Miniaturized sum-difference network based on substrate integrated coaxial line

Abstract

The invention relates to a miniaturized sum-difference network based on substrate integrated coaxial lines. The miniaturized sum-difference network comprises four couplers and four sections of substrate integrated coaxial lines, wherein the couplers have the same structure and are based on the substrate integrated coaxial lines; the coupler is sequentially provided with 11 layers of structures from top to bottom, every two couplers are connected through a substrate integrated coaxial line, and the substrate integrated coaxial lines are connected with a signal output port of one coupler and a signal input port of the other coupler. The substrate integrated coaxial line is adopted for signal transmission, the structure is simple, signal transmission is stable, energy leakage is little, meanwhile, the multi-layer structure is adopted, the size is smaller, integration is easy, in addition, compared with a network made of microstrip lines under the same structure, the anti-interference capacity is high, the shielding effect is achieved, and energy can be better restrained from being radiated outwards.

Description

Technical Field

[0001] The invention belongs to microwave passive devices, and in particular relates to a miniaturized sum-difference network based on substrate integrated coaxial lines. Background Art

[0002] With the continuous development of radar communication technology, the requirements of communication systems for devices are getting higher and higher. How to reduce the size, quality and cost of microwave components while maintaining the excellent characteristics of components such as low loss and low interference has become a new challenge for researchers.

[0003] Target tracking radars usually use conical scanning, sequential beam conversion, and single pulse equiangular tracking technology. Conical scanning and sequential beam conversion generally have problems such as long signal acquisition time and large angle measurement errors for fast targets, and are easily interfered by local angle deception. The single pulse technology only needs to receive one echo pulse to extract angle error information. It takes a short time to obtain error information, has high angle measurement accuracy, and strong anti-interference ability. The key part of the single pulse radar is the RF single pulse processor, which is used to form sum signals, azimuth difference signals, and pitch difference signals, so it is also called a sum-difference network. As a necessary basic device in single pulse radars and phased arrays, the sum-difference network plays an important role in both military and civilian fields. Its design goals include miniaturization, low loss, and high amplitude phase balance.

[0004] Traditional sum-difference networks are generally divided into two types: planar and three-dimensional. The former is usually made with a 3dB bridge + delay line, but the introduction of the delay line leads to a large insertion loss and its amplitude and phase balance is difficult to ensure. The latter is usually made with a waveguide magic T, but the finished sum-difference network is large in size and not easy to integrate, and its open structure also brings difficulties to electromagnetic shielding design.

[0005] Therefore, it is necessary to design a sum-difference network with small size, low loss and high amplitude-phase balance. Summary of the invention

[0006] The object of the present invention is to provide a miniaturized sum and difference network based on substrate integrated coaxial line.

[0007] The technical solution to achieve the purpose of the present invention is: a miniaturized sum and difference network based on substrate integrated coaxial line, comprising four substrate integrated coaxial line couplers with the same structure and four equal length substrate integrated coaxial lines for connection;

[0008] The substrate integrated coaxial line coupler is provided with 11 layers of structure from top to bottom, including a first metal layer, a first dielectric layer, a first bonding layer, a second dielectric layer, a second metal layer, an adhesive layer, a third metal layer, a third dielectric layer, a second bonding layer, a fourth dielectric layer and a fourth metal layer;

[0009] A first metal conductive tape is provided in the middle of the second bonding layer;

[0010] There is a metallized via array around the first metal conductive strip, the via is cylindrical in shape, runs through all 11 layers of the structure, and the inner wall is metal;

[0011] The substrate integrated coaxial line based coupler comprises two signal input ports, two signal output ports and a signal transmission part;

[0012] A vertical signal transmission via hole is provided on the signal input port or the signal output port, and the signal is transmitted between different couplers by connecting the via hole;

[0013] The vertical signal transmission via is cylindrical in shape, surrounded by cylindrical dielectric vias, and penetrates the second dielectric layer, the second metal layer, the bonding layer, the third metal layer, the third dielectric layer, and the second bonding layer, and the inner wall is metal.

[0014] Compared with the prior art, the present invention has the following significant advantages: (1) The present invention adopts substrate-integrated coaxial line for signal transmission, which has a simple structure, stable signal transmission and less energy leakage; (2) The present invention adopts a multi-layer structure, which is smaller in size and easier to integrate than the traditional magic T-type structure; (3) Compared with the sum-difference network made of microstrip lines under the same structure, the present invention has better shielding effect, can better suppress the outward radiation of energy, and has stronger anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a top view of the miniaturized sum and difference network based on substrate integrated coaxial line of the present invention.

[0016] Figure 2 It is a three-dimensional structural diagram of a coupler based on a substrate-integrated coaxial line in a miniaturized sum-difference network based on a substrate-integrated coaxial line of the present invention.

[0017] Figure 3 The present invention is a three-dimensional structural diagram of a coupler based on a substrate-integrated coaxial line in a miniaturized sum and difference network based on a substrate-integrated coaxial line after removing the metallized via array.

[0018] Figure 4 It is a top view of a coupler based on a substrate integrated coaxial line in a miniaturized sum and difference network based on a substrate integrated coaxial line of the present invention.

[0019] Figure 5 It is a side schematic diagram of a coupler based on substrate integrated coaxial line in a miniaturized sum and difference network based on substrate integrated coaxial line of the present invention after removing the metallized via array.

[0020] Figure 6 It is a three-dimensional structural diagram of the miniaturized sum and difference network based on substrate-integrated coaxial line of the present invention.

[0021] Figure 7 This is a three-dimensional structural diagram of the miniaturized sum and difference network based on substrate integrated coaxial line of the present invention after removing the metallized via array.

[0022] Figure 8 The top view of the miniaturized and differential network marked ports based on the substrate-integrated coaxial line of the present invention.

[0023] Fig. 9 This is a 1-port input S parameter diagram of the miniaturized sum-difference network based on substrate integrated coaxial line of the present invention.

[0024] Fig.10 This is a test diagram of the insertion loss of the miniaturized and differential network based on the substrate-integrated coaxial line of the present invention.

[0025] Fig.11 and Fig.12 , Fig.13 This is a phase relationship diagram between the miniaturization and differential network ports based on the substrate integrated coaxial line of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below with reference to the accompanying drawings.

[0027] Combination Figure 1 , Figure 6 , Figure 7 and Figure 8 The present invention discloses a miniaturized sum-difference network based on substrate integrated coaxial line, comprising four substrate integrated coaxial line-based couplers with the same structure, wherein every two couplers are connected by substrate integrated coaxial line, and the substrate integrated coaxial line connects the signal output port of one coupler and the signal input port of another coupler, and both ends of the connecting line are located on the vertical signal transmission 203 of the input and output ports, and the characteristic impedance is 50Ohm.

[0028] Combination Figure 2 , Figure 3 , Figure 4 and Figure 5The substrate-integrated coaxial coupler has 11 layers of structure from top to bottom, including a first metal layer 101, a first dielectric layer 102, a first bonding layer 103, a second dielectric layer 104, a second metal layer 105, an adhesive layer 106, a third metal layer 107, a third dielectric layer 108, a second bonding layer 109, a fourth dielectric layer 110, and a fourth metal layer 111; a first metal conductive strip 201 is arranged in the middle of the second bonding layer 109; a metallized via array is arranged around the first metal conductive strip 201, the via is cylindrical in shape, runs through all the 11 layers of structure, and the inner wall is metal; the substrate The coupler of the substrate-integrated coaxial line includes two signal input ports 12, 13, two signal output ports 11, 14 and a signal transmission part; there is a vertical signal transmission via 203 on the signal input port 12, 13 or the signal output port 11, 14, and the signal can be transmitted between different couplers by connecting the via; the vertical signal transmission via 203 is cylindrical in shape, and there are cylindrical dielectric vias around it, which penetrate the second dielectric layer 104, the second metal layer 105, the bonding layer 106, the third metal layer 107, the third dielectric layer 108, and the second bonding layer 109, and the inner wall is metal.

[0029] Combination Figure 8 When working, the signal is input through ports 1, 2, 3, and 4, that is, the signal is input into the system through coupler 1 and coupler 2, and each coupler will make a difference and sum the two input signals; after the signal is input from port 1 and port 2, coupler 1 will generate a sum signal input into coupler 3, and coupler 1 will also generate a difference signal input into coupler 4; after the signal is input from port 3 and port 4, coupler 2 will generate a sum signal input into coupler 3, and coupler 2 will also generate a difference signal input into coupler 4; coupler 3 will make a difference and sum the signals input from coupler 1 and coupler 2, and coupler 3 will generate a sum signal output through port 5 and generate a difference signal output through port 6 Output; Coupler 4 will also perform difference and summation on the signals input by coupler 1 and coupler 2, and coupler 4 will generate a sum signal and output it through port 7, and generate a difference signal and output it through port 8; In general, the signal output by port 5 is equal to the sum of the input signals of input ports 1, 2, 3, and 4; the signal output by port 6 is equal to the sum of the input signals of input ports 1 and 2 minus the sum of the input signals of input ports 3 and 4; the signal output by port 7 is equal to the difference of the input signals of input ports 1 and 2 plus the difference of the input signals of input ports 3 and 4; the signal output by port 8 is equal to the difference of the input signals of input ports 1 and 2 minus the difference of the input signals of input ports 3 and 4.

[0030] Furthermore, the miniaturized sum and difference network based on substrate integrated coaxial line operates in the X-band, specifically in the 8.5 GHz-11 GHz band, and the optimal operating frequency is 10 GHz.

[0031] Furthermore, the structures of the four substrate-integrated coaxial line-based couplers of the miniaturized sum-difference network are the same, and every two couplers are connected by a substrate-integrated coaxial line, which connects the signal output port of one coupler to the signal input port of another coupler, and both ends of the connecting line are located on the vertical signal transmission (203) of the input and output ports, and the characteristic impedance is 50Ohm.

[0032] The present invention will be further described below in conjunction with specific embodiments.

[0033] Example

[0034] Combination Figure 2 , Figure 3 and Figure 5 The substrate integrated coaxial line coupler in this embodiment has 11 layers of structure from top to bottom, including a first metal layer 101, a first dielectric layer 102, a first bonding layer 103, a second dielectric layer 104, a second metal layer 105, an adhesive layer 106, a third metal layer 107, a third dielectric layer 108, a second bonding layer 109, a fourth dielectric layer 110, and a fourth metal layer 111. The first metal layer 101, the second metal layer 105, the third metal layer 107, and the fourth metal layer 111 are made of copper with a thickness of 0.036 mm, the first dielectric layer 102, the second dielectric layer 104, the third dielectric layer 108, and the fourth dielectric layer 110 are made of Rogers 4350 dielectric board with a relative dielectric constant of 3.55 and a thickness of 0.508 mm, and the first bonding layer 103, the adhesive layer 106, and the second bonding layer 109 are made of RO4450F dielectric board with a relative dielectric constant of 3.52 and a thickness of 0.101 mm.

[0035] Combination Figure 2 , Figure 3 , Figure 4 and Figure 5The second bonding layer 109 includes a first metal conduction band portion 201. The first metal conduction band portion 201 is made of copper with a thickness of 0.018 mm and has a ring-shaped and branched structure, including a first branch 31, a second branch 32, a third branch 33, and a fourth branch 34. The length of the metal conduction band ring is half of the working wavelength, and the width is one-quarter of the working wavelength. The metal conduction band width of the metal conduction band ring is 0.436 mm, and the corresponding characteristic impedance is 70.7 Ohm. The width of the metal conduction band at the branch is 0.824 mm, corresponding to a characteristic impedance of 50 Ohm. The second branch 32 and the fourth branch 34 are respectively located at the midpoints of two relatively narrow sides on the metal conduction band ring, and the length of the branch is one-eighth of the working wavelength. The first branch 31 and the third branch 33 are respectively located at the two quarter points of the same long side of the metal conduction band ring, and the length of the branch is one-eighth of the working wavelength. There is a metallized via array around the first metal conductive strip 201. The vias penetrate the entire 1-layer structure from top to bottom. The via diameter is 0.12 mm, the via spacing is 0.9 mm, and the distance between the via center and the microstrip centerline is 1.3 mm.

[0036] Combination Figure 3 and Figure 8 There are vertical signal transmission vias 203 on the second branch node 32 and the fourth branch node 34. The vertical signal transmission via 203 is cylindrical and passes through the second dielectric layer 104, the second metal layer 105, the bonding layer 106, the third metal layer 107, the third dielectric layer 108, and the second bonding layer 109 from top to bottom. It has a diameter of 0.824 mm and a height of 1.153 mm. The inner wall is made of metal. There are vias around the second metal layer 105 and the third metal layer 107 through which it passes. The vias have two diameters, 0.9 mm and 1.2 mm, respectively. The vias are filled with Rogers 4350 medium.

[0037] Combination Figure 6 and Figure 7 The miniaturized sum-difference network based on substrate integrated coaxial line is composed of 4 substrate integrated coaxial line couplers with the same structure and 4 equal lengths of substrate integrated coaxial line. The length of the substrate integrated coaxial line used for connection is 15.788mm, and the characteristic impedance is 50Ohm. There are two different shapes of connecting lines, namely straight line and bent type. Each section of transmission line connects the vertical signal transmission vias 203 of two couplers to each other. This topological structure can effectively reduce the overall size by expanding the transmission line in the longitudinal direction. In this embodiment, the overall size of the system is 23.0mm*18.8mm.

[0038] Combination Figure 8In this embodiment, the sum-difference network has a total of 8 ports, ports 1 to 4 are signal input ports, and ports 5 to 8 are signal output ports. The output signal of port 5 is (1+2+3+4); the output signal of port 6 is ((1+2)-(3+4)); the output signal of port 7 is ((1-2)+(3-4)); the output signal of port 8 is ((1-2)-(3-4)). The numbers in the above brackets represent the input signals of the corresponding numbered ports. Among them, port 5 represents the sum signal output terminal, port 6 and port 7 represent the pitch difference and azimuth difference signal output terminals respectively, and the output signal of port 8 has no practical meaning.

[0039] Fig. 9 S-parameter plot for the 1-port input of the sum and difference network. Fig. 9 It shows that the system operates at a center frequency of 10 GHz and an operating frequency band of 8.5 GHz to 11 GHz. The isolation at the center frequency is below -30 dB, and the isolation in the range of 8.5 to 11 GHz is below -15 dB, achieving good isolation between the four input ports in the frequency band.

[0040] Fig.10 This is the insertion loss test chart of the sum and difference network. The insertion loss at the center frequency of the sum and difference network is 6.1dB, the insertion loss error is about 0.1dB, the amplitude consistency is less than ±0.05dB, the insertion loss error in the working frequency band is about 1dB, the amplitude consistency is less than ±0.8dB, and the amplitude balance is good.

[0041] Fig.11 and Fig.12 , Fig.13 The diagram is a phase relationship diagram between the ports of the substrate integrated coaxial line sum and difference network. The phase error is within 1° at the center frequency of the sum and difference network, and within the working frequency band, the phase difference error is within 10°, and the phase balance is good. In summary, the miniaturized sum and difference network based on the substrate integrated coaxial line of the present invention is entirely composed of passive components, with a simple and reliable structure, stable signal transmission, and less energy leakage; at the same time, a multi-layer structure is adopted, and the system volume is smaller and easier to integrate than the traditional manufacturing method; in addition, compared with the microstrip line with the same structure, the present invention has a shielding effect, can suppress the outward radiation of energy, and has a strong anti-interference ability.

Claims

1. A miniaturized sum-difference network based on substrate-integrated coaxial line, characterized in that: It comprises four substrate integrated coaxial line couplers with the same structure and four sections of substrate integrated coaxial line with the same length for connection; The substrate integrated coaxial line coupler is provided with 11 layers of structure from top to bottom, including a first metal layer (101), a first dielectric layer (102), a first bonding layer (103), a second dielectric layer (104), a second metal layer (105), an adhesive layer (106), a third metal layer (107), a third dielectric layer (108), a second bonding layer (109), a fourth dielectric layer (110) and a fourth metal layer (111); A first metal conductive tape (201) is provided in the middle of the second bonding layer (109); A metallized via array is arranged around the first metal conductive strip (201), the via is cylindrical in shape, runs through all 11 layers of the structure, and the inner wall is made of metal; The substrate integrated coaxial line-based coupler comprises two signal input ports (12, 13), two signal output ports (11, 14) and a signal transmission part; A vertical signal transmission via (203) is provided on the signal input port (12, 13) or the signal output port (11, 14), and a signal is transmitted between different couplers by connecting the via; The vertical signal transmission via (203) is cylindrical in shape, has cylindrical dielectric vias around it, penetrates the second dielectric layer (104), the second metal layer (105), the bonding layer (106), the third metal layer (107), the third dielectric layer (108), and the second bonding layer (109), and has a metal inner wall.

2. The miniaturized sum-difference network based on substrate integrated coaxial line according to claim 1, characterized in that: Every two couplers are connected through a substrate integrated coaxial line, and the substrate integrated coaxial line connects a signal output port of one coupler and a signal input port of another coupler.

3. The miniaturized sum-difference network based on substrate integrated coaxial line according to claim 2, characterized in that: Both ends of the connection line are located on the vertical signal transmission (203) of the input and output ports, and the characteristic impedance is 50 ohms.

4. The miniaturized sum-difference network based on substrate integrated coaxial line according to claim 1, characterized in that: The first metal conduction band (201) has a ring-shaped and branched structure, including a first branch node (31), a second branch node (32), a third branch node (33), and a fourth branch node (34); the length of the metal conduction band ring is half of the working wavelength, the width is one quarter of the working wavelength, and the characteristic impedance of the metal conduction band ring is 70.7 ohms; the characteristic impedance of the metal conduction band at the branch node is 50 ohms; the second branch node (32) and the fourth branch node (34) are respectively located at the midpoints of two relatively narrow sides on the metal conduction band ring, and the length of the branch node is one eighth of the working wavelength; the first branch node (31) and the third branch node (33) are respectively located at two quarter points of the same long side of the metal conduction band ring, and the length of the branch node is one eighth of the working wavelength.

5. The miniaturized sum-difference network based on substrate integrated coaxial line according to claim 4, characterized in that: The diameter of the metallized via hole array around the first metal conductive strip (201) is 0.12 mm, the via hole spacing is 0.9 mm, and the distance between the via hole center and the microstrip centerline is 1.3 mm.

6. The miniaturized sum-difference network based on substrate-integrated coaxial line according to claim 5, characterized in that: There are vertical signal transmission vias (203) on the second branch (32) and the fourth branch (34), with a diameter of 0.824 mm and a height of 1.153 mm.

7. The miniaturized sum-difference network based on substrate integrated coaxial line according to claim 1, characterized in that: The length of the substrate integrated coaxial line used for connection is 15.788 mm. The connection line has two different shapes, namely a straight line type and a bent type. Each section of the transmission line connects the vertical signal transmission vias (203) of two couplers to each other.

8. The miniaturized sum-difference network based on substrate integrated coaxial line according to claim 1, characterized in that: The sum and difference network has 8 ports in total, port 1 to port 4 are signal input ports, and port 5 to port 8 are signal output ports.

9. The miniaturized sum-difference network based on substrate integrated coaxial line according to claim 1, characterized in that: The first metal layer (101), the second metal layer (105), the third metal layer (107) and the fourth metal layer (111) are made of copper with a thickness of 0.036 mm.

10. The miniaturized sum-difference network based on substrate integrated coaxial line according to claim 1, characterized in that: The first dielectric layer (102), the second dielectric layer (104), the third dielectric layer (108), and the fourth dielectric layer (110) are made of Rogers 4350 dielectric plates with a relative dielectric constant of 3.55 and a thickness of 0.508 mm; the first bonding layer (103), the adhesive layer (106), and the second bonding layer (109) are made of RO4450F dielectric plates with a relative dielectric constant of 3.52 and a thickness of 0.101 mm.

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