimeter wave frequency band, the planar arrangement of a plurality of resonant cavities can also occupy the area in the XY direction too much, and is limited by the 1/2 wavelength limitation of the array element spacing, so that the application requirement of the millimeter wave frequency band active phased array antenna small array element spacing cannot be met. In addition, the input and output SIW duplexer in the same plane does not meet the signal vertical transmission requirement of the tile type active phased array antenna. Therefore, SIWs reported in a large number of documents have great limitations in practical engineering applications of microwave millimeter wave systems such as active phased array antennas, and improvements are needed to meet the practical applications.

The invention is an improvement on the traditional input and output SIW duplexer with a planar structure.

Disclosure of Invention

In order to solve the problem that the SIW duplexer with a planar input-output structure cannot meet the requirements of small array element spacing and signal vertical transmission of an active phased array antenna under a millimeter wave frequency band, the invention provides the SIW duplexer with the three-dimensional stacking structure, which is easy to miniaturize and integrate with high density.

In order to achieve the purpose, the invention adopts a scheme of combining the vertical stacking of the SIW rectangular resonant cavity and a planar transmission line to realize the SIW duplexer with a three-dimensional stacking structure.

The above object of the present invention can be achieved by the following technical solutions: a three-dimensional stacked-Structure (SIW) duplexer comprising: the multilayer dielectric substrate comprises a transmitting laminatedSIW filter 4, a receiving laminatedSIW filter 5, a transmitting output signal plane transmission line 6, a receiving input signalplane transmission line 7, a transmitting-receiving combined signal plane transmission line 8, a transmitting input signalplane transmission line 9 and a receiving output signalplane transmission line 10, and is characterized in that: the transmitting laminatedSIW filter 4 and the receiving laminatedSIW filter 5 are formed by vertically stacking SIW resonant cavities formed by metalized throughholes 11 which are arranged in each dielectric layer in a rectangular mode; the transmitting output signal plane transmission line 6 and the receiving input signalplane transmission line 7 are positioned on the top metal surface of the SIW duplexer, extend out through the output and input of the transmitting laminatedSIW filter 4 and the receiving laminatedSIW filter 5, bend in opposite directions by 90 degrees, form a T-shaped structure with the top transmitting-receiving combined signal plane transmission line 8, and are led out to the top transmitting-receiving signalcommon end surface 3; the transmitting input signalplane transmission line 9 and the receiving output signalplane transmission line 10 are positioned on the bottom metal surface of the SIW duplexer, and the inputs and outputs of the transmitting laminatedSIW filter 4 and the receiving laminatedSIW filter 5 are respectively led out to the transmitting signalinput end surface 1 and the receiving signaloutput end surface 2 which are separately arranged on the bottom SIW duplexer in a parallel relationship, so that the SIW duplexer with the three-dimensional stacked structure meeting the practical application requirement of the tile-type active phased-array antenna under the millimeter wave frequency band is formed.

Compared with the prior art, the invention has the following beneficial effects.

Easy miniaturization and high-density integration. According to the invention, the transmission laminatedSIW filter 4 and the reception laminatedSIW filter 5 are vertically stacked based on the SIW resonant cavity formed by the rectangular arrangement metalized throughholes 11, and the transmission path of the signal is converted from the traditional plane transmission to the vertical transmission through thecoupling gap 12, so that the area of the SIW duplexer can be greatly saved on the XY plane, compared with the SIW duplexer with a plane transmission structure, the plane size can be reduced by more than 50%, and the miniaturization of a passive device is further realized. The transmitting signalinput end face 1, the receiving signaloutput end face 2 and the receiving and transmitting signalsharing end face 3 can be compatible with any planar transmission line of a microwave and millimeter wave system, such as a grounding coplanar waveguide, a microstrip line, a strip line and the like, so that high-density integration is facilitated.

Full-duplex vertical transmission of the transmit-receive signal can be achieved. The transmitting signalinput end face 1, the transmitting signalcommon end face 3 and the receiving signaloutput end face 2 of the transmitting and receiving signalcommon end face 3 are not on the same horizontal plane and are respectively arranged on the upper surface and the lower surface of the SIW duplexer to form a non-coplanar input and output structure, so that full-duplex vertical transmission of transmitting and receiving signals can be realized, and the structure of the tile-type active phased array antenna is met.

Drawings

Fig. 1 is a schematic three-dimensional structure diagram of a three-dimensional stacked-structure SIW duplexer of the present invention;

FIG. 2 is a bottom plan view of FIG. 1;

fig. 3 shows the actual measurement result of the SIW duplexer with the three-dimensional stacked structure according to the embodiment of the invention.

In the figure: 1 transmitting signal input terminal surface, 2 receiving signal output terminal surfaces, 3 receiving and transmitting signal sharing terminal surfaces, 4 transmitting laminated SIW filters, 5 receiving laminated SIW filters, 6 transmitting output signal plane transmission lines, 7 receiving input signal plane transmission lines, 8 receiving and transmitting combined signal plane transmission lines, 9 transmitting input signal plane transmission lines, 10 receiving output signal plane transmission lines, 11 metallized through holes and 12 coupling gaps.

Detailed Description

Refer to fig. 1 and 2. In a preferred embodiment described below, a three-dimensional stacked-structure SIW duplexer includes: the multilayer dielectric substrate comprises a transmitting laminatedSIW filter 4, a receiving laminatedSIW filter 5, a transmitting output signal plane transmission line 6, a receiving input signalplane transmission line 7, a transmitting-receiving combined signal plane transmission line 8, a transmitting input signalplane transmission line 9 and a receiving output signalplane transmission line 10, and is characterized in that: the transmitting laminatedSIW filter 4 and the receiving laminatedSIW filter 5 are formed by vertically stacking SIW resonant cavities formed by metalized throughholes 11 which are arranged in each dielectric layer in a rectangular mode; the transmitting output signal plane transmission line 6 and the receiving input signalplane transmission line 7 are positioned on the top metal surface of the SIW duplexer, extend out through the output and input of the transmitting laminatedSIW filter 4 and the receiving laminatedSIW filter 5, bend in opposite directions by 90 degrees, form a T-shaped structure with the top transmitting-receiving combined signal plane transmission line 8, and are led out to the top transmitting-receiving signalcommon end surface 3; the transmitting input signalplane transmission line 9 and the receiving output signalplane transmission line 10 are positioned on the bottom metal surface of the SIW duplexer, and the inputs and outputs of the transmitting laminatedSIW filter 4 and the receiving laminatedSIW filter 5 are respectively led out to the transmitting signalinput end surface 1 and the receiving signaloutput end surface 2 which are separately arranged on the bottom SIW duplexer in a parallel relationship, so that the SIW duplexer with the three-dimensional stacked structure meeting the practical application requirement of the tile-type active phased-array antenna under the millimeter wave frequency band is formed.

In the preferred embodiment described below, the SIW duplexer with a three-dimensional stacked structure can be implemented by any multi-layer dielectric substrate processing technology such as silicon-based MEMS, HTCC, LTCC, multi-layer PCB, etc. The receiving and transmitting laminated SIW filter at least adopts a 3-layer SIW resonant cavity stacking structure, and any different stacking layers are adopted under the permission of process conditions or according to the index requirements of a microwave millimeter wave system on the SIW duplexer.

Transmitting signalinput terminal surface 1, received signaloutput terminal surface 2, send and receive signalsharing terminal surface 3 are located the vertical lateral wall department of SIW duplexer respectively, and wherein transmitting signalinput terminal surface 1 and received signaloutput terminal surface 2 are located the bottom of SIW duplexer, and send and receive signalsharing terminal surface 3 is located the top layer of SIW duplexer, have constituted the different face transmission structure that can realize the perpendicular transmission of send and receive signal full duplex.

The transmitting output signal plane transmission line 6 and the receiving input signalplane transmission line 7 on the top layer of the SIW duplexer adopt a form of a grounding coplanar waveguide transmission line (CPWG) with impedance of 50 ohms, and can also adopt forms of other types of plane transmission lines such as microstrip lines and strip lines according to the actual requirements of compatible microwave and millimeter wave systems. The length of the transmitting output signal plane transmission line 6 is about 1/4 waveguide wavelength at the center frequency of the receiving stackedSIW filter 5 and the receiving input signalplane transmission line 7 is about 1/4 waveguide wavelength at the center frequency of the transmitting stackedSIW filter 4. The transmitting output signal plane transmission line 6 and the receiving input signalplane transmission line 7 are in a U-shaped structure formed by converging after being bent for 90 degrees in opposite directions once, and are led out to the transmitting and receiving signalcommon end face 3 through a transmitting and receiving combined signal plane transmission line 8 with the characteristic impedance of 50 ohms. The length of the transmitting-receiving combined signal plane transmission line 8 is less than 300 μm and the shorter the transmission line is, the better the transmission line is, under the permission of process conditions, so as to reduce the size of the SIW duplexer with the whole three-dimensional stacked structure. The transmitting input signalplane transmission line 9 and the receiving output signalplane transmission line 10 which are positioned at the bottom layer of the SIW duplexer and are in parallel relation, and the characteristic impedance of which is 50 ohms adopt the form of a grounding coplanar waveguide transmission line (CPWG) to transmit signals, can also be compatible with the actual requirements of a microwave millimeter wave system, and adopt the forms of other types of plane transmission lines such as microstrip lines and strip lines. The transmitting input signalplane transmission line 9 and the receiving output signalplane transmission line 10 are respectively extended and led out to the transmitting signalinput end face 1 and the receiving signaloutput end face 2 of the bottom layer.

Signals in the transmitting laminatedSIW filter 4 and the receiving laminatedSIW filter 5 are vertically coupled and transmitted through thecoupling gaps 12 among the SIW rectangular resonant cavities of all layers, and the SIW rectangular resonant cavities of all layers have the same size and are completely aligned in the Z-axis direction. Based on the related theoretical knowledge of SIW resonator, TE is adopted_m0nThe mode is the resonance mode of the main mode, and the resonance frequency of the rectangular resonator determined by the length and width of the SIW rectangular resonator, i.e. the center frequency f of the transmitting/receiving laminated SIW filter₀：

This example uses TE with m-1 and n-1₁₀₁The mode is the primary mode of the SIW resonator, where c₀Is the speed of light in vacuum, epsilon_rIs the dielectric constant of the medium, W_effAnd L_effRespectively the corrected effective width and length of the SIW rectangular resonant cavity.

Referring to fig. 3, the test results show that: in the receiving passband range of the SIW duplexer with the three-dimensional stacked structure, the insertion loss is less than 1.8dB, and the in-band return loss is less than-12 dB; in the transmission passband range of Ka frequency band, the insertion loss is less than 2dB, the in-band return loss is less than-10 dB, and the SIW duplexer with the structure can meet the requirements of small array element spacing and vertical transmission of received and transmitted signals of the tile-type active phased array antenna under the millimeter wave frequency band and has higher engineering application value.

Claims (9)

1. A three-dimensional stacked-Structure (SIW) duplexer comprising: the multilayer dielectric substrate comprises a transmitting laminated SIW filter (4), a receiving laminated SIW filter (5), a transmitting output signal plane transmission line (6), a receiving input signal plane transmission line (7), a transmitting and receiving combined signal plane transmission line (8), a transmitting input signal plane transmission line (9) and a receiving output signal plane transmission line (10), and is characterized in that: the transmitting signal input end face (1), the receiving signal output end face (2) and the receiving and transmitting signal common end face (3) are respectively positioned on the longitudinal side walls of the SIW duplexer, wherein the transmitting signal input end face (1) and the receiving signal output end face (2) are positioned on the bottom layer of the SIW duplexer, and the receiving and transmitting signal common end face (3) is positioned on the top layer of the SIW duplexer, so that a different-surface transmission structure capable of realizing full-duplex vertical transmission of receiving and transmitting signals is formed; the transmitting laminated SIW filter (4) and the receiving laminated SIW filter (5) are formed by vertically stacking SIW resonant cavities formed by metalized through holes (11) which are arranged in each dielectric layer in a rectangular mode; the transmitting output signal plane transmission line (6) and the receiving input signal plane transmission line (7) are positioned on the top metal surface of the SIW duplexer, the transmitting output signal plane transmission line (6) extends out through the output of the transmitting laminated SIW filter (4), the receiving input signal plane transmission line (7) extends out through the input of the laminated SIW filter (5), bends at 90 degrees in opposite directions, forms a T-shaped structure with the top receiving and transmitting combined signal plane transmission line (8), and is led out to the top receiving and transmitting signal common end surface (3); the transmitting input signal plane transmission line (9) and the receiving output signal plane transmission line (10) are positioned on the bottom metal surface of the SIW duplexer, and the input and the output of the transmitting laminated SIW filter (4) and the receiving laminated SIW filter (5) are respectively led out to the transmitting signal input end surface (1) and the receiving signal output end surface (2) which are separately arranged on the bottom SIW duplexer in a parallel relation, so that the SIW duplexer with the three-dimensional stacked structure meeting the practical application requirement of the tile-type active phased array antenna under the millimeter wave frequency band is formed.

2. The three-dimensional stacked-structure SIW duplexer of claim 1, wherein: the SIW duplexer with the three-dimensional stacked structure can be realized by processing any multilayer dielectric substrate of silicon-based MEMS, HTCC, LTCC and multilayer PCB.

3. The three-dimensional stacked-structure SIW duplexer of claim 1, wherein: the receiving and transmitting laminated SIW filter at least adopts a 3-layer SIW resonant cavity stacking structure, and any different stacking layers are adopted under the permission of process conditions or according to the index requirements of a microwave millimeter wave system on the SIW duplexer.

4. The three-dimensional stacked-structure SIW duplexer of claim 1, wherein: the transmitting output signal plane transmission line (6) and the receiving input signal plane transmission line (7) which are positioned at the top layer of the SIW duplexer adopt a form of a grounding coplanar waveguide transmission line (CPWG) with 50 ohm impedance to transmit signals or are compatible with the actual requirements of a microwave millimeter wave system, and adopt forms of other types of plane transmission lines such as microstrip lines and strip lines.

5. The three-dimensional stacked-structure SIW duplexer of claim 1, wherein: the length of the transmitting output signal plane transmission line (6) is about 1/4 waveguide wavelength of the center frequency of the receiving stacked SIW filter (5), and the length of the receiving input signal plane transmission line (7) is about 1/4 waveguide wavelength of the center frequency of the transmitting stacked SIW filter (4); the transmitting output signal plane transmission line (6) and the receiving input signal plane transmission line (7) are in a U-shaped structure formed by converging after being bent for 90 degrees in opposite directions once, and are led out to a transmitting and receiving signal common end face (3) through a transmitting and receiving combined signal plane transmission line (8) with the characteristic impedance of 50 ohms.

6. The three-dimensional stacked-structure SIW duplexer of claim 1, wherein: the length of the transmitting-receiving combined signal plane transmission line (8) is less than 300 mu m, and the shorter the length is, the better the length is under the permission of process conditions, so that the size of the SIW duplexer with the whole three-dimensional stacked structure is reduced.

7. The three-dimensional stacked-structure SIW duplexer of claim 1, wherein: the planar transmission line (9) for transmitting input signals and the planar transmission line (10) for receiving output signals, which are positioned at the bottom layer of the SIW duplexer and are in parallel relation, have characteristic impedances of 50 ohms, adopt the form of a grounded coplanar waveguide transmission line (CPWG) to transmit signals, or are compatible with the actual requirements of a microwave millimeter wave system, and adopt the forms of other types of planar transmission lines such as microstrip lines and strip lines; the transmitting input signal plane transmission line (9) and the receiving output signal plane transmission line (10) are respectively extended and led out to the transmitting signal input end face (1) and the receiving signal output end face (2) of the bottom layer.

8. The three-dimensional stacked-structure SIW duplexer of claim 1, wherein: signals in the transmitting laminated SIW filter (4) and the receiving laminated SIW filter (5) are vertically coupled and transmitted through coupling gaps (12) among the SIW rectangular resonant cavities of all layers, and the SIW rectangular resonant cavities of all layers are identical in size and are completely aligned in the Z-axis direction.

9. The three-dimensional stacked-structure SIW duplexer of claim 1, wherein: based on the related theoretical knowledge of SIW resonator, TE is adopted_m0nThe mode is the resonance mode of the main mode, and the resonance frequency of the rectangular resonator determined by the length and width of the SIW rectangular resonator, i.e. the center frequency of the SIW filterf₀：

In the formula, c₀In order to obtain the light speed in vacuum,

is the dielectric constant of the medium and,W_effandL_effrespectively the corrected effective width and length of the SIW rectangular resonant cavity.

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