Balanced common-mode non-reflective non-magnetic nonreciprocal band-pass filter

Abstract

The invention discloses a balanced type common-mode non-reflection non-magnetic nonreciprocal band-pass filter. Comprising a balanced differential input port A, a balanced differential output port B, four sections of quarter-wavelength differential connecting lines, two common-mode non-reflection absorption resistors, four sections of quarter-wavelength admittance conversion connecting lines, two sections of half-wavelength resonant microstrip lines, four sections of half-wavelength open-circuit transmission lines and two sections of full-wavelength time modulation resonant microstrip lines, the antenna comprises four microstrip lines, four varactors, two quarter-wavelength feed microstrip lines, two T-shaped grounding impedance conversion microstrip lines and two power supplies. The balanced non-magnetic non-reciprocal filter is designed and manufactured by adopting a microstrip line, and is integrated with other circuits on a single PCB (Printed Circuit Board). By adding the differential connecting lines and the absorption resistors at the balanced input and output ports, the good common-mode non-reflection characteristic is realized, and the common-mode non-reflection characteristic can be independently adjusted by adjusting the differential connecting lines and the absorption resistors without influencing the differential-mode response.

Description

Technical Field

[0001] The invention relates to a balanced bandpass filter, in particular to a balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter. Background Art

[0002] Nonreciprocal components such as circulators, isolators and gyrators play an important role in numerous microwave wireless applications, such as high-power transmitters, simultaneous on-frequency transmission and reception communications and radar systems, as well as emerging low-temperature quantum computing. Currently, such components are mainly realized by ferrite materials. However, ferrite materials are bulky and costly, and are incompatible with semiconductor integrated circuit manufacturing processes. This has inspired researchers to conduct extensive research on non-magnetic nonreciprocal components. Recently, nonreciprocal technology based on time-modulated resonators has been proposed and has received widespread attention.

[0003] With the rapid development of modern wireless communication technology, the amount of information transmitted in mobile communication systems continues to increase, and various components work in increasingly complex electromagnetic environments, so circuits need to have stronger anti-interference capabilities. Compared with traditional single-ended circuits, balanced microwave circuits have higher immunity to noise, electromagnetic interference and crosstalk in complex circuits, and have better electromagnetic compatibility characteristics. In many applications, balanced circuits are superior to single-ended circuits, such as RF systems, high-speed digital circuits, and CMOS integrated circuits.

[0004] For the common-mode noise in balanced microwave circuits, the existing balanced non-reciprocal bandpass filter design based on time-modulated resonators is implemented in the form of a reflective filter, that is, by reflecting the energy of unwanted frequency components back to the signal source to achieve the purpose of common-mode noise suppression. In nonlinear systems, the aliasing between reflected signals and existing signals will generate many interference signals, which will have a significant impact on system performance. By introducing the common-mode non-reflective part of the loading resistor, the common-mode noise can be dissipated in the form of heat energy, avoiding the potential harm of common-mode noise suppression in the form of reflection to the system. In view of this, it is indeed necessary to propose a balanced common-mode non-reflective non-magnetic non-reciprocal bandpass filter. Summary of the invention

[0005] Based on this, in order to solve the shortcomings of the existing technology, a balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter is proposed, including: a balanced differential input port A, a balanced differential output port B, four sections of quarter-wavelength differential connecting lines, two common-mode non-reflection absorption resistors, four sections of quarter-wavelength admittance transformation connecting lines, two sections of half-wavelength resonant microstrip lines, four sections of half-wavelength open-circuit transmission lines, two sections of full-wavelength time-modulated resonant microstrip lines, four varactor diodes, two sections of quarter-wavelength feeding microstrip lines, two sections of T-type grounded impedance transformation microstrip lines and two power supplies;

[0006] The balanced differential input port A includes an input port A+ and an input port A-;

[0007] The balanced differential output port B includes an output port B+ and an output port B-;

[0008] The four-segment quarter-wavelength differential connection line includes a first differential connection line, a second differential connection line, a third differential connection line and a fourth differential connection line; one end of the first differential connection line is connected to the connection between the input port A+ and the first admittance conversion connection line, and the other end is connected to the connection between the third differential connection line and the first common-mode non-reflection absorption resistor; one end of the second differential connection line is connected to the connection between the output port B+ and the second admittance conversion connection line, and the other end is connected to the connection between the fourth differential connection line and the second common-mode non-reflection absorption resistor; one end of the third differential connection line is connected to the connection between the input port A- and the third admittance conversion connection line, and the other end is connected to the connection between the first differential connection line and the first common-mode non-reflection absorption resistor; one end of the fourth differential connection line is connected to the connection between the output port B- and the fourth admittance conversion connection line, and the other end is connected to the connection between the second differential connection line and the second common-mode non-reflection absorption resistor;

[0009] The two common-mode non-reflection absorption resistors include a first common-mode non-reflection absorption resistor and a second common-mode non-reflection absorption resistor; one end of the first common-mode non-reflection absorption resistor is connected to the connection between the first differential connection line and the third differential connection line, and the other end is grounded; one end of the second common-mode non-reflection absorption resistor is connected to the connection between the second differential connection line and the fourth differential connection line, and the other end is grounded;

[0010] The four sections of quarter-wavelength admittance conversion connecting lines include a first admittance conversion connecting line, a second admittance conversion connecting line, a third admittance conversion connecting line and a fourth admittance conversion connecting line; one end of the first admittance conversion connecting line is connected to the connection between the input port A+ and the first differential connecting line, and the other end is connected to the connection between the first resonant microstrip line and the first open transmission line; one end of the second admittance conversion connecting line is connected to the connection between the output port B+ and the second differential connecting line, and the other end is connected to the connection between the second resonant microstrip line and the second open transmission line; one end of the third admittance conversion connecting line is connected to the connection between the input port A- and the third differential connecting line, and the other end is connected to the connection between the first resonant microstrip line and the third open transmission line; one end of the fourth admittance conversion connecting line is connected to the connection between the output port B- and the fourth differential connecting line, and the other end is connected to the connection between the second resonant microstrip line and the fourth open transmission line;

[0011] The two sections of half-wavelength resonant microstrip lines include a first resonant microstrip line and a second resonant microstrip line; one end of the first resonant microstrip line is connected to the connection between the first admittance conversion connecting line and the first open transmission line, and the other end is connected to the connection between the third admittance conversion connecting line and the third open transmission line; one end of the second resonant microstrip line is connected to the connection between the second admittance conversion connecting line and the second open transmission line, and the other end is connected to the connection between the fourth admittance conversion connecting line and the fourth open transmission line;

[0012] The four sections of half-wavelength open transmission lines include a first open transmission line, a second open transmission line, a third open transmission line and a fourth open transmission line; one end of the first open transmission line is connected to the connection between the first admittance transformation connection line and the first resonant microstrip line, and the other end is open; one end of the second open transmission line is connected to the connection between the second admittance transformation connection line and the second resonant microstrip line, and the other end is open; one end of the third open transmission line is connected to the connection between the third admittance transformation connection line and the first resonant microstrip line, and the other end is open; one end of the fourth open transmission line is connected to the connection between the fourth admittance transformation connection line and the second resonant microstrip line, and the other end is open;

[0013] The two sections of full-wavelength time-modulated resonant microstrip lines include a first time-modulated resonant microstrip line and a second time-modulated resonant microstrip line; the first time-modulated resonant microstrip line includes a first coupled resonant microstrip line and a second coupled resonant microstrip line; the second time-modulated resonant microstrip line includes a third coupled resonant microstrip line and a fourth coupled resonant microstrip line; one end of the first coupled resonant microstrip line is connected to the cathode of the first varactor diode, and the other end is connected to the connection between the second coupled resonant microstrip line and the first feeding microstrip line; one end of the second coupled resonant microstrip line is connected to the cathode of the third varactor diode, and the other end is connected to the connection between the first coupled resonant microstrip line and the first feeding microstrip line; one end of the third coupled resonant microstrip line is connected to the cathode of the second varactor diode, and the other end is connected to the connection between the fourth coupled resonant microstrip line and the second feeding microstrip line; one end of the fourth coupled resonant microstrip line is connected to the cathode of the fourth varactor diode, and the other end is connected to the connection between the third coupled resonant microstrip line and the second feeding microstrip line;

[0014] The four varactor diodes include a first varactor diode, a second varactor diode, a third varactor diode and a fourth varactor diode; the cathode of the first varactor diode is connected to the first coupled resonant microstrip line, and the anode is connected to the first T-type grounded impedance transformation microstrip line; the cathode of the second varactor diode is connected to the third coupled resonant microstrip line, and the anode is connected to the first T-type grounded impedance transformation microstrip line; the cathode of the third varactor diode is connected to the second coupled resonant microstrip line, and the anode is connected to the second T-type grounded impedance transformation microstrip line; the cathode of the fourth varactor diode is connected to the fourth coupled resonant microstrip line, and the anode is connected to the second T-type grounded impedance transformation microstrip line;

[0015] The two quarter-wavelength feeding microstrip lines include a first feeding microstrip line and a second feeding microstrip line; one end of the first feeding microstrip line is connected to the connection between the first coupled resonant microstrip line and the second coupled resonant microstrip line, and the other end is connected to the first power supply; one end of the second feeding microstrip line is connected to the connection between the third coupled resonant microstrip line and the fourth coupled resonant microstrip line, and the other end is connected to the second power supply;

[0016] The two sections of T-type grounded impedance transformation microstrip lines include a first T-type grounded impedance transformation microstrip line and a second T-type grounded impedance transformation microstrip line; one end of the first T-type grounded impedance transformation microstrip line is connected to the anode of the first varactor diode, and the other end is connected to the anode of the second varactor diode; one end of the second T-type grounded impedance transformation microstrip line is connected to the anode of the third varactor diode, and the other end is connected to the anode of the fourth varactor diode;

[0017] The two power supplies include a first power supply and a second power supply; the first power supply is connected to a first feeding microstrip line; the second power supply is connected to a second feeding microstrip line;

[0018] The horizontal quarter-wavelength portions of the first open transmission line and the first coupled resonant microstrip line are parallel to each other and there is a coupling effect; the horizontal quarter-wavelength portions of the second open transmission line and the third coupled resonant microstrip line are parallel to each other and there is a coupling effect; the horizontal quarter-wavelength portions of the third open transmission line and the second coupled resonant microstrip line are parallel to each other and there is a coupling effect; the horizontal quarter-wavelength portions of the fourth open transmission line and the fourth coupled resonant microstrip line are parallel to each other and there is a coupling effect.

[0019] By adjusting the DC voltage V output by the first power supply dc , AC voltage amplitude V ac , frequency f m , the starting phase φ1 and the DC voltage V output by the second power supply dc , AC voltage amplitude V ac , frequency f m, starting phase φ2, time modulation is performed to control the transmission of the forward differential signal and realize the cutoff of the reverse differential signal at the same time, thereby realizing the non-reciprocity of the balanced common-mode non-reflection and non-tape pass filter.

[0020] The first power supply and the second power supply only output a DC voltage V dc When , the filter is a balanced common-mode non-reflection reciprocal bandpass filter.

[0021] The structure of the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter is symmetrical in top and bottom and in left and right. By adjusting the characteristic impedance of the first differential connection line, the characteristic impedance of the second differential connection line, the characteristic impedance of the third differential connection line, the characteristic impedance of the fourth differential connection line, the resistance value of the first common-mode non-reflection absorption resistor and the resistance value of the second common-mode non-reflection absorption resistor, the common-mode non-reflection absorption characteristics of the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter are adjusted without affecting the differential mode response.

[0022] The symmetrical points of two half-wavelength resonant microstrip lines are equivalent to virtual open circuits under the excitation of common-mode signals, showing a common-mode signal band-stop response, thereby realizing common-mode suppression characteristics; four half-wavelength open transmission lines are respectively coupled with the horizontal quarter-wavelength parts of the first coupled resonant microstrip line, the second coupled resonant microstrip line, the third coupled resonant microstrip line and the fourth coupled resonant microstrip line, showing a full-impedance response under the excitation of common-mode signals, thereby improving the common-mode suppression characteristics.

[0023] The passband bandwidth and frequency selectivity of the balanced common-mode non-reflection and non-magnetic non-reciprocal bandpass filter are adjusted by adjusting the characteristic impedance of four quarter-wavelength admittance transformation connecting lines, the distance between the first open transmission line and the first coupled resonant microstrip line, the distance between the second open transmission line and the third coupled resonant microstrip line, the distance between the third open transmission line and the second coupled resonant microstrip line, the distance between the fourth open transmission line and the fourth coupled resonant microstrip line, and the size of two sections of T-type grounded impedance transformation microstrip lines.

[0024] In order to improve the anti-interference ability of the balanced non-reciprocal bandpass filter and realize the functional expansion of the common-mode non-reflection characteristic, the present invention provides a balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter. The balanced non-magnetic non-reciprocal filter is designed and manufactured using microstrip lines and can be integrated with other circuits on a single PCB circuit board. By adding differential connection lines and absorption resistors at the balanced input and output ports, good common-mode non-reflection characteristics are achieved, and the common-mode non-reflection characteristics can be independently adjusted by adjusting the differential connection lines and absorption resistors without affecting the differential mode response. When using the differential / common mode signal transmission, the different circuit equivalent relationships of the horizontal symmetry plane of the circuit are used to achieve an excellent common-mode suppression effect. At the same time, for the circuit part that realizes the non-reciprocal response based on the time modulation resonator, the adjustment of the DC voltage and the sinusoidal modulation signal in the power supply does not affect the common mode response. The overall circuit design meets the requirements of strong anti-interference ability, easy integration and strong electromagnetic compatibility of modern communication systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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.

[0026] Figure 1 It is a structural schematic diagram of a balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter of the present invention;

[0027] Figure 2 It is a differential mode S parameter amplitude curve diagram of a balanced common mode non-reflection non-magnetic non-reciprocal bandpass filter of the present invention in a state without time modulation;

[0028] Figure 3 The invention is a balanced common mode non-reflection non-magnetic non-reciprocal bandpass filter in a differential mode|S in a time modulation state. ddBA | and |S ddBA | Curve graph;

[0029] Figure 4 The invention is a balanced common mode non-reflection non-magnetic non-reciprocal bandpass filter in a differential mode|S in a time modulation state. ddAA | Curve graph;

[0030] Figure 5 The present invention discloses a common-mode S parameter amplitude curve diagram of a balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter in a time modulation state. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The invention discloses a balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter, comprising: a balanced differential input port A, a balanced differential output port B, four sections of quarter-wavelength differential connecting lines, two common-mode non-reflection absorbing resistors, four sections of quarter-wavelength admittance transformation connecting lines, two sections of half-wavelength resonant microstrip lines, four sections of half-wavelength open-circuit transmission lines, two sections of full-wavelength time-modulated resonant microstrip lines, four varactor diodes, two sections of quarter-wavelength feeding microstrip lines, two sections of T-type grounded impedance transformation microstrip lines and two power supplies;

[0033] The balanced differential input port A includes an input port A+1 and an input port A-3;

[0034] The balanced differential output port B includes an output port B+2 and an output port B-4;

[0035] The four-segment quarter-wavelength differential connection line includes a first differential connection line 5, a second differential connection line 6, a third differential connection line 7 and a fourth differential connection line 8; one end of the first differential connection line 5 is connected to the connection between the input port A+1 and the first admittance conversion connection line 11, and the other end is connected to the connection between the third differential connection line 7 and the first common-mode non-reflection absorption resistor 9; one end of the second differential connection line 6 is connected to the connection between the output port B+2 and the second admittance conversion connection line 12, and the other end is connected to the connection between the fourth differential connection line 8 and the second common-mode non-reflection absorption resistor 10; one end of the third differential connection line 7 is connected to the connection between the input port A-3 and the third admittance conversion connection line 13, and the other end is connected to the connection between the first differential connection line 5 and the first common-mode non-reflection absorption resistor 9; one end of the fourth differential connection line 8 is connected to the connection between the output port B-4 and the fourth admittance conversion connection line 14, and the other end is connected to the connection between the second differential connection line 6 and the second common-mode non-reflection absorption resistor 10;

[0036] The two common-mode non-reflection absorption resistors include a first common-mode non-reflection absorption resistor 9 and a second common-mode non-reflection absorption resistor 10; one end of the first common-mode non-reflection absorption resistor 9 is connected to the connection between the first differential connection line 5 and the third differential connection line 7, and the other end is grounded; one end of the second common-mode non-reflection absorption resistor 10 is connected to the connection between the second differential connection line 6 and the fourth differential connection line 8, and the other end is grounded;

[0037] The four quarter-wavelength admittance conversion connecting lines include a first admittance conversion connecting line 11, a second admittance conversion connecting line 12, a third admittance conversion connecting line 13 and a fourth admittance conversion connecting line 14; one end of the first admittance conversion connecting line 11 is connected to the connection between the input port A+1 and the first differential connecting line 5, and the other end is connected to the connection between the first resonant microstrip line 15 and the first open transmission line 17; one end of the second admittance conversion connecting line 12 is connected to the connection between the output port B+2 and the second differential connecting line 6, and the other end is connected to the connection between the second resonant microstrip line 16 and the second open transmission line 18; one end of the third admittance conversion connecting line 13 is connected to the connection between the input port A-3 and the third differential connecting line 7, and the other end is connected to the connection between the first resonant microstrip line 15 and the third open transmission line 19; one end of the fourth admittance conversion connecting line 14 is connected to the connection between the output port B-4 and the fourth differential connecting line 8, and the other end is connected to the connection between the second resonant microstrip line 16 and the fourth open transmission line 20;

[0038] The two sections of half-wavelength resonant microstrip lines include a first resonant microstrip line 15 and a second resonant microstrip line 16; one end of the first resonant microstrip line 15 is connected to the connection between the first admittance conversion connecting line 11 and the first open transmission line 17, and the other end is connected to the connection between the third admittance conversion connecting line 13 and the third open transmission line 19; one end of the second resonant microstrip line 16 is connected to the connection between the second admittance conversion connecting line 12 and the second open transmission line 18, and the other end is connected to the connection between the fourth admittance conversion connecting line 14 and the fourth open transmission line 20;

[0039] The four sections of half-wavelength open transmission lines include a first open transmission line 17, a second open transmission line 18, a third open transmission line 19 and a fourth open transmission line 20; one end of the first open transmission line 17 is connected to the connection between the first admittance conversion connection line 11 and the first resonant microstrip line 15, and the other end is open; one end of the second open transmission line 18 is connected to the connection between the second admittance conversion connection line 12 and the second resonant microstrip line 16, and the other end is open; one end of the third open transmission line 19 is connected to the connection between the third admittance conversion connection line 13 and the first resonant microstrip line 15, and the other end is open; one end of the fourth open transmission line 20 is connected to the connection between the fourth admittance conversion connection line 14 and the second resonant microstrip line 16, and the other end is open;

[0040] The two sections of full-wavelength time-modulated resonant microstrip lines include a first time-modulated resonant microstrip line 21 and a second time-modulated resonant microstrip line 22; the first time-modulated resonant microstrip line 21 includes a first coupled resonant microstrip line 211 and a second coupled resonant microstrip line 212; the second time-modulated resonant microstrip line 22 includes a third coupled resonant microstrip line 221 and a fourth coupled resonant microstrip line 222; one end of the first coupled resonant microstrip line 211 is connected to the cathode of the first varactor diode 23, and the other end is connected to the connection between the second coupled resonant microstrip line 212 and the first feeding microstrip line 27; One end of the second coupled resonant microstrip line 212 is connected to the cathode of the third varactor diode 25, and the other end is connected to the connection between the first coupled resonant microstrip line 211 and the first feeding microstrip line 27; one end of the third coupled resonant microstrip line 221 is connected to the cathode of the second varactor diode 24, and the other end is connected to the connection between the fourth coupled resonant microstrip line 222 and the second feeding microstrip line 28; one end of the fourth coupled resonant microstrip line 222 is connected to the cathode of the fourth varactor diode 26, and the other end is connected to the connection between the third coupled resonant microstrip line 221 and the second feeding microstrip line 28;

[0041] The four varactor diodes include a first varactor diode 23, a second varactor diode 24, a third varactor diode 25 and a fourth varactor diode 26; the cathode of the first varactor diode 23 is connected to the first coupled resonant microstrip line 211, and the anode is connected to the first T-type grounded impedance transformation microstrip line 29; the cathode of the second varactor diode 24 is connected to the third coupled resonant microstrip line 221, and the anode is connected to the first T-type grounded impedance transformation microstrip line 29; the cathode of the third varactor diode 25 is connected to the second coupled resonant microstrip line 212, and the anode is connected to the second T-type grounded impedance transformation microstrip line 30; the cathode of the fourth varactor diode 26 is connected to the fourth coupled resonant microstrip line 222, and the anode is connected to the second T-type grounded impedance transformation microstrip line 30;

[0042] The two quarter-wavelength feeding microstrip lines include a first feeding microstrip line 27 and a second feeding microstrip line 28; one end of the first feeding microstrip line 27 is connected to the connection between the first coupled resonant microstrip line 211 and the second coupled resonant microstrip line 212, and the other end is connected to the first power supply 31; one end of the second feeding microstrip line 28 is connected to the connection between the third coupled resonant microstrip line 221 and the fourth coupled resonant microstrip line 222, and the other end is connected to the second power supply 32;

[0043] The two sections of T-type grounded impedance transformation microstrip lines include a first T-type grounded impedance transformation microstrip line 29 and a second T-type grounded impedance transformation microstrip line 30; one end of the first T-type grounded impedance transformation microstrip line 29 is connected to the anode of the first varactor diode 23, and the other end is connected to the anode of the second varactor diode 24; one end of the second T-type grounded impedance transformation microstrip line 30 is connected to the anode of the third varactor diode 25, and the other end is connected to the anode of the fourth varactor diode 26;

[0044] The two power supplies include a first power supply 31 and a second power supply 32; the first power supply 31 is connected to the first feeding microstrip line 27; the second power supply 32 is connected to the second feeding microstrip line 28;

[0045] The first open transmission line 17 and the horizontal quarter-wavelength portion of the first coupled resonant microstrip line 211 are parallel to each other and there is a coupling effect; the second open transmission line 18 and the horizontal quarter-wavelength portion of the third coupled resonant microstrip line 221 are parallel to each other and there is a coupling effect; the third open transmission line 19 and the horizontal quarter-wavelength portion of the second coupled resonant microstrip line 212 are parallel to each other and there is a coupling effect; the fourth open transmission line 20 and the horizontal quarter-wavelength portion of the fourth coupled resonant microstrip line 222 are parallel to each other and there is a coupling effect.

[0046] By adjusting the DC voltage V output by the first power supply 31 dc , AC voltage amplitude V ac , frequency f m , the starting phase φ1 and the DC voltage V output by the second power supply 32 dc , AC voltage amplitude V ac , frequency f m , starting phase φ2, time modulation is performed to control the transmission of the forward differential signal and realize the cutoff of the reverse differential signal at the same time, thereby realizing the non-reciprocity of the balanced common-mode non-reflection and non-tape pass filter.

[0047] The first power supply 31 and the second power supply 32 only output a DC voltage V dc When , the filter is a balanced common-mode non-reflection reciprocal bandpass filter.

[0048] The structure of the balanced common-mode non-reflection, non-magnetic, non-reciprocal bandpass filter is symmetrical up and down and left and right; by adjusting the characteristic impedance of the first differential connection line 5, the characteristic impedance of the second differential connection line 6, the characteristic impedance of the third differential connection line 7, the characteristic impedance of the fourth differential connection line 8, the resistance value of the first common-mode non-reflection absorption resistor 9 and the resistance value of the second common-mode non-reflection absorption resistor 10, the common-mode non-reflection absorption characteristics of the balanced common-mode non-reflection, non-magnetic, non-reciprocal bandpass filter are adjusted without affecting the differential mode response.

[0049] The symmetrical points of two half-wavelength resonant microstrip lines are equivalent to virtual open circuits under common-mode signal excitation, showing a common-mode signal band-stop response, thereby realizing common-mode suppression characteristics; four half-wavelength open transmission lines are respectively coupled with the horizontal quarter-wavelength parts of the first coupled resonant microstrip line 211, the second coupled resonant microstrip line 212, the third coupled resonant microstrip line 221 and the fourth coupled resonant microstrip line 222, showing a full-impedance response under common-mode signal excitation, thereby improving common-mode suppression characteristics.

[0050] By adjusting the characteristic impedance of four quarter-wavelength admittance transformation connecting lines, the distance between the first open transmission line 17 and the first coupled resonant microstrip line 211, the distance between the second open transmission line 18 and the third coupled resonant microstrip line 221, the distance between the third open transmission line 19 and the second coupled resonant microstrip line 212, the distance between the fourth open transmission line 20 and the fourth coupled resonant microstrip line 222, and the size of the two sections of T-type grounded impedance transformation microstrip lines, the passband bandwidth and frequency selectivity of the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter are adjusted.

[0051] In order to further illustrate a balanced common-mode non-reflection, non-magnetic, non-reciprocal bandpass filter 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.

[0052] Specific example: This example lists a balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter. Figure 2 As shown, the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter described in the present invention exhibits reciprocity when no time modulation is performed; the filter passband center frequency is 1.5 GHz, the 3 dB relative bandwidth is 9.3%, and the differential mode reflection coefficient in the filter band |S ddAA |Less than -20.6dB, minimum differential mode transmission loss within the filter band|S ddBA | is -2.22dB; Figure 3 As shown, the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter described in the present invention exhibits non-reciprocity in the time modulation state; the filter passband center frequency is 1.5GHz, and the minimum forward differential mode transmission loss in the filter band |S ddBA | is -3.7dB, and the reverse transmission coefficient in the filter band |S ddAB |The bandwidth less than -20dB is 49MHz; Figure 4 As shown, in the time-modulated state, the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter of the present invention has a differential mode reflection coefficient |S at the center frequency of 1.5 GHz. ddAA | is -19.8dB; Figure 5 As shown, the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter described in the present invention has a common-mode reflection coefficient |S under time modulation state. ccAA |In the frequency range of 1.11GHz to 1.92GHz, the common mode transmission coefficient is less than -20dB. ccBA |In the frequency range of 1.11GHz to 1.84GHz, it is less than -70dB. This shows that the balanced common-mode non-reflection-free magnetic-free non-reciprocal bandpass filter described in the present invention has excellent common-mode suppression and common-mode non-reflection characteristics in the time modulation state, and has good differential-mode forward filtering transmission and differential-mode reverse isolation characteristics.

[0053] In summary, the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter described in the present invention can be implemented on a single PCB board and is easy to integrate. In addition, the balanced non-reciprocal filter can be used as an isolator to suppress differential mode reverse interference signals, and as a filter, it can achieve frequency selectivity and can also achieve non-reflection absorption characteristics under common mode excitation, which helps to improve the electromagnetic compatibility characteristics of the communication system. These characteristics are in line with the development trend of multifunctional collaborative design of modern wireless communication circuits, and are therefore very suitable for application in various balanced communication systems to improve the overall performance of the system.

[0054] 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 common-mode non-reflection non-magnetic non-reciprocal bandpass filter, characterized in that: include: Balanced differential input port A, balanced differential output port B, four sections of quarter-wavelength differential connecting lines, two common-mode non-reflective absorption resistors, four sections of quarter-wavelength admittance transformation connecting lines, two sections of half-wavelength resonant microstrip lines, four sections of half-wavelength open-circuit transmission lines, two sections of full-wavelength time-modulated resonant microstrip lines, four variable capacitance diodes, two sections of quarter-wavelength feeding microstrip lines, two sections of T-type grounded impedance transformation microstrip lines and two power supplies; The balanced differential input port A includes an input port A+(1) and an input port A-(3); The balanced differential output port B includes an output port B+(2) and an output port B-(4); The four quarter-wavelength differential connection lines include a first differential connection line (5), a second differential connection line (6), a third differential connection line (7) and a fourth differential connection line (8); one end of the first differential connection line (5) is connected to the connection between the input port A+ (1) and the first admittance conversion connection line (11), and the other end is connected to the connection between the third differential connection line (7) and the first common-mode non-reflection absorption resistor (9); one end of the second differential connection line (6) is connected to the connection between the output port B+ (2) and the second admittance conversion connection line (12), and the other end is connected to the The fourth differential connection line (8) is connected to the connection point of the second common-mode non-reflection absorption resistor (10); one end of the third differential connection line (7) is connected to the connection point of the input port A-(3) and the third admittance conversion connection line (13), and the other end is connected to the connection point of the first differential connection line (5) and the first common-mode non-reflection absorption resistor (9); one end of the fourth differential connection line (8) is connected to the connection point of the output port B-(4) and the fourth admittance conversion connection line (14), and the other end is connected to the connection point of the second differential connection line (6) and the second common-mode non-reflection absorption resistor (10); The two common-mode non-reflection absorption resistors include a first common-mode non-reflection absorption resistor (9) and a second common-mode non-reflection absorption resistor (10); one end of the first common-mode non-reflection absorption resistor (9) is connected to the connection point between the first differential connection line (5) and the third differential connection line (7), and the other end is grounded; one end of the second common-mode non-reflection absorption resistor (10) is connected to the connection point between the second differential connection line (6) and the fourth differential connection line (8), and the other end is grounded; The four quarter-wavelength admittance conversion connecting lines include a first admittance conversion connecting line (11), a second admittance conversion connecting line (12), a third admittance conversion connecting line (13) and a fourth admittance conversion connecting line (14); one end of the first admittance conversion connecting line (11) is connected to the connection between the input port A+ (1) and the first differential connecting line (5), and the other end is connected to the connection between the first resonant microstrip line (15) and the first open-circuit transmission line (17); one end of the second admittance conversion connecting line (12) is connected to the output port B+ (2) and the second differential connecting line (6) and the other end is connected to the connection between the second resonant microstrip line (16) and the second open-circuit transmission line (18); one end of the third admittance conversion connection line (13) is connected to the connection between the input port A-(3) and the third differential connection line (7), and the other end is connected to the connection between the first resonant microstrip line (15) and the third open-circuit transmission line (19); one end of the fourth admittance conversion connection line (14) is connected to the connection between the output port B-(4) and the fourth differential connection line (8), and the other end is connected to the connection between the second resonant microstrip line (16) and the fourth open-circuit transmission line (20); The two sections of half-wavelength resonant microstrip lines include a first resonant microstrip line (15) and a second resonant microstrip line (16); one end of the first resonant microstrip line (15) is connected to the connection between the first admittance conversion connecting line (11) and the first open-circuit transmission line (17), and the other end is connected to the connection between the third admittance conversion connecting line (13) and the third open-circuit transmission line (19); one end of the second resonant microstrip line (16) is connected to the connection between the second admittance conversion connecting line (12) and the second open-circuit transmission line (18), and the other end is connected to the connection between the fourth admittance conversion connecting line (14) and the fourth open-circuit transmission line (20); The four sections of half-wavelength open transmission lines include a first open transmission line (17), a second open transmission line (18), a third open transmission line (19) and a fourth open transmission line (20); one end of the first open transmission line (17) is connected to the connection between the first admittance conversion connection line (11) and the first resonant microstrip line (15), and the other end is open; one end of the second open transmission line (18) is connected to the connection between the second admittance conversion connection line (12) and the second resonant microstrip line (16), and the other end is open; one end of the third open transmission line (19) is connected to the connection between the third admittance conversion connection line (13) and the first resonant microstrip line (15), and the other end is open; one end of the fourth open transmission line (20) is connected to the connection between the fourth admittance conversion connection line (14) and the second resonant microstrip line (16), and the other end is open; The two sections of full-wavelength time-modulated resonant microstrip lines include a first time-modulated resonant microstrip line (21) and a second time-modulated resonant microstrip line (22); the first time-modulated resonant microstrip line (21) includes a first coupled resonant microstrip line (211) and a second coupled resonant microstrip line (212); The second time-modulated resonant microstrip line (22) comprises a third coupled resonant microstrip line (221) and a fourth coupled resonant microstrip line (222); one end of the first coupled resonant microstrip line (211) is connected to the cathode of the first variable capacitance diode (23), and the other end is connected to the connection between the second coupled resonant microstrip line (212) and the first feeding microstrip line (27); One end of the second coupled resonant microstrip line (212) is connected to the cathode of the third varactor diode (25), and the other end is connected to the connection between the first coupled resonant microstrip line (211) and the first feeding microstrip line (27); One end of the third coupled resonant microstrip line (221) is connected to the cathode of the second varactor diode (24), and the other end is connected to the connection between the fourth coupled resonant microstrip line (222) and the second feeding microstrip line (28); One end of the fourth coupled resonant microstrip line (222) is connected to the cathode of the fourth varactor diode (26), and the other end is connected to the connection between the third coupled resonant microstrip line (221) and the second feeding microstrip line (28); The four varactor diodes include a first varactor diode (23), a second varactor diode (24), a third varactor diode (25) and a fourth varactor diode (26); the cathode of the first varactor diode (23) is connected to the first coupled resonant microstrip line (211), and the anode is connected to the first T-type grounded impedance transformation microstrip line (29); the cathode of the second varactor diode (24) is connected to the third coupled resonant microstrip line (221), and the anode is connected to the first T-type grounded impedance transformation microstrip line (29); the cathode of the third varactor diode (25) is connected to the second coupled resonant microstrip line (212), and the anode is connected to the second T-type grounded impedance transformation microstrip line (30); the cathode of the fourth varactor diode (26) is connected to the fourth coupled resonant microstrip line (222), and the anode is connected to the second T-type grounded impedance transformation microstrip line (30); The two quarter-wavelength feeding microstrip lines include a first feeding microstrip line (27) and a second feeding microstrip line (28); one end of the first feeding microstrip line (27) is connected to the connection between the first coupling resonant microstrip line (211) and the second coupling resonant microstrip line (212), and the other end is connected to a first power source (31); one end of the second feeding microstrip line (28) is connected to the connection between the third coupling resonant microstrip line (221) and the fourth coupling resonant microstrip line (222), and the other end is connected to a second power source (32); The two sections of T-type grounded impedance transformation microstrip lines include a first T-type grounded impedance transformation microstrip line (29) and a second T-type grounded impedance transformation microstrip line (30); one end of the first T-type grounded impedance transformation microstrip line (29) is connected to the anode of the first variable capacitance diode (23), and the other end is connected to the anode of the second variable capacitance diode (24); one end of the second T-type grounded impedance transformation microstrip line (30) is connected to the anode of the third variable capacitance diode (25), and the other end is connected to the anode of the fourth variable capacitance diode (26); The two power supplies include a first power supply (31) and a second power supply (32); the first power supply (31) is connected to a first feeding microstrip line (27); and the second power supply (32) is connected to a second feeding microstrip line (28); The horizontal quarter-wavelength portions of the first open transmission line (17) and the first coupled resonant microstrip line (211) are parallel to each other and have a coupling effect; the horizontal quarter-wavelength portions of the second open transmission line (18) and the third coupled resonant microstrip line (221) are parallel to each other and have a coupling effect; the horizontal quarter-wavelength portions of the third open transmission line (19) and the second coupled resonant microstrip line (212) are parallel to each other and have a coupling effect; and the horizontal quarter-wavelength portions of the fourth open transmission line (20) and the fourth coupled resonant microstrip line (222) are parallel to each other and have a coupling effect.

2. A balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter according to claim 1, characterized in that: By adjusting the DC voltage V output by the first power supply (31) dc , AC voltage amplitude V ac , frequency f m , the starting phase φ1 and the DC voltage V output by the second power supply (32) dc , AC voltage amplitude V ac , frequency f m , starting phase φ2, time modulation is performed to control the transmission of the forward differential signal and realize the cutoff of the reverse differential signal at the same time, thereby realizing the non-reciprocity of the balanced common-mode non-reflection and non-tape pass filter.

3. A balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter according to claim 1, characterized in that: The first power supply (31) and the second power supply (32) only output a DC voltage V dc When , the filter is a balanced common-mode non-reflection reciprocal bandpass filter.

4. A balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter according to claim 1, characterized in that: The structure of the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter is symmetrical in both vertical and horizontal directions. By adjusting the characteristic impedance of the first differential connection line (5), the characteristic impedance of the second differential connection line (6), the characteristic impedance of the third differential connection line (7), the characteristic impedance of the fourth differential connection line (8), the resistance value of the first common-mode non-reflection absorption resistor (9) and the resistance value of the second common-mode non-reflection absorption resistor (10), the common-mode non-reflection absorption characteristics of the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter are adjusted without affecting the differential mode response.

5. A balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter according to claim 1, characterized in that: The symmetrical points of two sections of half-wavelength resonant microstrip lines are equivalent to virtual open circuits under the excitation of common-mode signals, showing a common-mode signal band-stop response, thereby realizing common-mode suppression characteristics; four sections of half-wavelength open-circuit transmission lines are respectively coupled with the horizontal quarter-wavelength parts of the first coupled resonant microstrip line (211), the second coupled resonant microstrip line (212), the third coupled resonant microstrip line (221), and the fourth coupled resonant microstrip line (222), showing a full-impedance response under the excitation of common-mode signals, thereby improving the common-mode suppression characteristics.

6. A balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter according to claim 1, characterized in that: By adjusting the characteristic impedance of four quarter-wavelength admittance transformation connecting lines, the distance between the first open-circuit transmission line (17) and the first coupled resonant microstrip line (211), the distance between the second open-circuit transmission line (18) and the third coupled resonant microstrip line (221), the distance between the third open-circuit transmission line (19) and the second coupled resonant microstrip line (212), the distance between the fourth open-circuit transmission line (20) and the fourth coupled resonant microstrip line (222), and the size of the two T-type grounded impedance transformation microstrip lines, the passband bandwidth and frequency selectivity of the balanced common-mode non-reflection non-magnetic non-reciprocal bandpass filter are adjusted.

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