Ultra-wideband sum-difference network and processing method

Abstract

The invention relates to the technical field of sum-difference networks, in particular to an ultra-wideband sum-difference network and a processing method. The filter comprises a metal lower cover plate, a dielectric plate assembly and a metal upper cover plate which are sequentially stacked from bottom to top, the dielectric plate assembly is internally provided with a first micro-band wiring and a second micro-band wiring, the two ends of the first micro-band wiring are connected with a sum input port and a first output branch port respectively, and the two ends of the second micro-band wiring are connected with a difference input port and a second output branch port respectively. And the first micro-strip wiring and the second micro-strip wiring are gradually staggered twice to form two sections of gradually-changing couplers which are connected in series with each other. The problem of engineering realization of an ultra-wide-band strong coupler and an ultra-wide-band large-angle phase shifter is solved, deterioration of indexes such as reflection coefficients, in-band fluctuation and port isolation caused by different phase velocities of odd and even modes and dielectric loss is reduced to the maximum extent in the 9-frequency-multiplication bandwidth, and good electrical performance is achieved.

Description

Technical Field

[0001] This invention relates to the field of sum-difference network technology, specifically to an ultra-wideband sum-difference network and its processing method. Background Technology

[0002] The sum-difference network is a key component of monopulse radar, forming a sum-difference beam by adding or subtracting received signals. It is a microwave four-port device with two input ports and two output ports. When the sum port is input, the two output ports have equal amplitude and phase, with the signal amplitude being half that of the input signal. When the difference port is input, the two output ports have equal amplitude and out-of-phase, with the output signal amplitude being half that of the input signal. A certain degree of isolation is maintained between the two output ports or the two input ports (sum and difference ports) to prevent interference.

[0003] Cascading a 3dB directional coupler and a 90-degree fixed phase shifter can create a microwave sum-difference network. In modern electronic warfare, the sum-difference beam network corresponding to the radar system needs to have broadband operating characteristics. To realize an ultra-wideband sum-difference network of 2-18GHz, ultra-wideband 3dB couplers and ultra-wideband phase shifters are required. Conventional waveguide magic T, branch bridge, ring bridge, multi-layer elliptical aperture coupler, and multi-section symmetrical coupler schemes cannot achieve a bandwidth of 9th harmonic, especially when strong coupling at 3dB. The even-mode impedance of multi-section couplers can reach up to about 300 ohms, and the coupling gap is very small, making it impractical in engineering.

[0004] To meet the requirements of compact structure, small size, and low profile, microstrip structure is the preferred choice. However, in microstrip lines, part of the electromagnetic field is in the dielectric and part is in the air, which causes the phase velocities of odd and even modes to be inconsistent during signal transmission. The even-mode signal transmitted in the dielectric is much slower than the odd-mode signal transmitted on the microstrip line. When achieving ultra-wideband, this will worsen parameters such as in-band reflection coefficient and in-band ripple. In addition, to achieve 3dB strong coupling, the distance between the two coupling lines may be less than 0.1mm, which is almost impossible to achieve in engineering. Therefore, this problem urgently needs to be solved. Summary of the Invention

[0005] To avoid and overcome the technical problems existing in the prior art, this invention provides an ultra-wideband sum-difference network and its processing method, which solves the engineering implementation problems of ultra-wideband strong couplers and ultra-wideband large-angle phase shifters. Within a bandwidth of 9 times the frequency, it minimizes the deterioration of indicators such as reflection coefficient, in-band ripple, and port isolation caused by the difference in phase velocity between odd and even modes and dielectric loss, thereby achieving better electrical performance.

[0006] To achieve the above objectives, the present invention provides the following technical solution: An ultra-wideband sum-difference network includes a metal lower cover plate, a dielectric substrate assembly, and a metal upper cover plate stacked sequentially from bottom to top. The dielectric substrate assembly has a first micro-strip line and a second micro-strip line. The two ends of the first micro-strip line are connected to an input port and a first output port, respectively. The two ends of the second micro-strip line are connected to a differential input port and a second output port, respectively. The first micro-strip line and the second micro-strip line are alternately stepped twice to form two stepped couplers connected in series, and a sawtooth coupling line is provided at the strong coupling point. The strong coupling point of the first stepped coupler along the signal transmission direction is arranged adjacent to the input port, and a phase compensation section is provided at the rear section of the second micro-strip line.

[0007] As a further embodiment of the present invention: the sum input port and the difference input port are respectively located at both ends of the first sidewall of the dielectric substrate assembly. The first micro-wire has a first section of coupler oblique micro-wire that is inclined to the length direction of the first sidewall. The second micro-wire has a first section of coupler straight micro-wire that is arranged along the length direction of the first sidewall. The first section of coupler oblique micro-wire and the first section of coupler straight micro-wire together form a first section of gradient coupler. The strong coupling part of the first section of coupler oblique micro-wire is connected to the sum input port, and the weak coupling part of the first section of coupler straight micro-wire is connected to the difference input port. The first micro-wire also has a second-section coupler straight micro-wire distributed along the length direction of the first sidewall, and the second micro-wire also has a second-section coupler oblique micro-wire arranged inclined to the length direction of the first sidewall. The second-section coupler straight micro-wire and the second-section coupler oblique micro-wire together form a second-section gradient coupler. The weak coupling part of the second-section coupler straight micro-wire is connected to the first output port, and the strong coupling part of the second-section coupler oblique micro-wire is connected to the second output port through a phase compensation section. The first-section gradient coupler and the second-section gradient coupler form a series connection, and the two sections of gradient coupler are symmetrically distributed at 180°.

[0008] As a further embodiment of the present invention: the side of the dielectric plate assembly opposite to the first sidewall is the second sidewall, the first output port and the second output port are both located on the second sidewall, the first output port is arranged near the weak coupling part of the second section of the gradient coupler, and the second output port is arranged near the first output port.

[0009] As a further embodiment of the present invention: the dielectric plate assembly is provided with two small metal wedges whose tips point to the strong coupling points of the two tapered couplers respectively, and the dielectric plate assembly is also provided with two large metal wedges whose tips point to the weak coupling points of the two tapered couplers respectively; both the large metal wedges and the small metal wedges can be slidably adjusted along their own axial direction.

[0010] As a further embodiment of the present invention: the dielectric substrate assembly includes a lower dielectric substrate, an intermediate dielectric substrate, and an upper dielectric substrate stacked sequentially from bottom to top. The first micro-strip line is located on the upper surface of the lower dielectric substrate, and the second micro-strip line is located on the lower surface of the upper dielectric substrate. The thickness of the lower and upper dielectric substrates is 1 mm, and the thickness of the intermediate dielectric substrate is 0.25 mm. The dielectric substrate assembly uses a high-frequency board Rogers 5880 with a dielectric constant of 2.2.

[0011] As a further embodiment of the present invention: the upper surface of the upper dielectric substrate has a first grounding copper foil, and the lower surface of the lower dielectric substrate has a second grounding copper foil.

[0012] As a further embodiment of the present invention: the inner side surface of the metal upper cover plate or the metal lower cover plate is fixed with at least two positioning pins that penetrate and position the medium plate assembly.

[0013] As a further embodiment of the present invention: the upper metal cover plate and the lower metal cover plate are clamped together with screws to fix the medium plate assembly.

[0014] As a further aspect of the present invention: the coupling degree of the two tapered couplers is both -8.34dB, so that they are connected in series to form a strong coupling broadband coupling with a coupling degree of -3dB.

[0015] A processing method for ultra-wideband sum-difference networks includes the following steps: S1. The first micro-strip line and the second micro-strip line are placed on the upper surface of the lower dielectric substrate and the lower surface of the upper dielectric substrate respectively according to the predetermined positions. The copper foils on the two surfaces of the intermediate dielectric substrate, the upper surface of the lower dielectric substrate, and the lower surface of the upper dielectric substrate are etched. The second grounding copper foil on the lower surface of the lower dielectric substrate and the first grounding copper foil on the upper surface of the upper dielectric substrate are retained and plated with pure gold. S2. Position and stack the lower dielectric plate, the middle dielectric plate, the upper dielectric plate and the metal cover plate sequentially from bottom to top on the surface of the lower metal cover plate using positioning pins; S3. Screws are used to pass through the upper medium plate, middle medium plate and lower medium plate sequentially from the metal upper cover plate, and are then locked and fixed to the metal lower cover plate. S4. Install SMA connectors at the input port, differential input port, first output port, and second output port, and install the small metal wedge and the large metal wedge in the designated positions.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This application adopts a series connection of two graded couplers. On the one hand, the graded coupling form also ensures that the in-band reflection coefficient is as small as possible. On the other hand, the high coupling device is realized by two low coupling devices, which can reduce the requirements for materials and processing accuracy and is very beneficial to improving the yield of the fabrication.

[0017] Furthermore, since the analysis of directional couplers generally adopts the odd-even mode analysis method, this application adopts a two-section tapered coupler. On the one hand, this structure can achieve strong coupling, and on the other hand, the transmission mode of electromagnetic waves on the stripline is the TEM mode. The electric field distribution of the odd and even modes is basically in a uniform medium, and the phase velocity of the odd and even modes is more consistent, which effectively improves the characteristics of the coupler's standing wave and isolation at high frequencies.

[0018] Furthermore, by widening the bandwidth of the microstrip line and adding sawtooth coupling lines at the strong coupling points, the odd-mode phase velocity can be further reduced, and the isolation and standing wave ratio at the high-frequency end can be improved. In addition, after the two tapered couplers are cascaded, a phase compensation section is set at the rear of the second microstrip line to compensate for the phase, which can meet the 180° phase requirement of the broadband sum-difference network.

[0019] In summary, this application solves the engineering implementation challenges of ultra-wideband strong couplers and ultra-wideband large-angle phase shifters. Within a bandwidth of 9 times the frequency, it minimizes the deterioration of indicators such as reflection coefficient, in-band ripple, and port isolation caused by the difference in phase velocities between odd and even modes and dielectric loss, thereby achieving better electrical performance.

[0020] 2. The special layout of the first and second micro-wires ensures that the area of ​​the two-section gradient coupler is always located within a small, approximately rectangular region, further realizing the miniaturization and lightweight design of the device.

[0021] 3. Due to the different transmission phase velocities of odd and even modes of the coupled microstrip lines, with odd modes being faster than even modes, a sawtooth coupling line is added at the strong coupling position in the coupler optimization. Combined with the large and small metal wedges that can slide and adjust along their own axes at the strong and weak coupling points, the spacing between the microstrip lines at the strong and weak coupling points can be adjusted, thereby adjusting the standing wave ratio, isolation, and amplitude fluctuations at the high-frequency end.

[0022] 4. This application abandons the traditional method of multi-layer lamination of three-layer microstrip boards using heated prepreg sheets. Instead, it employs pin positioning and screw locking to achieve rapid and accurate assembly. On one hand, this effectively prevents cracks in the copper foil of the metallized holes on the dielectric substrate assembly caused by heat during the lamination process, thus affecting the device's grounding effect and consequently its electrical performance. On the other hand, this structural design allows for rapid installation and disassembly, significantly reducing processing risks and design costs compared to multi-layer lamination methods. It features a simpler process, higher reliability, higher yield, and avoids the impact of processing techniques on electrical performance. Furthermore, the device boasts a miniaturized and lightweight design, with a simple appearance, light weight, and high reliability. Its scale can be expanded according to mission requirements, and it offers good upgrade and maintenance capabilities. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a conventional sum-difference network.

[0024] Figure 2 This is a schematic diagram of the external three-dimensional structure of the present invention.

[0025] Figure 3 This is a schematic diagram of the internal three-dimensional structure of the present invention.

[0026] Figure 4 This is a schematic cross-sectional view of the interlaced strip lines of the present invention.

[0027] Figure 5 This is a simulation curve of the transmission characteristics of the first and second output ports when the input port is connected to the input port in this invention.

[0028] Figure 6 This is a VSWR simulation curve of the sum input port, difference input port, first output port and second output port in this invention.

[0029] Figure 7 This is a phase simulation curve diagram of an embodiment of the present invention.

[0030] Figure 8 This is a simulation curve of the isolation degree of the present invention.

[0031] Figures 2-4 In the middle section: 11. Metal upper cover plate; 12. Metal lower cover plate; 20. Dielectric board assembly; 21. Upper dielectric board; 22. Middle dielectric board; 23. Lower dielectric board; 31. First grounding copper foil; 32. Second grounding copper foil; 41. First micro-stripe line; 411. First coupler oblique micro-stripe line; 412. Second coupler straight micro-stripe line; 42. Second micro-stripe line; 421. First coupler straight micro-stripe line; 422. Second coupler oblique micro-stripe line; 423. Phase compensation section; 5. Sawtooth coupling line; 61. Small metal wedge; 62. Large metal wedge; 7. Positioning pin; P1. Sum input port; P2. Difference input port; P3. First output port; P4. Second output port. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] For ease of understanding, the specific structure and operation of the present invention will be further described below with reference to the accompanying drawings: The principles of most existing general sum and difference network units are as follows: Figure 1 As shown, a typical network has four ports. When the sum port (B) is the input, output ports C and D are two signals with equal amplitude and in phase. When the difference port (A) is the input, output ports C and D are two signals with equal amplitude and opposite phase. Ports A and B are isolated from each other. The sum-difference network unit mainly includes a coupler and a 90° phase shifter. The coupler itself has a 90° phase shift. After the coupler and the 90° phase shifter are cascaded, when a signal is input to the difference port (A), there is a 180° phase shift difference between the output ports C and D, meaning the two ports are out of phase.

[0034] The specific structure of this invention is as follows: Figure 2-4 As shown, its main structure includes a metal lower cover plate 12, a dielectric plate assembly 20 and a metal upper cover plate 11 stacked from bottom to top. The dielectric plate assembly 20 has a first micro-strip line 41 and a second micro-strip line 42. The two ends of the first micro-strip line 41 are respectively connected to the input port P1 and the first output port P3, and the two ends of the second micro-strip line 42 are respectively connected to the differential input port P2 and the second output port P4. The first micro-strip line 41 and the second micro-strip line 42 are alternately stepped twice to form two stepped couplers connected in series. Both stepped couplers have weak coupling points that are gradually separated and strong coupling points that are gradually close to each other. The strong coupling points have sawtooth coupling lines 5. The strong coupling points of the first stepped coupler are arranged near the input port P1 along the signal transmission direction. The rear section of the second micro-strip line 42 is provided with a phase compensation section 423 to compensate for the phase, so that when the signal is input from the sum input port P1 or the difference input port P2, the signal output from the first output port P3 and the second output port P4 has the same phase or has a phase difference.

[0035] In practical implementation, the gradients of the two gradient couplers mentioned above are both fitted with the Klopfenstein gradient line function, resulting in a smooth structural transition without abrupt changes. This allows for a significant improvement in both directivity and standing wave ratio while widening the bandwidth.

[0036] Taking an ultra-wideband coupler in the 2-18 GHz range as an example, to achieve equal energy distribution in the sum-difference network, it is assumed that the coupler must achieve strong coupling of -3 dB. This application adopts a two-stage tapered coupler approach. On the one hand, the tapered coupling form also ensures that the in-band reflection coefficient is as small as possible; on the other hand, two-stage -8.34 dB couplers can be cascaded to form a strong coupling broadband coupling of -3 dB in series. That is, a high coupling device is achieved using two stages of low coupling devices, which can reduce the requirements for materials and processing precision and is very beneficial to improving the yield of the fabrication.

[0037] Since the analysis of directional couplers generally employs the even-odd mode analysis method, this application uses a two-section tapered coupler. This is because this structure enables strong coupling, and because the electromagnetic wave propagation mode on the stripline is the TEM mode, the electric field distribution of the even and odd modes is essentially within a homogeneous medium, resulting in more consistent phase velocities and effectively improving the coupler's standing wave ratio and isolation characteristics at high frequencies. Furthermore, by widening the microstrip line and adding a sawtooth coupling line 5 at the strong coupling point, the odd-mode phase velocity can be further reduced, improving isolation and standing wave ratio at high frequencies. Additionally, after cascading the two tapered couplers, this application includes a phase compensation section 423 at the rear of the second microstrip line 42, which meets the 180° phase requirement of broadband sum-difference networks.

[0038] In summary, this application solves the engineering implementation challenges of ultra-wideband strong couplers and ultra-wideband large-angle phase shifters. Within a bandwidth of 9 times the frequency, it minimizes the deterioration of indicators such as reflection coefficient, in-band ripple, and port isolation caused by the difference in phase velocities between odd and even modes and dielectric loss, thereby achieving better electrical performance.

[0039] Based on the above, such as Figure 3 As shown, the specific layout of the first micro-trace line 41 and the second micro-trace line 42 is as follows: like Figure 3 As shown, the sum input port P1 and the difference input port P2 are located at the two ends of the first sidewall of the dielectric substrate assembly 20, respectively. The first micro-wire line 41 has a first-section coupler oblique micro-wire line 411 that is inclined to the length direction of the first sidewall, and the second micro-wire line 42 has a first-section coupler straight micro-wire line 421 that is arranged along the length direction of the first sidewall. The first-section coupler oblique micro-wire line 411 and the first-section coupler straight micro-wire line 421 together form a first-section gradient coupler. The strong coupling part of the first-section coupler oblique micro-wire line 411 is connected to the sum input port P1, and the weak coupling part of the first-section coupler straight micro-wire line 421 is connected to the difference input port P2, thus constituting the layout of the first-section gradient coupler.

[0040] like Figure 3 As shown, the first micro-wire line 41 also has a second-section coupler straight micro-wire line 412 distributed along the length direction of the first sidewall, and the second micro-wire line 42 also has a second-section coupler oblique micro-wire line 422 inclined to the length direction of the first sidewall. The second-section coupler straight micro-wire line 412 and the second-section coupler oblique micro-wire line 422 together form a second-section gradient coupler. The weak coupling part of the second-section coupler straight micro-wire line 412 is connected to the first output port P3, and the strong coupling part of the second-section coupler oblique micro-wire line 422 is connected to the second output port P4 through the phase compensation section 423, thus constituting the layout of the second-section gradient coupler.

[0041] The first and second graded-change couplers together constitute the two graded-change couplers mentioned above.

[0042] Furthermore, such as Figure 3 As shown, the first and second graded couplers are connected end-to-end in series (specifically, the strong coupling points of the first and second graded couplers are the beginnings, and the weak coupling points are the ends, i.e., the beginning of the first graded coupler is connected to the end of the second graded coupler, and the end of the first graded coupler is connected to the beginning of the second graded coupler). Furthermore, from a perspective perpendicular to the dielectric substrate assembly 20, the two graded couplers are symmetrically distributed at 180° around a symmetrical point.

[0043] like Figure 3 As shown, the arrangement of the first micro-wire line 41 and the second micro-wire line 42 ensures that the area forming the two-section gradient coupler is always located within a small, approximately rectangular area, further realizing the miniaturization and lightweight design of the device.

[0044] Based on the above, such as Figure 3 As shown, the side of the dielectric substrate assembly 20 opposite to the first sidewall is designated as the second sidewall. Both the first output port P3 and the second output port P4 are located on the second sidewall. The first output port P3 is arranged near the weak coupling point of the second weakly tapered coupler, and the second output port P4 is arranged near the first output port P3. This layout facilitates the arrangement of the phase compensation section 423, further reducing its space occupation and thus achieving a more miniaturized and lightweight design. Specifically, the phase compensation section 423 can be an S-shaped bend or other shaped bends that can delay the signal transmission length, thereby achieving broadband phase shifting.

[0045] Based on the above, such as Figure 3 As shown, the dielectric substrate assembly 20 is provided with two small metal wedges 61, the tips of which respectively point to the strong coupling points of the two tapered couplers. The dielectric substrate assembly 20 is also provided with two large metal wedges 62, the tips of which respectively point to the coupling points of the two tapered couplers. In an embodiment where the sum input port P1 and the difference input port P2 are located on the first sidewall of the dielectric substrate assembly 20, and the first output port P3 and the second output port P4 are both located on the second sidewall, the large metal wedges 62 and the small metal wedges 61 are located at both ends of the dielectric substrate assembly 20. Furthermore, both the large metal wedges 62 and the small metal wedges 61 can be slidably adjusted along their own axial direction.

[0046] Due to the difference in the phase velocities of odd and even modes of the coupled microstrip lines, with odd modes being faster than even modes, a sawtooth coupling line 5 is added at the strong coupling point in the coupler optimization. This is combined with a large metal wedge 62 and a small metal wedge 61 that can be adjusted along their own axial direction at the strong and weak coupling points (specifically, the adjustment can be made by using a screw-like threaded connection commonly used in existing technologies, or by using a sliding damping adjustment method). This allows the spacing between the microstrip lines at the strong and weak coupling points to be adjusted, thereby adjusting the standing wave ratio, isolation, and amplitude fluctuations at the high-frequency end.

[0047] Based on the above, such as Figure 4 As shown, the dielectric substrate assembly 20 includes a lower dielectric substrate 23, an intermediate dielectric substrate 22, and an upper dielectric substrate 21 stacked sequentially from bottom to top. A first microstrip line 41 is located on the upper surface of the lower dielectric substrate 23, and a second microstrip line 42 is located on the lower surface of the upper dielectric substrate 21. The thickness of the lower dielectric substrate 23 and the upper dielectric substrate 21 is 1 mm, and the thickness of the intermediate dielectric substrate 22 is 0.25 mm. The dielectric substrate assembly 20 uses a high-frequency Rogers 5880 substrate with a dielectric constant of 2.2. Since the dielectric substrate assembly 20 generally selects microstrip line materials with small loss guide angles, this application preferably uses a high-frequency Rogers 5880 substrate with a loss guide angle of 0.0009. Because the dielectric thermal expansion coefficient of this substrate is larger than that of copper, heating can cause the microstrip line to break. Figure 1 and Figure 2 As shown, this application innovatively uses at least two positioning pins 7 on the inner side of the metal upper cover plate 11 or the metal lower cover plate 12 to penetrate and position the medium plate assembly 20. Then, the medium plate assembly 20 is clamped and fixed between the metal upper cover plate 11 and the metal lower cover plate 12 by screws. This avoids material deformation caused by high temperature hot pressing and also enables the rapid and accurate assembly of this application.

[0048] Based on the above, such as Figure 4 As shown, the upper surface of the upper dielectric substrate 21 has a first grounding copper foil 31, and the lower surface of the lower dielectric substrate 23 has a second grounding copper foil 32, which realizes grounding that affects the stability of the device and ensures the electrical performance of the device.

[0049] The above-mentioned processing method for ultra-wideband sum-difference networks includes the following steps: S1. The first micro-strip line 41 and the second micro-strip line 42 are placed on the upper surface of the lower dielectric substrate 23 and the lower surface of the upper dielectric substrate 21 respectively according to the predetermined positions. The copper foils on the two surfaces of the intermediate dielectric substrate 22, the upper surface of the lower dielectric substrate 23 and the lower surface of the upper dielectric substrate 21 are etched, and the second grounding copper foil 32 on the lower surface of the lower dielectric substrate 23 and the first grounding copper foil 31 on the upper surface of the upper dielectric substrate 21 are retained and plated with pure gold. S2. The lower dielectric plate 23, the middle dielectric plate 22, the upper dielectric plate 21 and the metal upper cover plate 11 are positioned and stacked on the upper surface of the metal lower cover plate 12 from bottom to top using the positioning pins 7. S3. The upper medium plate 21, the middle medium plate 22 and the lower medium plate 23 are sequentially passed through the metal upper cover plate 11 by screws, and are locked and fixed with the metal lower cover plate 12. S4. Install SMA connectors at the input port P1, the differential input port P2, the first output port P3, and the second output port P4, and install the small metal wedge 61 and the large metal wedge 62 in the designated positions.

[0050] This design abandons the traditional method of heating and prepreg to laminate three layers of microstrip board, effectively preventing heat-induced cracks in the copper foil of the metallized holes on the dielectric substrate assembly 20, which could affect the grounding effect and consequently the electrical performance of the device. Furthermore, this structural design allows for rapid installation and disassembly, significantly reducing processing risks and design costs compared to multilayer lamination methods. It features a simpler process, higher reliability, and higher yield, avoiding the impact of processing techniques on electrical performance. The device also boasts a miniaturized and lightweight design, with a simple appearance, light weight, and high reliability. Its scale can be expanded according to mission requirements, and it offers good upgrade and maintenance capabilities.

[0051] To verify the accuracy of the above scheme, the applicant conducted actual verification as follows: Figure 5-8 As shown: Figure 5 This is a simulation curve of the transmission characteristics of the first output port P3 and the second output port P4 when input is made through input port P1 in this invention. In the figure, the maximum in-band loss of S13 and S14 is 4.55dB. After removing the theoretical loss of 3dB, the insertion loss is ≤1.55dB and the in-band ripple is ≤2dB.

[0052] Figure 6 This is a simulation graph of the VSWR of the input port P1, the differential input port P2, the first output port P3, and the second output port P4 in this invention. The VSWR of each port is ≤1.82, and the maximum point is S11 at around 15.5GHz.

[0053] Figure 7 This is a phase simulation curve diagram of an embodiment of the present invention. When an input signal is input to input port P1, the first output port P3 and the second output port P4 are in phase, and from... Figure 6 As can be seen, the phase difference between S13 and S14 fluctuates within -9° to 5° in the 2-18GHz bandwidth. When a signal is input to the differential input port P2, the first output port P3 and the second output port P4 are out of phase. Figure 6As can be seen, the phase difference between S13 and S14 fluctuates within 168° to 189° in the 2-18GHz bandwidth, which meets the characteristic requirements.

[0054] Figure 8 The simulation curve of the isolation degree of the present invention shows that the sum and difference isolation S12 and the port isolation S34 are ≥-15dB in the 2-18GHz broadband range.

[0055] Clearly, the sum-difference network of this application can meet the requirements of this application for a 2-18GHz ultrawideband sum-difference network with strong coupling of 3dB, while widening the bandwidth and ensuring a small in-band reflection coefficient. At the same time, it also effectively improves the isolation and standing wave at the high-frequency end.

[0056] Of course, those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0057] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0058] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. An ultra-wideband sum-difference network, characterized in that, The device includes a metal lower cover plate (12), a dielectric substrate assembly (20), and a metal upper cover plate (11) stacked from bottom to top. The dielectric substrate assembly (20) has a first micro-strip line (41) and a second micro-strip line (42). The two ends of the first micro-strip line (41) are connected to the input port (P1) and the first output port (P3), respectively. The two ends of the second micro-strip line (42) are connected to the differential input port (P2) and the second output port (P4), respectively. The first micro-strip line (41) and the second micro-strip line (42) are interleaved twice to form two series-connected stepped couplers, and a sawtooth coupling line (5) is provided at the strong coupling point. The strong coupling point of the first stepped coupler along the signal transmission direction is arranged adjacent to the input port (P1), and a phase compensation section (423) is provided at the rear of the second micro-strip line (42).

2. The ultra-wideband sum-difference network according to claim 1, characterized in that, The sum input port (P1) and difference input port (P2) are located at both ends of the first sidewall of the dielectric substrate assembly (20). The first micro-wire (41) has a first section of coupler oblique micro-wire (411) arranged in an inclined direction along the length of the first sidewall. The second micro-wire (42) has a first section of coupler straight micro-wire (421) arranged along the length of the first sidewall. The first section of coupler oblique micro-wire (411) and the first section of coupler straight micro-wire (421) together form a first section of gradient coupler. The strong coupling point of the first section of coupler oblique micro-wire (411) is connected to the sum input port (P1), and the weak coupling point of the first section of coupler straight micro-wire (421) is connected to the difference input port (P2). The first micro-wire (41) also has a second-section coupler straight micro-wire (412) distributed along the length direction of the first sidewall, and the second micro-wire (42) also has a second-section coupler oblique micro-wire (422) inclined to the length direction of the first sidewall. The second-section coupler straight micro-wire (412) and the second-section coupler oblique micro-wire (422) together form a second-section gradient coupler. The weak coupling part of the second-section coupler straight micro-wire (412) is connected to the first output port (P3), and the strong coupling part of the second-section coupler oblique micro-wire (422) is connected to the second output port (P4) through the phase compensation section (423). The first-section gradient coupler and the second-section gradient coupler form a series connection, and the two sections of gradient coupler are symmetrically distributed at 180° around a symmetrical point.

3. The ultra-wideband sum-difference network according to claim 2, characterized in that, The second sidewall is the side of the dielectric substrate assembly (20) that is opposite to the first sidewall. The first output port (P3) and the second output port (P4) are both located on the second sidewall. The first output port (P3) is arranged near the weak coupling point of the second weak gradient coupler, and the second output port (P4) is arranged near the first output port (P3).

4. An ultra-wideband sum-difference network according to claim 1, 2, or 3, characterized in that, The dielectric plate assembly (20) is provided with two small metal wedges (61) whose tips point to the strong coupling points of the two tapered couplers respectively, and the dielectric plate assembly (20) is also provided with two large metal wedges (62) whose tips point to the weak coupling points of the two tapered couplers respectively; both the large metal wedges (62) and the small metal wedges (61) can be slidably adjusted along their own axial direction.

5. An ultra-wideband sum-difference network according to claim 1, 2, or 3, characterized in that, The dielectric substrate assembly (20) includes a lower dielectric substrate (23), an intermediate dielectric substrate (22) and an upper dielectric substrate (21) stacked from bottom to top. The first micro-strip line (41) is located on the upper surface of the lower dielectric substrate (23) and the second micro-strip line (42) is located on the lower surface of the upper dielectric substrate (21). The thickness of the lower dielectric substrate (23) and the upper dielectric substrate (21) is 1 mm, and the thickness of the intermediate dielectric substrate (22) is 0.25 mm. The dielectric substrate assembly (20) uses a high-frequency board Rogers5880 with a dielectric constant of 2.

2.

6. The ultra-wideband sum-difference network according to claim 5, characterized in that, The upper surface of the upper dielectric substrate (21) has a first grounded copper foil (31), and the lower surface of the lower dielectric substrate (23) has a second grounded copper foil (32).

7. The ultra-wideband sum-difference network according to claim 5, characterized in that, The inner side of the metal upper cover plate (11) or metal lower cover plate (12) is fixed with at least two positioning pins (7) that penetrate and position the medium plate assembly (20).

8. The ultra-wideband sum-difference network according to claim 7, characterized in that, The media plate assembly (20) is fixed between the upper metal cover plate (11) and the lower metal cover plate (12) by screws.

9. An ultra-wideband sum-difference network according to claim 1, 2, or 3, characterized in that, The two tapered couplers each have a coupling degree of -8.34dB, and are connected in series to form a strong-coupled broadband coupling with a coupling degree of -3dB.

10. A processing method for ultra-wideband sum-difference networks, characterized in that, Includes the following steps: S1. The first micro-strip line (41) and the second micro-strip line (42) are placed on the upper surface of the lower dielectric substrate (23) and the lower surface of the upper dielectric substrate (21) respectively according to the predetermined positions. The copper foils on the two surfaces of the intermediate dielectric substrate (22), the upper surface of the lower dielectric substrate (23) and the lower surface of the upper dielectric substrate (21) are etched, and the second grounding copper foil (32) on the lower surface of the lower dielectric substrate (23) and the first grounding copper foil (31) on the upper surface of the upper dielectric substrate (21) are retained and plated with pure gold. S2. The lower dielectric plate (23), the middle dielectric plate (22), the upper dielectric plate (21) and the metal upper cover plate (11) are positioned and stacked on the upper surface of the metal lower cover plate (12) from bottom to top using positioning pins (7); S3. Through screws, the upper medium plate (21), the middle medium plate (22), and the lower medium plate (23) are sequentially passed through the metal upper cover plate (11) and locked to the metal lower cover plate (12); S4. Install SMA connectors at the input port (P1), the input port (P2), the first output port (P3), and the second output port (P4), and install the small metal wedge (61) and the large metal wedge (62) in the designated positions.

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