A balanced-unbalanced power divider with broadband non-reflection filtering characteristics

Abstract

The present invention discloses a balanced-unbalanced power divider with broadband non-reflection filtering characteristics, comprising: a balanced differential signal input port A, two unbalanced end signal output ports, two non-reflection filtering power division networks, two sections of quarter-wavelength anti-connected wiring, two sections of quarter-wavelength signal transmission lines and an isolation network. The device realizes highly selective filtering characteristics, conversion function from balanced differential signals to unbalanced single-ended signals, good common-mode suppression, two-way broadband equal power distribution, 180-degree output signal phase difference characteristics, and both the balanced end and the unbalanced single end have broadband non-reflection filtering characteristics. The device is very suitable for application in various balanced-unbalanced microwave systems to improve their overall performance.

Description

Technical Field

[0001] The invention relates to a filtering power divider, in particular to a balanced-unbalanced power divider with broadband non-reflection filtering characteristics. Background Art

[0002] Nowadays, microwave radio frequency wireless communication systems are developing towards miniaturization and integration, so the research on microwave functional fusion devices such as filter power dividers is of great practical value. In order to make filter power dividers more widely used in engineering, and to ensure the miniaturization advantage of filter power dividers, how to improve the isolation, frequency selectivity, out-of-band suppression and insertion loss of filter power dividers has become the main direction for researchers at home and abroad. Microstrip line is a transmission line with the advantages of miniaturization, low cost and stable performance. Therefore, as today's wireless communication systems develop towards miniaturization and integration, more and more scholars at home and abroad have begun to study filter power dividers with microstrip line structure. In addition, with the continuous improvement of information transmission rate, electromagnetic interference between circuits has become more and more serious. Balanced circuits have developed rapidly because of their strong immunity to environmental noise and electromagnetic interference. At present, various balanced components have been widely studied and applied. For systems with both balanced ports and unbalanced ports, it is very necessary to use balanced to unbalanced filter power dividers as connecting devices. Therefore, the research on new balanced-unbalanced bandpass filter power dividers with small size and high performance has scientific research and engineering significance. Normally, the signal entering the balanced end is transmitted to the unbalanced end after filtering, but the signal in the stopband is reflected back to its own balanced end, which will generate unnecessary interference to the balanced end signal and affect the overall stability of the system. In order to meet the robust operation of the entire RF system, the reflectionless filter power divider has attracted much attention in recent years. As we all know, the reflected signal of the traditional reflection filter power divider passes through sensitive nonlinear elements such as mixers and amplifiers, which will cause the deterioration of the working state of adjacent active devices. Unlike the traditional reflection filter power divider, the reflectionless filter power divider can absorb the out-of-band interference signal reflected back to the source end, and its out-of-band reflected energy can often be absorbed by loading a terminal load at the port, so it can effectively improve the signal-to-noise ratio and stability of the adjacent active circuit in the RF front-end system. However, the existing balanced-unbalanced reflectionless filter power divider is large in size and not all ports have achieved broadband reflectionless filtering characteristics. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention discloses a balanced-unbalanced power divider with broadband non-reflection filtering characteristics, comprising: a balanced differential signal input port A, two unbalanced end signal output ports, two non-reflection filtering power division networks, two quarter-wavelength anti-connected wirings, two quarter-wavelength signal transmission lines and an isolation network;

[0004] The balanced differential signal input port A includes an input port A+ and an input port A-;

[0005] The two unbalanced signal output ports include output port 2 and output port 3;

[0006] The two reflectionless filtering power division networks include a first reflectionless filtering power division network and a second reflectionless filtering power division network;

[0007] The two quarter-wavelength anti-connected wirings include a first anti-connected wiring and a second anti-connected wiring; wherein one end of the first anti-connected wiring is connected to the connection between the input port A+ and the first reflection-free filter power division network, and the other end is connected to the second anti-connected wiring; one end of the second anti-connected wiring is connected to the connection between the input port A- and the second reflection-free filter power division network, and the other end is connected to the first anti-connected wiring;

[0008] One end of the first reflectionless filter power division network is connected to the connection between the first anti-connected wiring and the input port A+, and the other end is connected to the first signal transmission line; one end of the second reflectionless filter power division network is connected to the connection between the second anti-connected wiring and the input port A-, and the other end is connected to the second signal transmission line;

[0009] The first non-reflection filtering power division network and the second non-reflection filtering power division network have the same structure; the first non-reflection filtering power division network comprises a first filtering power open circuit coupling line, a second filtering power open circuit coupling line, a first non-reflection absorbing transmission line, a second non-reflection absorbing transmission line, a first non-reflection absorbing open line, a second non-reflection absorbing open line, a first non-reflection absorbing resistor, a second non-reflection absorbing resistor and a non-reflection absorbing short circuit line;

[0010] The first port of the first filter power open circuit coupled line is connected to the input port A+, the second port is connected to the first non-reflection absorption transmission line, the third port is open circuit, and the fourth port is connected to the fourth port of the second filter power open circuit coupled line; the first port of the second filter power open circuit coupled line is connected to the first signal transmission line, the second port is connected to the second non-reflection absorption transmission line, the third port is open circuit, and the fourth port is connected to the fourth port of the first filter power open circuit coupled line; one end of the first non-reflection absorption transmission line is connected to the second port of the first filter power open circuit coupled line, and the other end is connected to the connection between the first non-reflection absorption open line and the first non-reflection absorption resistor; the second non-reflection One end of the reflection-absorbing transmission line is connected to the second port of the second filter power open circuit coupling line, and the other end is connected to the connection between the second reflection-free absorption open line and the second reflection-free absorption resistor; one end of the first reflection-free absorption resistor is connected to the connection between the first reflection-free absorption open line and the first reflection-free absorption transmission line, and the other end is connected to the connection between the reflection-free absorption short-circuit line and the second reflection-free absorption resistor; one end of the second reflection-free absorption resistor is connected to the connection between the second reflection-free absorption open line and the second reflection-free absorption transmission line, and the other end is connected to the connection between the reflection-free absorption short-circuit line and the first reflection-free absorption resistor; the reflection-free absorption short-circuit line is connected to the connection between the first reflection-free absorption resistor and the second reflection-free absorption resistor;

[0011] The two quarter-wavelength signal transmission lines include a first signal transmission line and a second signal transmission line; wherein one end of the first signal transmission line is connected to the first reflectionless filter power division network, and the other end is connected to the connection between the isolation network and the output port 2; one end of the second signal transmission line is connected to the second reflectionless filter power division network, and the other end is connected to the connection between the isolation network and the output port 3;

[0012] One end of the isolation network is connected to the connection between the first signal transmission line and the output port 2, and the other end is connected to the connection between the second signal transmission line and the output port 3;

[0013] The isolation network includes a first isolation resistor, a half-wavelength transmission line and a second isolation resistor; one end of the first isolation resistor is connected to the connection between the first signal transmission line and the output port two, and the other end is connected to the half-wavelength transmission line; one end of the half-wavelength transmission line is connected to the first isolation resistor, and the other end is connected to the second isolation resistor; one end of the second isolation resistor is connected to the half-wavelength transmission line, and the other end is connected to the connection between the second signal transmission line and the output port three.

[0014] The characteristic impedance of the non-reflective absorbing short-circuit is Z a , the characteristic impedances of the first non-reflection absorption transmission line and the second non-reflection absorption transmission line are both Z c, the resistance values ​​of the first non-reflection absorption resistor and the second non-reflection absorption resistor are both R2; by adjusting Z a , Z c and R2 to adjust the reflection-free characteristics of the balanced differential signal input port A and the unbalanced signal output port.

[0015] The filtering characteristics of the balanced-unbalanced power divider are improved by adjusting the first filtering power splitter circuit coupling line and the second filtering power splitter circuit coupling line.

[0016] The characteristic impedances of the first non-reflection absorbing open line and the second non-reflection absorbing open line are both Z b By adjusting Z b This adjusts the position of the transmission zeros on both sides of the passband.

[0017] The isolation characteristics of the two unbalanced signal output ports are improved by adjusting the isolation network.

[0018] Due to the adoption of the above technical scheme, the present invention provides a balanced-unbalanced power divider with broadband non-reflection filtering characteristics. In order to realize the conversion function from balanced differential signal to unbalanced single-ended signal, the reflection-free bandpass filtering power distribution under the excitation of balanced differential mode signal and the reflection-free filtering power synthesis function during unbalanced single-ended input, the present invention provides a balanced-unbalanced power divider with broadband non-reflection filtering characteristics. The power divider realizes the interconnection of balanced and unbalanced devices without using a balun. In addition, it also realizes two-way equal-power broadband output characteristics, 180-degree output signal phase difference characteristics, highly selective bandpass filtering characteristics, good common-mode suppression, balanced differential mode reflection-free bandpass filtering and other power distribution and reflection-free filtering power synthesis function during unbalanced single-ended input, which is very suitable for application in various balanced-unbalanced microwave systems to improve their overall performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a structural schematic diagram of a balanced-unbalanced power divider with broadband non-reflection filtering characteristics of the present invention;

[0021] Figure 2 It is a mixed S parameter curve diagram of a balanced-unbalanced power divider with broadband non-reflection filtering characteristics under differential mode signal excitation of the present invention;

[0022] Figure 3 It is a mixed S parameter curve diagram of a balanced-unbalanced power divider with broadband non-reflection filtering characteristics under common mode signal excitation of the present invention;

[0023] Figure 4 The output signal phase difference curve diagram of a balanced-unbalanced power divider with broadband non-reflection filtering characteristics of the present invention. DETAILED DESCRIPTION

[0024] In order to make the technical solutions and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention:

[0025] like Figure 1 A balanced-unbalanced power divider with broadband non-reflection filtering characteristics is shown, comprising: a balanced differential signal input port A, two unbalanced signal output ports, two non-reflection filtering power division networks, two quarter-wavelength anti-connected wirings, two quarter-wavelength signal transmission lines and an isolation network 11;

[0026] The balanced differential signal input port A includes an input port A+1 and an input port A-4;

[0027] The two unbalanced signal output ports include output port 2 and output port 3;

[0028] The two reflectionless filtering power division networks include a first reflectionless filtering power division network 7 and a second reflectionless filtering power division network 8;

[0029] The two quarter-wavelength anti-connected wirings include a first anti-connected wiring 5 and a second anti-connected wiring 6; wherein one end of the first anti-connected wiring 5 is connected to the connection between the input port A+1 and the first reflection-free filter power division network 7, and the other end is connected to the second anti-connected wiring 6; one end of the second anti-connected wiring 6 is connected to the connection between the input port A-4 and the second reflection-free filter power division network 8, and the other end is connected to the first anti-connected wiring 5;

[0030] One end of the first non-reflection filter power division network 7 is connected to the connection between the first anti-connection connection 5 and the input port A+1, and the other end is connected to the first signal transmission line 9; one end of the second non-reflection filter power division network 8 is connected to the connection between the second anti-connection connection 6 and the input port A-2, and the other end is connected to the second signal transmission line 10;

[0031] The first non-reflection filtering power division network 7 and the second non-reflection filtering power division network 8 have the same structure; the first non-reflection filtering power division network 7 comprises a first filtering power open circuit coupling line 70, a second filtering power open circuit coupling line 71, a first non-reflection absorbing transmission line 72, a second non-reflection absorbing transmission line 73, a first non-reflection absorbing open line 74, a second non-reflection absorbing open line 75, a first non-reflection absorbing resistor 76, a second non-reflection absorbing resistor 77 and a non-reflection absorbing short circuit line 78;

[0032] The first port 701 of the first filter power open circuit coupling line 70 is connected to the input port A+1, the second port 702 is connected to the first non-reflection absorption transmission line 72, the third port 703 is open, and the fourth port 704 is connected to the fourth port 714 of the second filter power open circuit coupling line 71; the first port 711 of the second filter power open circuit coupling line 71 is connected to the first signal transmission line 9, the second port 712 is connected to the second non-reflection absorption transmission line 73, the third port 713 is open, and the fourth port 714 is connected to the fourth port 704 of the first filter power open circuit coupling line 70; one end of the first non-reflection absorption transmission line 72 is connected to the second port 702 of the first filter power open circuit coupling line 70, and the other end is connected to the connection line between the first non-reflection absorption open line 74 and the first non-reflection absorption resistor 76. one end of the second non-reflection absorption transmission line 73 is connected to the second port 712 of the second filter power open circuit coupling line 71, and the other end is connected to the connection between the second non-reflection absorption open line 75 and the second non-reflection absorption resistor 77; one end of the first non-reflection absorption resistor 76 is connected to the connection between the first non-reflection absorption open line 74 and the first non-reflection absorption transmission line 72, and the other end is connected to the connection between the non-reflection absorption short-circuit line 78 and the second non-reflection absorption resistor 77; one end of the second non-reflection absorption resistor 77 is connected to the connection between the second non-reflection absorption open line 75 and the second non-reflection absorption transmission line 73, and the other end is connected to the connection between the non-reflection absorption short-circuit line 78 and the first non-reflection absorption resistor 76; the non-reflection absorption short-circuit line 78 is connected to the connection between the first non-reflection absorption resistor 76 and the second non-reflection absorption resistor 77;

[0033] The two quarter-wavelength signal transmission lines include a first signal transmission line 9 and a second signal transmission line 10; wherein one end of the first signal transmission line 9 is connected to the first reflectionless filter power division network 7, and the other end is connected to the connection between the isolation network 11 and the output port 2; one end of the second signal transmission line 10 is connected to the second reflectionless filter power division network 8, and the other end is connected to the connection between the isolation network 11 and the output port 3;

[0034] One end of the isolation network 11 is connected to the connection between the first signal transmission line 9 and the output port 2, and the other end is connected to the connection between the second signal transmission line 10 and the output port 3;

[0035] The isolation network 11 includes a first isolation resistor 111, a half-wavelength transmission line 112 and a second isolation resistor 112; one end of the first isolation resistor 111 is connected to the connection between the first signal transmission line 9 and the output port 2, and the other end is connected to the half-wavelength transmission line 112; one end of the half-wavelength transmission line 112 is connected to the first isolation resistor 111, and the other end is connected to the second isolation resistor 113; one end of the second isolation resistor 113 is connected to the half-wavelength transmission line 112, and the other end is connected to the connection between the second signal transmission line 10 and the output port 3;

[0036] The characteristic impedance of the non-reflective absorbing short-circuit line 78 is Z a , the characteristic impedances of the first non-reflection absorption transmission line 72 and the second non-reflection absorption transmission line 73 are both Z c , the resistance values ​​of the first non-reflection absorption resistor 76 and the second non-reflection absorption resistor 77 are both R2; by adjusting Z a , Z c and R2 to adjust the reflection-free characteristics of the balanced differential signal input port A and the unbalanced signal output port.

[0037] The filtering characteristics of the balanced-unbalanced power divider are improved by adjusting the first filtering power splitter coupling line 70 and the second filtering power splitter coupling line 71.

[0038] The characteristic impedances of the first non-reflection absorbing open line 74 and the second non-reflection absorbing open line 75 are both Z b By adjusting Z b This adjusts the position of the transmission zeros on both sides of the passband.

[0039] The isolation characteristics of the two unbalanced signal output ports are improved by adjusting the isolation network 11 .

[0040] In order to further illustrate the balanced-unbalanced power divider with broadband reflectionless filtering characteristics provided by the present invention, a specific example implemented based on the technical solution of the present invention is described in detail below, but the protection scope of the present invention is not limited to the following embodiments, and the methods used in the following embodiments are all conventional methods unless otherwise specified.

[0041] Specific example: This example lists a balanced-unbalanced power divider with broadband non-reflection filtering characteristics. Figure 2As shown, the balanced-unbalanced power divider with broadband non-reflection filtering characteristics described in the present invention has a differential mode to single-ended transmission coefficient |S in the operating frequency band of 1.81 GHz to 2.19 GHz. sd2A |、|S sd3A | is -3.01±0.3dB, achieving broadband equal power distribution of differential signals; |S sd2A | and |S sd3A |Two transmission zeros are introduced at 1.1GHz and 2.9GHz, and the differential mode to two-port and three-port |S sd2A |、|S sd3A | is less than -27dB outside the working frequency band, which improves the frequency selectivity and out-of-band suppression capability of the filter power divider; the balanced port reflection coefficient |S under the excitation of the differential mode signal at the center frequency of 2GHz ddAA | Less than -45dB, the balanced end achieves ideal impedance matching characteristics; balanced end differential mode reflection coefficient |S ddAA | Less than -11dB in the frequency range of 0.92GHz to 3.08GHz, achieving broadband reflection-free filtering characteristics at balanced input; unbalanced single-ended reflection coefficient |S 22 |、|S 33 |In the frequency range of 0GHz to 4GHz, it is less than -11dB, achieving broadband non-reflection filtering characteristics when unbalanced single-ended input. Figure 3 As shown, the transmission coefficient of the balanced-unbalanced power divider with broadband non-reflection filtering characteristics described in the present invention to the two-port and three-port under the common-mode signal excitation condition |S sc2A | and |S sc3A | Less than -45dB at the center frequency 2GHz, |S sc2A |、|S sc3A |In the frequency range of 0GHz to 4GHz, it is less than -8dB, achieving broadband common mode suppression. Figure 4 As shown, the phase difference between the output signals of port 2 and port 3 of the balanced-unbalanced power divider with broadband non-reflection filtering characteristics described in the present invention is 180 degrees.

[0042] In summary, the balanced-unbalanced power divider with broadband non-reflection filtering characteristics provided by the present invention simultaneously realizes highly selective filtering characteristics, conversion function of balanced differential signals to unbalanced single-ended signals, good common-mode suppression, two-way broadband equal power distribution, 180-degree output signal phase difference characteristics, and both the balanced end and the unbalanced single end have broadband non-reflection filtering characteristics. It is very suitable for application in various balanced-unbalanced microwave systems to improve their overall performance.

[0043] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A balanced-unbalanced power divider with broadband non-reflection filtering characteristics, characterized in that include: A balanced differential signal input port A, two unbalanced signal output ports, two reflection-free filter power division networks, two quarter-wavelength anti-connected wiring sections, two quarter-wavelength signal transmission lines and an isolation network (11); The balanced differential signal input port A includes an input port A+(1) and an input port A-(4); The two unbalanced signal output ports include output port two (2) and output port three (3); The two reflectionless filtering power division networks include a first reflectionless filtering power division network (7) and a second reflectionless filtering power division network (8); The two quarter-wavelength anti-connected wirings include a first anti-connected wiring (5) and a second anti-connected wiring (6); wherein one end of the first anti-connected wiring (5) is connected to the connection between the input port A+ (1) and the first reflection-free filter power division network (7), and the other end is connected to the second anti-connected wiring (6); one end of the second anti-connected wiring (6) is connected to the connection between the input port A- (4) and the second reflection-free filter power division network (8), and the other end is connected to the first anti-connected wiring (5); One end of the first non-reflection filter power division network (7) is connected to the connection point between the first anti-connected wiring (5) and the input port A+ (1), and the other end is connected to the first signal transmission line (9); one end of the second non-reflection filter power division network (8) is connected to the connection point between the second anti-connected wiring (6) and the input port A- (2), and the other end is connected to the second signal transmission line (10); The first non-reflection filtering power division network (7) and the second non-reflection filtering power division network (8) have the same structure; the first non-reflection filtering power division network (7) comprises a first filtering power open circuit coupling line (70), a second filtering power open circuit coupling line (71), a first non-reflection absorbing transmission line (72), a second non-reflection absorbing transmission line (73), a first non-reflection absorbing open circuit line (74), a second non-reflection absorbing open circuit line (75), a first non-reflection absorbing resistor (76), a second non-reflection absorbing resistor (77) and a non-reflection absorbing short circuit line (78); The first port (701) of the first filter power split coupling line (70) is connected to the input port A+(1), the second port (702) is connected to the first non-reflection absorption transmission line (72), the third port (703) is open-circuited, and the fourth port (704) is connected to the fourth port (714) of the second filter power split coupling line (71); the first port (711) of the second filter power split coupling line (71) is connected to the first signal transmission line (9), the second port (712) is connected to the second non-reflection absorption transmission line (73), the third port (713) is open-circuited, and the fourth port (714) is connected to the fourth port (704) of the first filter power split coupling line (70); one end of the first non-reflection absorption transmission line (72) is connected to the second port (702) of the first filter power split coupling line (70), and the other end is connected to the first non-reflection absorption open line (74) and the first non-reflection absorption resistor ( 76); one end of the second non-reflection absorption transmission line (73) is connected to the second port (712) of the second filter power open circuit coupling line (71), and the other end is connected to the connection between the second non-reflection absorption open line (75) and the second non-reflection absorption resistor (77); one end of the first non-reflection absorption resistor (76) is connected to the connection between the first non-reflection absorption open line (74) and the first non-reflection absorption transmission line (72), and the other end is connected to the connection between the non-reflection absorption short line (78) and the second non-reflection absorption resistor (77); one end of the second non-reflection absorption resistor (77) is connected to the connection between the second non-reflection absorption open line (75) and the second non-reflection absorption transmission line (73), and the other end is connected to the connection between the non-reflection absorption short line (78) and the first non-reflection absorption resistor (76); the non-reflection absorption short line (78) is connected to the connection between the first non-reflection absorption resistor (76) and the second non-reflection absorption resistor (77); The two quarter-wavelength signal transmission lines include a first signal transmission line (9) and a second signal transmission line (10); wherein one end of the first signal transmission line (9) is connected to the first reflection-free filter power division network (7), and the other end is connected to the connection between the isolation network (11) and the second output port (2); one end of the second signal transmission line (10) is connected to the second reflection-free filter power division network (8), and the other end is connected to the connection between the isolation network (11) and the third output port (3); One end of the isolation network (11) is connected to the connection between the first signal transmission line (9) and the second output port (2), and the other end is connected to the connection between the second signal transmission line (10) and the third output port (3); the isolation network (11) comprises a first isolation resistor (111), a half-wavelength transmission line (112) and a second isolation resistor (112); one end of the first isolation resistor (111) is connected to the connection between the first signal transmission line (9) and the second output port (2), and the other end is connected to the half-wavelength transmission line (112); one end of the half-wavelength transmission line (112) is connected to the first isolation resistor (111), and the other end is connected to the second isolation resistor (113); one end of the second isolation resistor (113) is connected to the half-wavelength transmission line (112), and the other end is connected to the connection between the second signal transmission line (10) and the third output port (3).

2. A balanced-unbalanced power divider with broadband non-reflection filtering characteristics according to claim 1, characterized in that: The characteristic impedance of the non-reflective absorption short-circuit line (78) is Z a The characteristic impedances of the first non-reflection absorption transmission line (72) and the second non-reflection absorption transmission line (73) are both Z c , the resistance values ​​of the first non-reflection absorption resistor (76) and the second non-reflection absorption resistor (77) are both R2; by adjusting Z a , Z c and R2 to adjust the reflection-free characteristics of the balanced differential signal input port A and the unbalanced signal output port.

3. A balanced-unbalanced power divider with broadband non-reflection filtering characteristics according to claim 1, characterized in that: The filtering characteristics of the balanced-unbalanced power divider are improved by adjusting the first filtering power splitter circuit coupling line (70) and the second filtering power splitter circuit coupling line (71).

4. A balanced-unbalanced power divider with broadband non-reflection filtering characteristics according to claim 1, characterized in that: The characteristic impedances of the first non-reflection absorbing open line (74) and the second non-reflection absorbing open line (75) are both Z b By adjusting Z b This adjusts the position of the transmission zeros on both sides of the passband.

5. The balanced-unbalanced power divider with broadband non-reflection filtering characteristics according to claim 1, characterized in that: The isolation characteristics of the two unbalanced signal output ports are improved by adjusting the isolation network (11).

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