A variable circular polarization device with harmonic suppression

Abstract

The present invention relates to the field of radio ranging, and specifically relates to a variable circular polarization device with harmonic suppression, comprising a four-unit structure and a four-channel amplitude and phase control multifunctional unit. Each unit in the four-unit structure includes a harmonic suppression variable circular polarization unit and a transmit / receive amplification unit. The first and second ports of the harmonic suppression variable circular polarization unit are respectively connected to the H / V polarization ports of the corresponding external antenna unit, and the third port is connected to the common terminal of the transmit / receive amplification unit. The transmitting and receiving ends of the transmit / receive amplification unit are respectively connected to the four corresponding channels of the four-channel amplitude and phase control multifunctional unit. The four-channel amplitude and phase control multifunctional unit is used to achieve signal synthesis and distribution. The present invention introduces a harmonic suppression polarization switch in the harmonic suppression variable circular polarization unit in series with a Lange bridge to achieve switching between left-hand circular polarization and right-hand circular polarization operating modes while also having a harmonic suppression function, thereby improving anti-interference capability and reducing costs.

Description

Technical Field

[0001] The present invention relates to the field of radio ranging, in particular to a variable circular polarization device with harmonic suppression. Background Art

[0002] The rapid development of phased array technology in communications and radar systems has improved signal transmission quality and range, making RF transceiver systems more powerful and array configurations more flexible. However, as the scale of phased array systems continues to expand, the size, integration methods, hardware cost, anti-interference characteristics, and maneuverability of antenna and feed systems have also gained widespread attention in the industry. In particular, in the fields of satellite-based, airborne, and mobile measurement, the demand for intelligent, lightweight, and anti-interference features is becoming increasingly urgent. Compared to linear polarization, which is more susceptible to multipath and atmospheric refraction, circular polarization is less sensitive to interference signals and exhibits uniform transmission across space. To further enhance signal anti-interference capabilities and improve signal transmission quality in diverse environments, it is crucial to design a RF front-end device with variable circular polarization. This device, capable of switching between left-hand and right-hand circular polarization modes at different times, is crucial depending on system requirements.

[0003] See CN111786127A. In traditional circular polarization switching methods, whether it is a method of forming circular polarization by combining single-feed line polarization with rotating feed, or a method of achieving circular polarization switching by changing the phase difference between two feeds using dual feed, each method uses one active channel for each antenna polarization unit. This results in a large number of active channels, which is not conducive to lightweight product integration and also leads to hardware cost. See CN119050680B, which discloses a circular polarization switching phased array antenna and polarization switching method. By integrating a set of left-hand circular polarization and a set of right-hand circular polarization independent grid arrays, the circular polarization antenna polarization switching function is achieved by shutting down half of the active channels. Although only half of the active channels are in operation at the same time, which reduces power consumption, the shut-down active channels and their corresponding interconnected polarized antenna units still occupy a large amount of hardware resources, making the system less optimized in terms of volume and cost. Furthermore, current industry reports do not yet mention the technical means to simultaneously achieve circular polarization switching and suppress harmonics. However, harmonic suppression is increasingly being discussed in current communications and radar system engineering applications. The higher the harmonic suppression, the stronger the electromagnetic compatibility and anti-interference characteristics when complex, multiple systems operate simultaneously. Therefore, while considering the variable circular polarization operating regime, achieving harmonic suppression is undoubtedly a further improvement in system performance. Summary of the Invention

[0004] The present invention addresses the relatively high cost of existing technologies that utilize a single polarized antenna unit for a single active transceiver channel to receive or transmit radio frequency signals of different polarizations. The present invention proposes a variable circular polarization device with harmonic suppression. This device incorporates an absorptive polarization switch and Lange bridge cascade technology into the harmonic suppression variable circular polarization unit to switch between left-hand and right-hand circular polarization operating modes, thereby improving anti-interference capabilities while reducing costs. Furthermore, the introduction of harmonic suppression technology into the harmonic suppression variable circular polarization unit can suppress harmonic interference components, improving the system's electromagnetic compatibility and anti-interference characteristics.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A variable circular polarization device with a harmonic suppression function includes four groups of unit structures with identical structures and a four-channel amplitude and phase control multifunctional unit, wherein the four groups of unit structures are connected to the four-channel amplitude and phase control multifunctional unit in a parallel manner;

[0007] Each unit in the four-unit structure includes a harmonic suppression variable circular polarization unit and a transmit / receive amplification unit; the first / second port of the harmonic suppression variable circular polarization unit is respectively connected to the H / V polarization port of the corresponding external antenna unit, and the third port is connected to the common terminal of the transmit / receive amplification unit; the transmitting end and receiving end of the transmit / receiver amplification unit are respectively connected to the four corresponding channels of the four-channel amplitude and phase control multifunctional unit;

[0008] The four-channel amplitude and phase control multifunctional unit is used to realize signal synthesis and distribution, and is provided with a COM port, which is a global input / output port.

[0009] Furthermore, the harmonic suppression variable circular polarization unit includes a harmonic suppression polarization switch and a Lange bridge; the harmonic suppression polarization switch adopts an absorption type radio frequency three-port structure, and the three radio frequency ports are respectively a common port S1, a second port S2 and a third port S3; the Lange bridge adopts a radio frequency four-port structure, and the four radio frequency ports are respectively a first port P1, a second port P2, a third port P3 and a fourth port P4; the common port S1 of the harmonic suppression polarization switch is connected to the common end of the receiving and transmitting unit, the second port S2 is connected to the fourth port P4 of the Lange bridge, and the third port S3 is connected to the first port P1 of the Lange bridge. 1; the third port P3 of the Lange bridge is connected to the V1 polarization port of the external corresponding antenna, and the third port P2 of the Lange bridge is connected to the H1 polarization port of the external corresponding antenna; the second port P2 and the third port P3 of the Lange bridge are connected to a pair of external antenna polarization units; when the first port P1 inputs an RF signal and the fourth port P4 is connected to a matching load, equal amplitude +90° phase shift signal transmission is achieved between the second port P2 and the third port P3; when the fourth port P4 inputs an RF signal and the first port P1 is connected to a matching load, equal amplitude -90° phase shift signal transmission can be achieved between the second port P2 and the third port P3.

[0010] The variable circular polarization device with harmonic suppression function of the present invention has a harmonic suppression polarization switch and a Lange bridge integrated in its harmonic suppression variable circular polarization unit. The harmonic suppression switch is an absorption switch that adopts a radio frequency three-port structure. The coordination of the harmonic suppression switch and the Lange bridge realizes the switching of the working mode between left-hand circular polarization and right-hand circular polarization, improves the anti-interference ability and reduces the cost. By introducing an inductor structure connected in series with the gate port of the switch tube and a resonant matching network with an inductor and a capacitor in the harmonic suppression switch, the zero-point effect principle of the switch radio frequency transmission is changed to realize the harmonic suppression function. The suppression effect on the second harmonic is more obvious and is not affected by any polarization switching.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. In this variable circular polarization device, one active transceiver front end corresponds to a pair of polarized antenna units. Each active channel and polarized antenna unit operates at maximum capacity, eliminating any waste of hardware resources. Because the number of active channels is small, the device is both cost-effective and compact, achieving both low-cost and miniaturization of the phased array system.

[0013] 2. The present invention introduces the inductance at the control end of the switch tube into the harmonic suppression variable circular polarization unit to participate in the resonance and matching network as a compensation structure for harmonic suppression. At the same time, the inductor and capacitor network introduced in the RF branch has the harmonic suppression function while realizing the circular polarization switching function, thereby enhancing the anti-interference ability and electromagnetic compatibility adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a block diagram of a variable circular polarization device with harmonic suppression function according to the present invention;

[0015] Figure 2 This is a principle block diagram of the four-channel amplitude and phase control multifunctional unit of the present invention;

[0016] Figure 3 This is a block diagram of the principle of the large transmitting and receiving unit of the present invention;

[0017] Figure 4 This is a principle block diagram of the harmonic suppression variable circular polarization unit of the present invention;

[0018] Figure 5 This is a structural diagram of the harmonic suppression polarization switch circuit of the harmonic suppression variable circular polarization unit of the present invention;

[0019] Figure 6 This is a power transmission characteristic curve of a harmonic suppression variable circular polarization unit in an embodiment;

[0020] Figure 7 1 is a common port impedance matching characteristic curve of a harmonic suppression variable circular polarization unit in an embodiment;

[0021] Figure 8 The impedance matching characteristic curve of the harmonic suppression variable circular polarization unit and the connection port of the polarized antenna in the embodiment;

[0022] Figure 9 The figure is a block diagram comparing the existing implementation scheme of the circular polarization device with the scheme of the present invention. DETAILED DESCRIPTION

[0023] The following detailed description of the technical solution of the present invention is provided in conjunction with specific implementations. It should be noted that the following implementation is merely an example of the present invention and is not limited to a specific frequency band. Those skilled in the art should readily understand that any variable circular polarization device with harmonic suppression, whether a transceiver-integrated phased array system or a simple receiver or transmitter system, consistent with the technical approach of the present invention and proposed in accordance with the principles of the present invention, falls within the scope of protection of the present invention.

[0024] This embodiment provides a variable circular polarization device with a harmonic suppression function. It has bidirectional signal transmission capabilities, including receiving and transmitting (receiving and transmitting), and is capable of switching between left-hand circular polarization and right-hand circular polarization. In the left-hand circular polarization and right-hand circular polarization receiving modes, it has the ability to suppress harmonics of the received signal at the input port. In the left-hand circular polarization and right-hand circular polarization transmitting modes, it has the ability to suppress harmonics of the transmitted signal at the output port. The connection relationship, signal flow, and corresponding functions of each unit are described as follows:

[0025] like Figure 1 As shown, the variable circular polarization device with harmonic suppression function provided by this embodiment includes four groups of unit structures and a four-channel amplitude and phase control multifunctional unit;

[0026] The four groups of unit structures are respectively a first unit structure, a second unit structure, a third unit structure and a fourth unit structure.

[0027] The first unit structure consists of a harmonic suppression variable circular polarization unit A and a transmit / receive amplification unit A; the first port of the harmonic suppression variable circular polarization unit A is connected to the polarization port of the external first antenna H1, the second port is connected to the polarization port of the external first antenna V1, and the third port is connected to the common end of the transmit / receive amplification unit A; the common end of the transmit / receive amplification unit A is also the signal port X1, and the receiving port R1 and transmitting port T1 of the transmit / receive amplification unit A are connected to the first channel of the four-channel amplitude and phase control multifunctional unit.

[0028] The second unit structure consists of a harmonic suppression variable circular polarization unit B and a receiving and transmitting amplification unit B; the first port of the harmonic suppression variable circular polarization unit B is connected to the external second antenna H2 polarization port, the second port is connected to the external second antenna V2 polarization port, and the third port is connected to the common end of the receiving and transmitting amplification unit B; the common end of the receiving and transmitting amplification unit B is also the signal port X2, and the receiving port R2 and transmitting port T2 of the receiving and transmitting amplification unit B are connected to the second channel of the four-channel amplitude and phase control multifunctional unit.

[0029] The third unit structure consists of a harmonic suppression variable circular polarization unit C and a transmit / receive amplification unit C; the first port of the harmonic suppression variable circular polarization unit C is connected to the polarization port of the external third antenna H3, the second port is connected to the polarization port of the external third antenna V3, and the third port is connected to the common end of the transmit / receive amplification unit C; the common end of the transmit / receive amplification unit C is also the signal port X3, and the receiving port R3 and transmitting port T3 of the transmit / receive amplification unit C are connected to the third channel of the four-channel amplitude and phase control multifunctional unit.

[0030] The fourth unit structure consists of a harmonic suppression variable circular polarization unit D and a transmit / receive amplification unit D; the first port of the harmonic suppression variable circular polarization unit D is connected to the external fourth antenna H4 polarization port, the second port is connected to the external fourth antenna V4 polarization port, and the third port is connected to the common end of the transmit / receive amplification unit D; the common end of the transmit / receive amplification unit D is also the signal port X4, and the receiving port R4 and transmitting port T4 of the transmit / receive amplification unit D are connected to the fourth channel of the four-channel amplitude and phase control multifunctional unit.

[0031] The four-channel amplitude and phase control multifunctional unit is used to realize signal synthesis and distribution, and its COM port serves as a global input / output port.

[0032] In the transmitting mode, the signal is input from the COM port, passes through the four-channel amplitude and phase control multifunctional unit, the large receiving and transmitting unit, and the harmonic suppression variable circular polarization unit, and then passes through four pairs of polarized antennas H1 and V1, H2 and V2, H3 and V3, H4 and V4, and a total of eight ports radiate the output signal;

[0033] In receiving mode, the signal is input from the COM port, passes through the four-channel amplitude and phase control multifunctional unit, the receiving and transmitting large unit, and the harmonic suppression variable circular polarization unit, and then enters from four pairs of polarized antennas H1 and V1, H2 and V2, H3 and V3, H4 and V4, a total of eight ports, and is synthesized by the harmonic suppression variable circular polarization unit, the receiving and transmitting large unit, and the four-channel amplitude and phase control multifunctional unit before being output through the COM port.

[0034] The four unit structures of this embodiment are completely identical in structure and workflow. As the core component of the variable circular polarization device with harmonic suppression function, the circuit structure and principle of the first unit structure are described in detail by taking the first unit structure as an example.

[0035] In the first unit structure, the principle diagram of the harmonic suppression variable circular polarization unit is as follows Figure 4As shown, it includes a harmonic suppression polarization switch and a Lange bridge. The harmonic suppression variable circular polarization unit includes a harmonic suppression polarization switch and a Lange bridge. The harmonic suppression polarization switch adopts an absorptive RF three-port structure, with the three ports being a common port S1, a second port S2, and a third port S3. The Lange bridge adopts an RF four-port structure, with the four ports being a first port P1, a second port P2, a third port P3, and a fourth port P4. The common port S1 of the harmonic suppression polarization switch is connected to the common end of the receiving and transmitting amplifier unit, the second port S2 is connected to the fourth port P4 of the Lange bridge, and the third port S3 is connected to the first port P1 of the Lange bridge; the third port P3 of the Lange bridge is connected to the V1 polarization port of the external corresponding antenna, and the third port P2 of the Lange bridge is connected to the H1 polarization port of the external corresponding antenna; the second port P2 and the third port P3 of the Lange bridge are connected to an external pair of antenna polarization units; when the first port P1 inputs an RF signal and the fourth port P4 is connected to a matching load, equal amplitude +90° phase shift signal transmission is achieved between the second port P2 and the third port P3; when the fourth port P4 inputs an RF signal and the first port P1 is connected to a matching load, equal amplitude -90° phase shift signal transmission can be achieved between the second port P2 and the third port P3.

[0036] based on Figure 4 Based on the principle given, this embodiment provides a harmonic suppression polarization switch structure, such as Figure 5As shown, the harmonic suppression switch includes: a first RF branch, a second RF branch, a DC blocking capacitor C01 and a transmission line T01; the first RF branch includes: a transmission line TA1, a transmission line TA2, a transmission line TA3, a capacitor CA1, a capacitor CA2, a capacitor CA3, an inductor LA1, an inductor LA2, an inductor LA3, a resistor RA1, a resistor RA2, a resistor RA3, a switch tube MA1 and a switch tube MA2; wherein: one end of the transmission line TA1 is connected to one end of the transmission line T01, and the other end of the transmission line TA1 is connected to the drain of the switch tube MA1; the source of the switch tube MA1 is connected to one end of the inductor LA2 and one end of the transmission line TA2. The first and second ends of the switching transistor MA2 and MA3 are connected, and the gate is connected to the control signal port VC1 through the inductor LA1; the other end of the inductor LA2 is grounded through the capacitor CA1; the other end of the transmission line TA2 is connected to the drain of the switching transistor MA2 and one end of the transmission line TA3; the source of the switching transistor MA2 is connected to one end of the resistor RA2 and one end of the resistor RA3, and the gate is connected to the control signal port VC2 through RA1; the other end of the transmission line TA3 is connected to one end of the capacitor CA3 and one end of the inductor LA3; the other end of the resistor RA2 is connected to the other end of the inductor LA3 and the power supply VDD; the other end of the resistor RA3 is grounded through the capacitor CA2; and the other end of the capacitor CA3 is connected to the second port S2. The second RF branch is completely symmetrical with the first RF branch, and includes: transmission line TB1, transmission line TB2, transmission line TB3, capacitor CB1, capacitor CB2, capacitor CB3, inductor LB1, inductor LB2, inductor LB3, resistor RB1, resistor RB2, resistor RB3, switch tube MB1 and switch tube MB2; wherein: one end of transmission line TB1 is connected to one end of transmission line T01, and the other end of transmission line TB1 is connected to the drain of switch tube MB1; the source of switch tube MB1 is connected to one end of inductor LB2 and one end of transmission line TB2, and the gate is connected to control signal port VC2 via inductor LB1; The other end of inductor LB2 is grounded via capacitor CB1; the other end of transmission line TB2 is connected to the drain of switch MB2 and one end of transmission line TB3; the source of switch MB2 is connected to one end of resistor RB2 and one end of resistor RB3, and its gate is connected to control signal port VC1 via RB1; the other end of transmission line TB3 is connected to one end of capacitor CB3 and one end of inductor LB3; the other end of resistor RB2 is connected to the other end of inductor LB3 and power supply VDD; the other end of resistor RB3 is grounded via capacitor CB2; the other end of capacitor CB3 is connected to second port S3; the other end of transmission line T01 is connected to common port S1 via capacitor C01. Second port S2 and third port S3 are in reverse conduction state, that is, when second port S2 is conducting, third port S3 is off, and vice versa.

[0037] When the second port S2 is turned on and the third port S3 is turned off, the switch tubes MA1 and MB2 are in the on state, and the switch tubes MA2 and MB1 are in the off state; by introducing the inductor LA1 in series between the control signal port VC1 and the switch tube MA1, a new transmission zero point is introduced in the first RF branch that is turned on. The frequency response of the transmission zero point is related to the inductance value of the inductor LA1 and the parasitic capacitance of the switch tubes MA1 and MB2 in the on state. The resonant matching network composed of the inductor LA2 and the capacitor CA1 introduces another zero point. This zero point can form a suppression effect within a certain bandwidth of the harmonic frequency range with the aforementioned zero point by taking appropriate values ​​of the inductor LA2 and the capacitor CA1, while the second RF branch that is turned off is not affected.

[0038] The power supply VDD is a standard power supply voltage of +5V or +3.3V. It provides a DC bias potential for the source stages of the switches MA1, MA2, MB1, and MB2 through a feed network consisting of resistors RA2, RB2, inductor LA3, and LB3. Capacitors C01, CA1, CB1, CA2, and CB2 are isolation capacitors. The switch control signal ports VC1 and VC2 use positive voltage control logic of 0 / +5V or 0 / +3.3V. This eliminates the need to provide a negative power supply for the system, reducing system cost and complexity. Transmission lines T01, TA1, TA2, TA3, TB1, TB2, and TB3 are used to improve the impedance matching characteristics of the switching circuit, achieve better return loss, and optimize the insertion loss of the cascade connection between the switch and the Lange bridge; resistors RA3 and RB3 are load resistors, used to provide a 50-ohm load for the port in the off state to achieve good port standing wave and realize the absorptive effect of the switch, thereby ensuring that the Lange bridge can have a good load matching port.

[0039] The harmonic suppression polarization switch circuit described above was simulated and verified using an S-band 2.2-2.6 GHz measurement and control system as an application context. It should be noted that the harmonic suppression polarization switch circuit of this embodiment is not only applicable to the S-band; its circuit structure is also applicable to other operating frequency bands, including the K and Ka bands of satellite communications. When used in different frequency bands, the corresponding harmonic suppression function can be achieved by flexibly adjusting the values ​​of the inductor and capacitor based on the frequency suppression position required by the actual application band.

[0040] The receiving and sending large unit is as follows Figure 3 As shown, it includes a limiter, a low noise amplifier, a power amplifier and a first transceiver switch. The low noise amplifier corresponds to Figure 3 The low noise amplifier in the power amplifier corresponds to Figure 3 The first transceiver switch corresponds to the power amplifier Figure 3 The switch in the circuit. One end of the limiter is connected to one end of the low-noise amplifier, and the other end is connected to the signal port X1 via the first transceiver switching switch. The other end of the low-noise amplifier is connected to the receiving terminal R1 and the four-channel amplitude and phase control multifunctional unit. One end of the power amplifier is connected to the signal port X1 via the first transceiver switching switch, and the other end is connected to the transmitting port T1 and the four-channel amplitude and phase control multifunctional unit. The first transceiver switching switch is used to switch between two different operating modes: receiving and transmitting. The limiter provides overpower protection for the receiving circuit, and the gain characteristics of the low-noise amplifier can suppress noise in subsequent circuits. The power amplifier has high-efficiency output characteristics. The transceiver amplification unit can be integrated using GaAs or low-voltage GaN processes, or CMOS or SiGe processes. During implementation, the selection is based on the range requirements of the phased array system. When the transceiver amplification unit is integrated using GaAs or low-voltage GaN processes, it can be designed within the same integrated circuit as the harmonic suppression variable circular polarization unit. When the transceiver amplification unit is integrated using CMOS or SiGe processes, it can be designed within the same integrated circuit as the four-channel amplitude and phase control multifunctional unit.

[0041] The four-channel amplitude and phase control multifunctional unit is as follows Figure 2 As shown, it includes four transceiver channels and a power combining network. One end of the four transceiver channels is connected to the receiving and transmitting channels of the four transceiver amplifier units one by one, and the other end is connected to the power combining network. The four transceiver channels have the same structure. Each transceiver channel includes a second transceiver switching switch, a six-bit phase shifter, a first driver amplifier, a second driver amplifier and a six-bit attenuator. Figure 2 The switch in the middle; one end of the six-bit phase shifter is connected to the power combining network, and the other end is connected to the second transceiver switching switch to form a common branch of the transceiver channel; the first driver amplifier is connected to the second transceiver switching switch as a transmitting branch, and the other end is connected to the transmitting port of the corresponding large transceiver unit; one end of the six-bit attenuator is connected to one end of the second driver amplifier to form a receiving branch of the transceiver channel, the other end of the six-bit attenuator is connected to the second transceiver switching switch, and the other end of the second driver amplifier is connected to the receiving port of the corresponding large transceiver unit.

[0042] In this embodiment, the switching between receive and transmit operating modes is achieved by the second transceiver switch. In addition to switching between receive and transmit states, the second transceiver switch also switches between load states. A power combining network is used to implement transmit power splitting and receive power combining functions. COM is the signal common port of the four-channel amplitude and phase control multifunctional unit. The four-channel amplitude and phase control multifunctional unit integrates a serial-to-parallel conversion circuit, which connects to the control ports of internal circuits such as the six-bit attenuator, six-bit phase shifter, and the second transceiver switch. This circuit implements functions such as serial data distribution, transmission, loopback, and control, and generates control signals for controlling the harmonic suppression variable circular polarization unit and the transceiver amplification unit. A power modulation circuit is used to control the power on and off of the first and second driver amplifiers. The four-channel amplitude and phase control multifunctional unit is integrated using CMOS or SiGe technology; the six-bit attenuator has an attenuation range of 0~31.5dB and an attenuation step of 0.5dB; the six-phase shifter is located in the common branch of the four-channel amplitude and phase control multifunctional unit, with a phase shift range of 0~360° and a phase shift step of 5.625°; both the receiving branch and the transmitting branch contain a driving amplifier circuit for compensating the signal transmission gain; the serial-to-parallel conversion and power supply modulation circuits both use positive voltage control logic.

[0043] Figure 6 The power transmission characteristic curve of the harmonic suppression variable circular polarization unit of this embodiment is shown. Figure 6 S21 is the insertion loss. Figure 6 It can be seen that in the cascade state of the harmonic suppression polarization switch and Lange bridge, the insertion loss within the operating frequency band is less than 1.4dB, and its harmonic suppression reaches 20dB; compared with the structure in which the control port adopts a resistive structure and does not introduce an inductor-capacitor resonant matching network in the RF path, the harmonic suppression effect is obvious.

[0044] Figure 7 The common port impedance matching characteristic curve of the variable circular polarization unit for harmonic suppression in the embodiment is shown. Figure 7 S11 in the figure represents the return loss of the common port of the harmonic suppression variable circular polarization unit. Figure 7 It can be seen that the return loss is lower than -17dB within the working frequency band, achieving good port matching characteristics and ensuring good microwave signal transmission characteristics between the transmitting and receiving units.

[0045] Figure 8 The impedance matching characteristic curve of the harmonic suppression variable circular polarization unit and the polarized antenna connection port of this embodiment is shown. Figure 8 In the equation, S22 represents the return loss of the connection port between the harmonic suppression variable circular polarization unit and the antenna unit H, and S33 represents the return loss of the connection port between the harmonic suppression variable circular polarization unit and the antenna unit V. Figure 8It can be seen that the return losses of the two ports are both lower than -16dB within the operating frequency band, achieving good port matching characteristics and ensuring good microwave signal transmission characteristics between the antenna unit.

[0046] Figure 9 This is a block diagram comparing the existing implementation scheme of circular polarization device with the scheme of the present invention. Figure 9 It can be seen that in the existing schemes 1 and 2, a pair of polarized antenna units corresponds to two active channels, and the phase is adjusted by a phase shifter to achieve variable circular polarization. There is no measure for harmonic suppression between the phase shifter and the active channel. In the existing scheme 3, the antenna unit is first orthogonally fed, and then the switch between left-hand circular polarization and right-hand circular polarization is achieved by closing half of the active channels. On the surface, half of the active channels are saved, but in fact, the antenna units corresponding to the closed active channels are also in an inoperative state, which not only wastes hardware resources but also has a large size. There are no measures for harmonic suppression between the processing and the active channel; compared with the three existing schemes, although they can ultimately achieve the purpose of switching between left-hand circular polarization and right-hand circular polarization in the phased array, the present invention has a pair of polarized antenna units corresponding to two active channels, which not only saves hardware costs and power consumption and reduces heat dissipation pressure, but also realizes the harmonic suppression function in the harmonic suppression variable circular polarization unit by introducing an inductor-capacitor network in series with the inductor on the gate of the switch tube and the radio frequency branch, so that the implementation scheme of the present invention can take into account the advantages of low cost, high integration, strong anti-interference ability and strong electromagnetic compatibility adaptability.

[0047] From the above, it can be seen that the variable circular polarization device of this embodiment realizes the harmonic suppression function by connecting an inductor in series with the gate port of the switch tube inside the harmonic suppression variable circular polarization unit and introducing an inductor and capacitor into the switch RF branch, and utilizing the zero-point effect principle of changing the switch RF transmission, and has a significant effect on suppressing the second harmonic and is not affected by polarization switching. This solution not only reduces the number of active transceiver channels and saves hardware costs, but also achieves a good harmonic suppression function by introducing a harmonic suppression structure into the harmonic suppression variable circular polarization unit. Compared with the traditional solution of adding an additional filter to the system for harmonic suppression, the present invention integrates the harmonic suppression network into the branch of the harmonic suppression polarization switch, so that the system has a higher degree of integration and lower cost. In addition, the harmonic suppression function of the present invention can not only reduce the intermodulation components generated by the interference signal in the receiving state, but also suppress the harmonic signal components excited by the nonlinearity of the power amplifier itself in the transmitting state.

[0048] Finally, it should be noted that, during implementation, because the variable circular polarization device of this embodiment features strong electromagnetic compatibility, strong anti-interference capabilities, high integration, and low cost, multiple variable circular polarization devices of this embodiment can be combined to form a sub-array as part of a phased array system. Each unit within the device is suitable for integration using a single or multiple chips, ultimately implemented as a SiP (system-in-package) integration. The SiP can utilize ceramic or silicon-based packaging. However, those skilled in the art should understand that the present invention is not limited to the aforementioned SiP implementation; it can also utilize traditional microwave modules, three-dimensional stacked adapter plates, and other technical approaches. The core technical solution of this invention is to achieve low-cost, highly integrated variable circular polarization functionality while integrating an absorptive switch with internal harmonic suppression functionality. The invention also proposes a specific circuit structure implementation within the harmonic suppression variable circular polarization unit, which is not reported in conventional polarization implementations.

[0049] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A variable circular polarization device with harmonic suppression, characterized in that: It includes four groups of unit structures with identical structures and a four-channel amplitude and phase control multifunctional unit, and the four groups of unit structures are connected to the four-channel amplitude and phase control multifunctional unit in a parallel manner; Each unit in the four-unit structure includes a harmonic suppression variable circular polarization unit and a receiving and transmitting amplification unit; the first / second port of the harmonic suppression variable circular polarization unit is respectively connected to the H / V polarization port of the external corresponding antenna unit, and the third port is connected to the common end of the receiving and transmitting amplification unit; the harmonic suppression variable circular polarization unit includes a harmonic suppression polarization switch and a Lange bridge; the harmonic suppression polarization switch adopts an absorption RF three-port structure, and the three RF ports are respectively the common port S1, the second port S2 and the third port S3; the Lange bridge adopts an RF four-port structure, and the four RF ports are respectively the first port P1, the second port P2, the third port P3 and the fourth port P4; the common port S1 of the harmonic suppression polarization switch is connected to the common end of the receiving and transmitting amplification unit, and the second port S2 is connected to the fourth port P4 of the Lange bridge. The third port S3 is connected to the first port P1 of the Lange bridge; the third port P3 of the Lange bridge is connected to the V1 polarization port of the external corresponding antenna, and the third port P2 of the Lange bridge is connected to the H1 polarization port of the external corresponding antenna; the second port P2 and the third port P3 of the Lange bridge are connected to an external pair of antenna polarization units; when the first port P1 inputs an RF signal and the fourth port P4 is connected to a matching load, equal amplitude +90° phase shift signal transmission is achieved between the second port P2 and the third port P3; when the fourth port P4 inputs an RF signal and the first port P1 is connected to a matching load, equal amplitude -90° phase shift signal transmission can be achieved between the second port P2 and the third port P3; the transmitting end and the receiving end of the amplifying unit are respectively connected to the four corresponding channels of the four-channel amplitude and phase control multifunctional unit; The four-channel amplitude and phase control multifunctional unit is used to realize signal synthesis and distribution, and is provided with a COM port, which is a global input / output port.

2. The variable circular polarization device with harmonic suppression according to claim 1, characterized in that: The harmonic suppression polarization switch further includes: a first radio frequency branch, a second radio frequency branch, a DC blocking capacitor C01 and a transmission line T01; The first RF branch includes: transmission lines TA1, TA2, TA3, capacitors CA1, CA2, CA3, inductors LA1, LA2, LA3, resistors RA1, RA2, RA3, switches MA1, and MA2; wherein: One end of transmission line TA1 is connected to one end of transmission line T01, and the other end of transmission line TA1 is connected to the drain of switch tube MA1; the source of switch tube MA1 is connected to one end of inductor LA2 and one end of transmission line TA2; the other end of inductor LA2 is grounded via capacitor CA1; the other end of transmission line TA2 is connected to the drain of switch tube MA2 and one end of transmission line TA3; the source of switch tube MA2 is connected to one end of resistor RA2 and one end of resistor RA3, and the gate is connected to control signal port VC2 via RA1; the other end of transmission line TA3 is connected to one end of capacitor CA3 and one end of inductor LA3; the other end of resistor RA2 is connected to the other end of inductor LA3 and power supply VDD; resistor RA3 serves as a first matching load, and its other end is grounded via capacitor CA2; the other end of capacitor CA3 is connected to second port S2; The second RF branch includes: transmission line TB1, transmission line TB2, transmission line TB3, capacitor CB1, capacitor CB2, capacitor CB3, inductor LB1, inductor LB2, inductor LB3, resistor RB1, resistor RB2, resistor RB3, switch MB1 and switch MB2; wherein: One end of transmission line TB1 is connected to one end of transmission line T01, and the other end of transmission line TB1 is connected to the drain of switch tube MB1; the source of switch tube MB1 is connected to one end of inductor LB2 and one end of transmission line TB2; the other end of inductor LB2 is grounded via capacitor CB1; the other end of transmission line TB2 is connected to the drain of switch tube MB2 and one end of transmission line TB3; the source of switch tube MB2 is connected to one end of resistor RB2 and one end of resistor RB3, and the gate is connected to control signal port VC1 via RB1; the other end of transmission line TB3 is connected to one end of capacitor CB3 and one end of inductor LB3; the other end of resistor RB2 is connected to the other end of inductor LB3 and power supply VDD; resistor RB3 serves as a second matching load, and its other end is grounded via capacitor CB2; the other end of capacitor CB3 is connected to second port S3; the other end of transmission line T01 is connected to common port S1 via capacitor C01.

3. The variable circular polarization device with harmonic suppression according to claim 2, characterized in that: When the second port S2 is turned on and the third port S3 is turned off, the switch tubes MA1 and MB2 are in the on state, and the switch tubes MA2 and MB1 are in the off state; by introducing the inductor LA1 in series between the control signal port VC1 and the switch tube MA1, a new transmission zero point will be introduced on the first turned-on RF branch through the introduction of the inductor LA1. The frequency response of the transmission zero point is related to the inductance value of the inductor LA1 and the parasitic capacitance of the switch tubes MA1 and MB2 in the turned-on state. The resonant network composed of the inductor LA2 and the capacitor CA1 introduces another zero point. This zero point forms a suppression effect within the required bandwidth range of the harmonic frequency based on the values ​​of the inductor LA2 and the capacitor CA1 and the transmission zero point introduced on the first RF branch. The turned-off second RF branch is not affected.

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