Dual-band broadband anti-phase filtering power divider

Abstract

This invention provides a dual-pass wideband inverting filter power divider, comprising an input port matching line, two sets of three-port short-circuit coupling line structures, a quarter-wavelength short-circuit line, two sets of half-wavelength short-circuit lines, a half-wavelength connecting line, an isolation network, and two output ports. During operation, the signal is input through the input terminal of the input port matching line, output to the first output port through the coupling terminal of the first three-port short-circuit coupling line structure, and connected to the second three-port short-circuit coupling line structure through the straight-through terminal of the first three-port short-circuit coupling line structure, outputting to the second output port through the coupling terminal of the second three-port short-circuit coupling line structure. The quarter-wavelength short-circuit line loaded at the straight-through terminal of the second three-port short-circuit coupling line structure can induce two transmission zeros, while the first half-wavelength short-circuit line and the second half-wavelength short-circuit line connected at the first and second output ports can generate one transmission zero, forming a dual-pass wideband filtering response. The isolation network achieves high-level isolation between the two output ports.

Description

Technical fields:

[0001] This invention belongs to the field of microwave passive device technology, specifically relating to a dual-pass wideband inverting filter power divider. Background technology:

[0002] With the continuous development of modern communication technology, single-function passive microwave devices can no longer meet the growing demand for multifunctional, miniaturized, and high-performance devices in radio frequency communication systems. More and more communication systems and functions are integrated onto a single communication terminal, leading to increasingly limited usable area in the radio frequency front-end circuit. To improve the utilization rate of equipment platforms, miniaturized circuits with integrated functions and multiple communication bands are highly favored. Among them, the inverting filter power divider, due to its integration of filtering, equal-amplitude inverting power distribution, and port isolation characteristics, is widely used in systems such as differential amplifiers, array antenna feed networks, and differential mixers, and has received extensive research attention. To meet the needs of multi-frequency communication systems, the implementation of high-performance dual-passband inverting filters has become one of the hot research topics.

[0003] Reference 1 (W.Yu,L.Xu,XYZhang and J.-X.Chen, "Dual-Band Dual-Mode Dielectric Resonator Filtering Power Divider With Flexible Output Phase Difference and Power Split Ratio," in IEEE Transactions on Microwave Theory and Techniques, vol.70, no.1, pp.190-199, Jan.2022.) utilizes the multimode resonance characteristics of hexagonal dielectric resonators to implement two dual-passband inverting filter power dividers with high out-of-band suppression. However, the three-dimensional size of the dielectric resonator is relatively large, which is not conducive to the miniaturization of planar circuit systems. In addition, the inverting filter power divider in this reference does not consider the design of output port isolation response, which can easily lead to signal crosstalk and port impedance mismatch between multiple connected devices.

[0004] Reference 2 (AM Zaidi, MTBeg, BK Kanaujia, Mainuddin and K. Rambabu, "A Compact Dual-Band Out of Phase Power Divider Having Microstrip Compatibility," in IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 67, no. 12, pp. 2998-3002, Dec. 2020.) designed a dual-passband inverting power divider using the phase characteristics of a dual-frequency quarter-wavelength transmission line and a 180° transmission line. This design has a relatively compact structural layout, but it does not consider the integration of filtering performance, and filter cascading is still required in applications.

[0005] Reference 3 (W.Qin, J.-X.Chen, L.-H.Zhou, Z.-H.Bao, Q.Xue, “Dual-Band In- / Anti-Phase Filtering Power Dividers,” in Microwave and Optical Technology Letters, vol.58, no.11, pp.2537-2786, Nov.2016.) utilizes the odd-even mode characteristics of stub-loaded resonators to design a dual-passband filter power divider with two passbands having different phase differences. However, this design method is difficult to achieve phase outputs with both passbands being out of phase, and the bandwidth of the dual-mode resonator is difficult to improve.

[0006] A review of published papers and findings reveals that existing dual-passband inverting power divider design techniques suffer from several drawbacks. While dielectric resonators can achieve good filter response integration and inverting power dividing characteristics, high-level isolation between output ports is difficult to achieve. Furthermore, the use of dielectric resonators typically results in larger device sizes. Although dual-passband inverting power dividers designed using dual-band quarter-wavelength transmission lines offer a compact size, they fail to integrate filtering functionality. Additionally, the design method using microstrip multimode resonators struggles to achieve wideband phase inversion. In other words, current dual-passband inverting power divider designs cannot simultaneously achieve compact size, good filter selectivity, large inverting bandwidth, and high output port isolation, hindering their widespread application in modern wireless communication systems. Summary of the Invention:

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing a dual-pass wideband inverting filter power divider.

[0008] The present invention adopts the following technical solution:

[0009] This invention provides a dual-pass wideband inverting filter power divider, comprising an input port matching line, a first three-port short-circuit coupling line structure, a second three-port short-circuit coupling line structure, a quarter-wavelength short-circuit line, a first half-wavelength short-circuit line, a second half-wavelength short-circuit line, a half-wavelength connecting line, an isolation network, a first output port, and a second output port; the first three-port short-circuit coupling line structure includes a first straight-through coupling line and a first short-circuit coupling line, and the second three-port short-circuit coupling line structure includes a second straight-through coupling line and a second short-circuit coupling line; the input end of the first straight-through coupling line is connected to the output end of the input port matching line, and the output end is connected to the second straight-through coupling line. The input terminals of the combined line are connected. One end of the first short-circuit coupling line is short-circuited, and the other end is connected to the first output port. The output terminal of the second straight-through coupling line is connected to the input terminal of the quarter-wavelength short line, and the terminal of the quarter-wavelength short line is short-circuited. One end of the second short-circuit coupling line is short-circuited, and the other end is connected to the second output port. The terminal of the first half-wavelength short line is short-circuited, and the other end is connected to the first output port. The terminal of the second half-wavelength short line is short-circuited, and the other end is connected to the second output port. The two ends of the half-wavelength connecting line are respectively connected to the first output port and the second output port. The isolation network is connected at the center point of the half-wavelength connecting line.

[0010] Furthermore, the signal is input through the input port of the matching line, output to the first output port through the coupling end of the first three-port short-circuited coupling line structure, and connected to the second three-port short-circuited coupling line structure through the straight-through end of the first three-port short-circuited coupling line structure. The signal is output to the second output port through the coupling end of the second three-port short-circuited coupling line structure. The different phases of the ports on both sides of the coupling line generate equal amplitude and opposite phase output signals, achieving equal power distribution with opposite phases. In addition, the quarter-wavelength short-circuit line connected to the straight-through end of the second three-port short-circuited coupling line structure can generate two transmission zeros, and the first half-wavelength short-circuit line and the second half-wavelength short-circuit line connected at the first and second output ports can generate one transmission zero, thus forming a dual-pass wideband filtering response. Finally, the isolation network connected to the output end through the half-wavelength connection line achieves a high level of isolation between the first and second output ports.

[0011] To optimize the above technical solution, the specific measures also include:

[0012] Furthermore, the isolation network includes a third half-wavelength short circuit and a grounding isolation resistor; the third half-wavelength short circuit is short-circuited at one end and connected to the grounding isolation resistor at the other end; the connection point between the third half-wavelength short circuit and the isolation resistor is located at the center point of the half-wavelength connection line.

[0013] Furthermore, the input port matching line includes an input port and an impedance matching line. The input port is located at one end of the impedance matching line and is composed of a 50Ω microstrip line and a 50Ω stripline connected together. The other end of the impedance matching line is connected to the input end of the first through coupling line.

[0014] Furthermore, both the first three-port short-circuit coupled line structure and the second three-port short-circuit coupled line structure are parallel coupled transmission line structures; the short-circuit end of the first short-circuit coupled line is close to the input end of the first straight-through coupled line; the short-circuit end of the second short-circuit coupled line is close to the output end of the second straight-through coupled line.

[0015] Furthermore, the first output port and the second output port are each composed of a 50Ω microstrip line.

[0016] Furthermore, the input port matching line, quarter-wavelength short line, first half-wavelength short line, second half-wavelength short line, half-wavelength connecting line, and third half-wavelength short line are all planar microwave transmission lines with certain characteristic impedances.

[0017] Furthermore, the present invention also comprises a first substrate, a second substrate, a third substrate, a fourth substrate, a fifth substrate, a sixth substrate, a seventh substrate, and an eighth substrate arranged sequentially from top to bottom; an isolation network is disposed on the upper surface of the first substrate, and a first metal ground plane is disposed on the lower surface; a first half-wavelength shorting line, a second half-wavelength shorting line, a half-wavelength connecting line, a first output port, and a second output port are disposed on the upper surface of the third substrate, and a second metal ground plane is disposed on the lower surface of the third substrate; a first short-circuit coupling line and a second short-circuit coupling line are disposed on the lower surface of the fourth substrate; a first through coupling line and a second through coupling line are disposed on the upper surface of the sixth substrate; a third metal ground plane is disposed on the upper surface of the seventh substrate, and an input port matching line and a quarter-wavelength shorting line are disposed on the lower surface of the seventh substrate; and a fourth metal ground plane is disposed on the lower surface of the eighth substrate.

[0018] Furthermore, the first substrate and the second substrate have rectangular slots formed at the 50Ω microstrip lines of the first output port and the second output port, exposing the 50Ω microstrip lines of the first output port and the second output port for connection with external circuits.

[0019] Furthermore, the eighth substrate has a rectangular groove at the 50Ω microstrip line of the input port, exposing the 50Ω microstrip line on the lower surface of the seventh substrate, which is connected to the external circuit.

[0020] Furthermore, the coupling strength of the first three-port short-circuit coupling line structure and the second three-port short-circuit coupling line structure determines the bandwidth of the dual-pass bandwidth inverting filter power divider. The greater the coupling strength, the greater the bandwidth of the dual-pass bandwidth inverting filter power divider.

[0021] Furthermore, in the input port matching line, the width of the impedance matching line is used to adjust the impedance matching within the two passbands.

[0022] Furthermore, the length and width of the quarter-wavelength short path control the position of the transmission zeros on both sides of the two filter passbands. The longer the length, the lower the frequency of the two transmission zeros; the wider the width, the closer the distance between the two transmission zeros.

[0023] Furthermore, the lengths of the first half-wavelength short line and the second half-wavelength short line determine the transmission zero position between the two passbands of the dual-pass wideband inverting filter power divider. The longer the length, the lower the frequency of the transmission zero, resulting in a smaller bandwidth of the low-frequency passband and a larger bandwidth of the high-frequency passband, which can be used to control the bandwidth ratio of the two passbands. The widths of the first half-wavelength short line and the second half-wavelength short line can control the impedance matching of the two passbands.

[0024] Furthermore, the grounding isolation resistor is used to absorb part of the signal reflected from the output port to achieve a certain degree of isolation between the output ports; the third half-wavelength short circuit is used to increase the number of zeros in the isolation response, thereby improving the isolation between the output ports. The length of the third half-wavelength short circuit is half the wavelength of the dual passband center frequency, and the width affects the isolation level. The smaller the width, the higher the isolation level.

[0025] The beneficial effects of this invention are:

[0026] Compared with existing technologies, this invention has the advantages of compact size, good filter selectivity, large inverting bandwidth, and high output port isolation, specifically manifested as follows:

[0027] (1) Compact size: The present invention adopts a transmission line structure, which can be realized by using a multi-layer dielectric stacked structure. The transmission line is easy to bend and can be miniaturized.

[0028] (2) Good filter selectivity: The present invention uses a stub resonator loading method to generate multiple transmission zeros, and both passband edges have steep frequency selectivity characteristics.

[0029] (3) Large anti-phase bandwidth: The present invention uses the anti-phase difference of short-circuit coupling line, which theoretically has the equal amplitude anti-phase characteristics of the whole frequency band.

[0030] (4) High output port isolation: The present invention adopts an isolation network design method that combines isolation resistors and transmission line resonators, and adds transmission zeros in the isolation response, which can improve the port isolation level of the inverting power divider in a wide frequency range. Attached image description:

[0031] Figure 1 This is a schematic diagram of the principle of the dual-pass wideband inverting filter power divider of the present invention;

[0032] Figure 2 This is a three-dimensional structural schematic diagram of the dual-pass wideband inverting filter power divider in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the planar structure of each layer of the dual-pass wideband inverting filter power divider in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the structural dimensions of the dual-pass wideband inverting filter power divider in an embodiment of the present invention;

[0035] Figure 5 This is a simulation curve of the S-parameters of the dual-pass wideband inverting filter power divider in an embodiment of the present invention;

[0036] Figure 6 This is a simulation curve of the amplitude difference and phase difference at the output port of the dual-pass wideband inverting filter power divider in an embodiment of the present invention;

[0037] The labels in the attached diagram are:

[0038] 1. Input port matching line; 11. Input port; 12. Impedance matching line; 2. First three-port short-circuit coupling line structure; 21. First straight-through coupling line; 22. First short-circuit coupling line; 3. Second three-port short-circuit coupling line structure; 31. Second straight-through coupling line; 32. Second short-circuit coupling line; 4. Quarter-wavelength short-circuit line; 5. First half-wavelength short-circuit line; 6. Second half-wavelength short-circuit line; 7. Half-wavelength connection line; 8. Isolation network; 81. Third half-wavelength short-circuit line; 82. Ground isolation resistor; 9. First output port; 10. Second output port;

[0039] 13. First substrate; 14. Second substrate; 15. Third substrate; 16. Fourth substrate; 17. Fifth substrate; 18. Sixth substrate; 19. Seventh substrate; 20. Eighth substrate;

[0040] 23. First metal grounding plate; 24. Second metal grounding plate; 25. Third metal grounding plate; 26. Fourth metal grounding plate. Detailed implementation method:

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0042] Example 1

[0043] This embodiment employs a combination of stripline, coupled stripline, and microstrip line methods to design a power divider, providing a dual-pass wideband anti-phase filter power divider with the following three-dimensional structure: Figure 2 As shown.

[0044] Specifically, refer to Figures 1-3 This structure includes an input port matching line 1, a first three-port short-circuit coupling line structure 2, a second three-port short-circuit coupling line structure 3, a quarter-wavelength short-circuit line 4, a first half-wavelength short-circuit line 5, a second half-wavelength short-circuit line 6, a half-wavelength connection line 7, an isolation network 8, a first output port 9 and a second output port 10, and a first substrate, a second substrate, a third substrate, a fourth substrate, a fifth substrate, a sixth substrate, a seventh substrate and an eighth substrate distributed from top to bottom. All eight substrates are PCB boards.

[0045] The first three-port short-circuit coupling line structure 2 includes a first straight-through coupling line 21 and a first short-circuit coupling line 22, and the second three-port short-circuit coupling line structure 3 includes a second straight-through coupling line 31 and a second short-circuit coupling line 32.

[0046] The first substrate has an isolation network 8 on its upper surface and a first metal ground plane on its lower surface; the second substrate has empty upper and lower surfaces; the third substrate has a first half-wavelength shorting line 5, a second half-wavelength shorting line 6, a half-wavelength connecting line 7, a first output port 9, and a second output port 10 on its upper surface and a second metal ground plane on its lower surface; the fourth substrate has a first short-circuit coupling line 22 and a second short-circuit coupling line 32 on its lower surface; the fifth substrate has empty upper and lower surfaces; the sixth substrate has a first straight-through coupling line 21 and a second straight-through coupling line 31 on its upper surface; the seventh substrate has a third metal ground plane on its upper surface and an input port matching line 1 and a quarter-wavelength shorting line 4 on its lower surface; the eighth substrate has a fourth metal ground plane on its lower surface.

[0047] The input port matching line 1 includes an input port 11 and an impedance matching line 12. The input port 11 is located at one end of the impedance matching line 12 and is composed of a 50Ω microstrip line and a 50Ω stripline. The other end of the impedance matching line 12 is connected to the input end of the first through coupling line 21 through a metallized via that passes through the third metal ground plane.

[0048] The input end of the first through coupling line 21 is connected to the output end of the input port matching line 1, and the output end is directly connected to the input end of the second through coupling line 31. One end of the first short-circuit coupling line 22 is connected to the second metal ground plane through a metallized via to form a short-circuit end. The short-circuit end of the first short-circuit coupling line 22 is close to the input end of the first through coupling line 21. The output end of the first short-circuit coupling line 22 is connected to the first output port 9 through a metallized via that penetrates the second metal ground plane.

[0049] The input end of the second through coupling line 31 is directly connected to the output end of the first through coupling line 21. The output end of the second through coupling line 31 is connected to the input end of the quarter-wavelength shorting line 4 through a metallized via through the third metal ground plane. The end of the quarter-wavelength shorting line 4 is connected to the third metal ground plane through a metallized via to form a short-circuit end. One end of the second short-circuit coupling line 32 is connected to the second metal ground plane through a metallized via to form a short-circuit end. The short-circuit end of the second short-circuit coupling line 32 is close to the output end of the second through coupling line 31. The output end of the second short-circuit coupling line 32 is connected to the second output port 10 through a metallized via through the second metal ground plane.

[0050] The first half-wavelength shorting line 5 is connected to the second metal ground plane via a metallized via to form a short circuit, and its other end is directly connected to the first output port 9. The second half-wavelength shorting line 6 is connected to the second metal ground plane via a metallized via to form a short circuit, and its other end is connected to the second output port 10. The two ends of the half-wavelength connecting line 7 are directly connected to the first output port 9 and the second output port 10, respectively.

[0051] The isolation network 8 includes a third half-wavelength short circuit 81 and a ground isolation resistor 82. The third half-wavelength short circuit 81 is short-circuited at one end and directly connected to the ground isolation resistor 82 at the other end. The connection point of the two is connected to the center point of the half-wavelength connection line 7 through a metallized via through the first metal ground plane.

[0052] In this embodiment, the first, second, and third metal ground planes are designed to avoid connection with through-hole metallized vias by using a slotting method. The first output port 9 and the second output port 10 are respectively constructed by connecting a 50Ω microstrip line and a 50Ω stripline.

[0053] The first substrate and the second substrate have rectangular slots at the 50Ω microstrip lines of the first output port 9 and the second output port 10, exposing the 50Ω microstrip lines of the first output port 9 and the second output port 10, so as to facilitate connection with external circuits; the eighth substrate has a rectangular slot at the 50Ω microstrip line of the input port 11, exposing the 50Ω microstrip line on the lower surface of the seventh substrate, so as to facilitate connection with external circuits.

[0054] The impedance matching line 12, quarter-wavelength shorting line 4, first half-wavelength shorting line 5, second half-wavelength shorting line 6, half-wavelength connecting line 7, and third half-wavelength shorting line 81 are each a stripline with a certain width. The first three-port short-circuit coupling line structure 2 and the second three-port short-circuit coupling line structure 3 are wide-side coupling stripline structures.

[0055] In the dual-pass wideband inverting power divider proposed in this invention, the width of the input port matching line 1 can be used to adjust the impedance matching within the two passbands; the coupling strength of the first three-port short-circuit coupling line structure 2 and the second three-port short-circuit coupling line structure 3 determines the bandwidth of the inverting power divider; the greater the coupling strength, the greater the bandwidth of the dual-pass wideband inverting power divider; the length and width of the quarter-wavelength short line 4 control the position of the transmission zeros on both sides of the two filter passbands; the longer the length, the lower the frequency of the two transmission zeros; the larger the width, the closer the distance between the two transmission zeros; the length of the first half-wavelength short line 5 and the second half-wavelength short line 6 determines the position of the transmission zeros between the two passbands of the dual-pass wideband inverting power divider; the longer the length, the lower the frequency of the transmission zeros, resulting in a smaller bandwidth of the low-frequency passband and a larger bandwidth of the high-frequency passband, which can be used to control the bandwidth ratio of the two passbands. The widths of the first half-wavelength shorting line 5 and the second half-wavelength shorting line 6 can control the impedance matching of the two passbands; the grounding isolation resistor 82 is used to absorb part of the signal reflected from the output port to achieve a certain degree of isolation between the output ports; the third half-wavelength shorting line 81 is used to increase the number of zeros in the isolation response, thereby improving the isolation between the output ports. The length of the third half-wavelength shorting line 81 is approximately half the wavelength of the center frequency of the dual passbands, and its width affects the isolation level. The smaller the width, the higher the isolation level.

[0056] Example 2

[0057] This embodiment describes the working mechanism of the dual-pass wideband inverting filter power divider in Embodiment 1.

[0058] The specific working mechanism is as follows:

[0059] The signal is input through input port 11 of the input port matching line 1, output to the first output port 9 through the coupling end of the first three-port short-circuit coupling line structure 2, and connected to the second three-port short-circuit coupling line structure 3 through the straight-through end of the first three-port short-circuit coupling line structure 2. The signal is output to the second output port 10 through the coupling end of the second three-port short-circuit coupling line structure 3. The different phases of the ports on both sides of the coupling line generate equal amplitude and opposite phase output signals, realizing equal power distribution with opposite phases. In addition, the quarter-wavelength short line 4 connected to the straight-through end of the second three-port short-circuit coupling line structure 3 can generate two transmission zeros, and the first half-wavelength short line 5 and the second half-wavelength short line 6 connected to the first output port 9 and the second output port 10 can generate one transmission zero, thus forming a dual-pass wideband filtering response. Finally, the isolation network 8 connected to the output end through the half-wavelength connection line 7 achieves a high level of isolation between the first output port 9 and the second output port 10.

[0060] Example 2

[0061] This embodiment limits the size parameters of the dual-pass wideband inverting filter power divider in Embodiment 1.

[0062] In this embodiment, the relative permittivity of the 8-layer substrate is 2.55, and the loss tangent is 0.001. The thickness of the first, second, third, seventh, and eighth substrates is 0.52 mm, the thickness of the fourth and sixth substrates is 0.26 mm, and the thickness of the fifth substrate is 0.13 mm.

[0063] Combination Figure 4 The dimensions of the inverting filter power divider are as follows: L p1 =3mm, W p1 =1.35mm, L f1 =2mm, W f1 =0.32mm, L p2 =3mm, W p2 =1.35mm, L f2 =1.8mm, W f2 =0.32mm, L1=15mm, W1=1.5mm, L2=L3=19.7mm, W2=W3=0.4mm, L 23 =44.3mm, W pad =0.5mm, W d =0.5mm, W ps =0.8mm, L5=L6=48.1mm, W5=W6=0.1mm, L7=25.15mm, W7=0.1mm, L8=51.1mm, W8=0.1mm, L gd =3mm, W gd =5mm, R=75Ω, the radius of the metallized via is 0.15mm. The total dimensions of the inverting filter power divider, including the 50Ω microstrip line conductor, are 24.375×23.2×3.53mm. 3 The corresponding guide wavelength dimension is approximately 0.2λ. g ×0.19λ g ×0.03λ g , where λ g The center frequency f of the first passband 01 =1.55GHz corresponds to the wavelength of the stripline guide.

[0064] The dual-passband inverting filter power divider in this embodiment was modeled and simulated in the electromagnetic simulation software ANSYS EM Suite 21.1. Figure 5 This is a simulation diagram of the S-parameters of the dual-passband inverting filter power divider in this embodiment. Figure 6 This is a simulation diagram of the amplitude difference and phase difference at the output port of the dual-passband inverting filter power divider in this embodiment. Figures 5-6As can be seen, the center frequencies of the two passbands of this dual-passband inverting filter power divider are 1.55GHz and 2.65GHz, respectively. The return loss within the passband is less than -20dB, the 3-dB relative bandwidth is 40.6% and 29%, respectively, the minimum insertion loss is 0.28(+3)dB and 0.35(+3)dB, respectively, the port isolation within the passband is 24.5dB and 21dB, respectively, the amplitude difference is within ±0.13dB and ±0.25dB, respectively, and the phase difference is between 180°±2°.

[0065] This invention utilizes printed circuit board manufacturing processes to process and etch the metal surfaces of the circuit board substrate to form the desired metal pattern. Metallized vias are achieved through a copper plating process. An eight-layer PCB board is connected to the metal ground planes of each layer via the metallized vias around its perimeter and assembled using metal screws. This results in low production costs and a compact structure. Simultaneously, a short-circuit coupling line structure and a wide-side coupling stripline are used to achieve inverting power division, providing a wide inverting bandwidth. A stub-loaded resonator generates transmission zeros, offering greater flexibility in passband structure design and high filter selectivity. Furthermore, this invention employs an isolation network design method combining isolation resistors and transmission line resonators, adding transmission zeros to the isolation response and improving the port isolation level of the inverting power divider over a wide bandwidth. Because this invention's dual-passband inverting filter power divider is compact, has good filter selectivity, a large inverting bandwidth, and high output port isolation, it is suitable for modern wireless communication systems.

[0066] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A dual-pass wideband inverting filter power divider, characterized in that, It includes an input port matching line (1), a first three-port short-circuit coupling line structure (2), a second three-port short-circuit coupling line structure (3), a quarter-wavelength short line (4), a first half-wavelength short line (5), a second half-wavelength short line (6), a half-wavelength connection line (7), an isolation network (8), a first output port (9), and a second output port (10). The first three-port short-circuit coupling line structure (2) includes a first straight-through coupling line (21) and a first short-circuit coupling line (22), and the second three-port short-circuit coupling line structure (3) includes a second straight-through coupling line (31) and a second short-circuit coupling line (32). The input end of the first through coupling line (21) is connected to the output end of the input port matching line (1), the output end of the first through coupling line (21) is connected to the input end of the second through coupling line (31), one end of the first short-circuit coupling line (22) is a short-circuit end, and the other end is connected to the first output port (9); the output end of the second through coupling line (31) is connected to the input end of the quarter-wavelength short line (4), and the terminal of the quarter-wavelength short line (4) is short-circuited; one end of the second short-circuit coupling line (32) is a short-circuit end, and the other end is connected to the second output port (10). The first half-wavelength short circuit (5) is short-circuited at one end, and the other end is connected to the first output port (9); The second half-wavelength short circuit (6) is short-circuited at one end, and the other end is connected to the second output port (10); One end of the half-wavelength connection line (7) is connected to the first output port (9), and the other end of the half-wavelength connection line (7) is connected to the second output port (10); the isolation network (8) is connected at the center point of the half-wavelength connection line (7).

2. The dual-pass wideband inverting filter power divider according to claim 1, characterized in that, The isolation network (8) includes a third half-wavelength short circuit (81) and a ground isolation resistor (82). The third half-wavelength short circuit (81) is short-circuited at one end and connected to the ground isolation resistor (82) at the other end. The connection point between the third half-wavelength short line (81) and the isolation resistor (82) is located at the center point of the half-wavelength connection line (7).

3. The dual-pass wideband inverting filter power divider according to claim 1, characterized in that, The input port matching line (1) includes an input port (11) and an impedance matching line (12). The input port (11) is located at one end of the impedance matching line (12) and is composed of a 50Ω microstrip line and a 50Ω strip line. The other end of the impedance matching line (12) is connected to the input end of the first through coupling line (21).

4. The dual-pass wideband inverting filter power divider according to claim 1, characterized in that, Both the first three-port short-circuit coupling line structure (2) and the second three-port short-circuit coupling line structure (3) are parallel coupling transmission line structures. The short-circuit end of the first short-circuit coupling line (22) is close to the input end of the first through coupling line (21); The short-circuit end of the second short-circuit coupling line (32) is close to the output end of the second through coupling line (31).

5. The dual-pass wideband inverting filter power divider according to claim 1, characterized in that, The first output port (9) and the second output port (10) are each composed of a 50Ω microstrip line.

6. The dual-pass wideband inverting filter power divider according to claim 2, characterized in that, The input port matching line (1), quarter-wavelength short line (4), first half-wavelength short line (5), second half-wavelength short line (6), half-wavelength connection line (7) and third half-wavelength short line (81) are all planar microwave transmission lines.

7. The dual-pass wideband inverting filter power divider according to claim 1, characterized in that, It also includes a first substrate, a second substrate, a third substrate, a fourth substrate, a fifth substrate, a sixth substrate, a seventh substrate, and an eighth substrate arranged sequentially from top to bottom; An isolation network (8) is provided on the upper surface of the first substrate, and a first metal ground plane is provided on the lower surface; The upper surface of the third substrate is provided with a first half-wavelength short circuit (5), a second half-wavelength short circuit (6), a half-wavelength connection line (7), a first output port (9), and a second output port (10), and the lower surface is provided with a second metal ground plane; The lower surface of the fourth substrate is provided with a first short-circuit coupling line (22) and a second short-circuit coupling line (32). The upper surface of the sixth substrate is provided with a first through coupling line (21) and a second through coupling line (31). The upper surface of the seventh substrate is provided with a third metal ground plane, and the lower surface is provided with an input port matching line (1) and a quarter-wavelength short line (4). The lower surface of the eighth substrate is provided with a fourth metal ground plane.

8. The dual-pass wideband inverting filter power divider according to claim 7, characterized in that, The first substrate and the second substrate have rectangular slots at the 50Ω microstrip lines of the first output port (9) and the second output port (10), exposing the 50Ω microstrip lines of the first output port (9) and the second output port (10) and connecting them to external circuits.

9. The dual-pass wideband inverting filter power divider according to claim 7, characterized in that, The eighth substrate has a rectangular groove at the 50Ω microstrip line of the input port (11), exposing the 50Ω microstrip line on the lower surface of the seventh substrate, which is connected to the external circuit.

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