Variable circular polarization device with harmonic suppression

Abstract

The invention relates to the field of radio distance measurement, in particular to a variable circular polarization device with harmonic suppression, which comprises four groups of unit structures and a four-channel amplitude-phase control multifunctional unit, and is characterized in that each group of unit in the four groups of unit structures comprises a harmonic suppression variable circular polarization unit and a receiving and transmitting amplification unit; a first port and a second port of the harmonic suppression variable circular polarization unit are respectively connected to H / V polarization ports of external corresponding antenna units, and a third port of the harmonic suppression variable circular polarization unit is connected with a common end of the receiving and transmitting amplification unit; the transmitting end and the receiving end of the receiving and transmitting amplification unit are respectively connected into four corresponding channels of the four-channel amplitude-phase control multifunctional unit; and the four-channel amplitude-phase control multifunctional unit is used for realizing signal synthesis and distribution. According to the invention, the harmonic suppression polarization switch is introduced into the harmonic suppression variable circular polarization unit to be in cascade connection with the Lange bridge, so that a harmonic suppression function is realized while the working modes of left-hand circular polarization and right-hand circular polarization are switched, the anti-interference capability is improved, and the cost is reduced.

Description

Technical Field

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

[0002] With the rapid development of phased array technology in the fields of communication and radar systems, the signal transmission quality and operating range have been improved, making the functions of radio frequency transceiver systems more powerful and the array mechanisms more flexible. However, with the continuous expansion of the scale of phased array systems, the volume, integration method, hardware cost, anti-interference characteristics, and mobility of their antenna-feeding systems have also received extensive attention in the industry. Especially in the satellite-borne field, airborne field, mobile measurement field, etc., the requirements for characteristics such as intelligence, lightweight, and anti-interference are more urgent. Compared with linear polarization, which is more susceptible to multipath effects and atmospheric refraction, circular polarization is less sensitive to interference signals and has the characteristic of uniform transmission in space. In order to further enhance the anti-interference ability of signals in different environmental conditions and improve the signal transmission quality, it is particularly important to design a radio frequency front-end device with variable circular polarization, that is, to achieve the working modes of left-handed circular polarization and right-handed circular polarization at different times by means of switch switching according to system requirements.

[0003] Referring to CN111786127A, in traditional circular polarization switching methods, whether it is the method of combining single-feed linear polarization with rotating feed to form circular polarization or the method of changing the phase difference between two feeds to achieve circular polarization switching, each active channel corresponds to one antenna polarization unit. The problem is that the number of active channels used is large, which is not conducive to the lightweight integration of products and also results in hardware cost consumption. Referring to CN119050680B, a circular polarization switching phased array antenna and a polarization switching method are disclosed. By integrating a set of left-handed circular polarization and a set of right-handed circular polarization independent grid arrays and closing half of the active channels, the polarization switching function of the circular polarization antenna is achieved. Although only half of the active channels are in the working state at the same time, reducing the power consumption, the closed active channels and their corresponding interconnected polarization antenna units still occupy a large amount of hardware resources, making the system not optimal in terms of volume and cost. In addition, there is currently no technical means in the current industry reports to suppress harmonics while achieving circular polarization switching. Harmonic suppression is mentioned more and more in current communication and radar system engineering applications. The higher the harmonic suppression, the stronger the electromagnetic compatibility adaptability and anti-interference characteristics when multiple complex systems work simultaneously. Therefore, being able to achieve harmonic suppression while considering the variable circular polarization working system undoubtedly further improves the system performance. Summary of the Invention

[0004] The object of the present invention is to address the problem of relatively high cost in the prior art where a single polarization antenna unit corresponds to a single active transceiver channel for receiving or transmitting radio frequency signals of different polarizations. A variable circular polarization device with harmonic suppression function is proposed. By introducing a cascading technology of an absorptive polarization switch and a Lange bridge in the harmonic suppression variable circular polarization unit, the switching between the left-handed circular polarization and right-handed circular polarization operating modes is achieved, while improving the anti-interference ability and reducing the cost. In addition, after introducing the harmonic suppression technology in the harmonic suppression variable circular polarization unit, the harmonic interference components can be suppressed, improving the electromagnetic compatibility characteristics and anti-interference characteristics of the system.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A variable circular polarization device with harmonic suppression function, comprising four sets of unit structures with exactly the same structure and a four-channel amplitude-phase control multi-functional unit. The four sets of unit structures are connected to the four-channel amplitude-phase control multi-functional unit in parallel; Each set of units in the four sets of unit structures includes a harmonic suppression variable circular polarization unit and a transceiver 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 end of the transceiver amplification unit; the transmitting end and receiving end of the transceiver amplification unit are respectively connected to four corresponding channels of the four-channel amplitude-phase control multi-functional unit; The four-channel amplitude-phase control multi-functional unit is used to realize the synthesis and distribution of signals, and it is provided with a COM port, which is a global input / output port.

[0006] Further, the harmonic suppression variable circular polarization unit includes a harmonic suppression polarization switch and a Lange coupler; the harmonic suppression polarization switch adopts an absorptive 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 coupler 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 transceiver amplification unit, the second port S2 is connected to the fourth port P4 of the Lange coupler, and the third port S3 is connected to the first port P1 of the Lange coupler; the third port P3 of the Lange coupler is connected to the V1 polarization port of the corresponding external antenna, and the second port P2 of the Lange coupler is connected to the H1 polarization port of the corresponding external antenna; the second port P2 and the third port P3 of the Lange coupler are connected to an external pair of antenna polarization units; when a radio frequency signal is input at the first port P1 and the fourth port P4 is connected to a matching load, equal-amplitude +90° phase-shifted signal transmission is achieved between the second port P2 and the third port P3, and when a radio frequency signal is input at the fourth port P4 and the first port P1 is connected to a matching load, equal-amplitude -90° phase-shifted signal transmission can be achieved between the second port P2 and the third port P3.

[0007] In the variable circular polarization device with harmonic suppression function of the present invention, a harmonic suppression polarization switch and a Lange coupler are integrated inside the harmonic suppression variable circular polarization unit. The harmonic suppression switch is an absorptive switch and adopts a radio frequency three-port structure. The cooperation between the harmonic suppression switch and the Lange coupler realizes the switching of the working mode between left-handed circular polarization and right-handed circular polarization, and improves the anti-interference ability and reduces the cost. By introducing an inductance structure in series with the gate terminal of the switching tube and a resonant matching network with inductance and capacitance in the harmonic suppression switch, the zero-point effect principle of the switch radio frequency transmission is changed to realize the harmonic suppression function, and the suppression effect on the second harmonic is obvious and not affected by any polarization switching.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In the variable circular polarization device of the present invention, one active transceiver front end corresponds to a pair of polarization antenna units, and each active channel and the polarization antenna unit are in the maximum available working state, without any waste of hardware resources. Since the number of active channels used is small, the cost is lower and the volume is smaller, realizing the low-cost and miniaturization of the phased array system.

[0009] 2. By introducing an inductor at the control end of the switching tube to participate in resonance and matching network in the harmonic suppression variable circular polarization unit of the present invention as a compensation structure for harmonic suppression, and at the same time introducing an inductance-capacitance network on the radio frequency branch, the harmonic suppression function is achieved while realizing the circular polarization switching function, thereby enhancing the anti-interference ability and electromagnetic compatibility adaptability. Description of the Drawings

[0010] Figure 1 It is a block diagram of a variable circular polarization device with harmonic suppression function according to the present invention; Figure 2 It is a principle block diagram of a four-channel amplitude-phase control multi-functional unit according to the present invention; Figure 3 It is a principle block diagram of a transceiver amplification unit according to the present invention; Figure 4 It is a principle block diagram of a harmonic suppression variable circular polarization unit according to the present invention; Figure 5 It is a circuit structure diagram of a harmonic suppression polarization switch of a harmonic suppression variable circular polarization unit according to the present invention; Figure 6 It is a power transmission characteristic curve of a harmonic suppression variable circular polarization unit in an embodiment; Figure 7 It is a common port impedance matching characteristic curve of a harmonic suppression variable circular polarization unit in an embodiment; Figure 8 It is an impedance matching characteristic curve of a connection port between a harmonic suppression variable circular polarization unit and a polarization antenna in an embodiment; Figure 9 It is a comparison block diagram between an existing implementation scheme of a circular polarization device and the scheme of the present invention. Detailed Embodiment

[0011] Next, in combination with the specific embodiments, the technical solutions of the present invention will be elaborated in detail. It should be noted that the following embodiments are only one example for explaining the technology of the present invention and are not limited to specific frequency bands. Those skilled in the art should easily understand that whether it is a transceiver integrated phased array system or a pure receiving system or a transmitting system, as long as it is consistent with the technical route of the present invention and a variable circular polarization device with harmonic suppression function proposed according to the idea of the present invention, it falls within the scope of protection of the present invention.

[0012] A variable circular polarization device with harmonic suppression function provided in this embodiment has the ability to transmit and receive (abbreviation: transceiver) two-way signals, has the ability to switch between left-handed circular polarization and right-handed circular polarization, has the ability to suppress harmonics of the received signal at the input port in the receiving mode working state of left-handed circular polarization and right-handed circular polarization, and has the ability to suppress harmonics of the transmitted signal at the output port in the transmitting mode working state of left-handed circular polarization and right-handed circular polarization. The connection relationship, signal flow direction, and corresponding functions of each unit are as follows: As Figure 1 shown, a variable circular polarization device with harmonic suppression function provided in this embodiment includes four groups of unit structures and a four-channel amplitude-phase control multi-functional unit; The four groups of unit structures are the first unit structure, the second unit structure, the third unit structure, and the fourth unit structure respectively. Among them: The first unit structure is composed of a harmonic suppression variable circular polarization unit A and a transceiver 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 transceiver amplification unit A; the common end of the transceiver amplification unit A is also the signal port X1, and the receiving port R1 and the transmitting port T1 of the transceiver amplification unit A are connected to the first channel of the four-channel amplitude-phase control multifunctional unit.

[0013] The second unit structure is composed of a harmonic suppression variable circular polarization unit B and a transceiver amplification unit B; the first port of the harmonic suppression variable circular polarization unit B is connected to the polarization port of the external second antenna H2, the second port is connected to the polarization port of the external second antenna V2, and the third port is connected to the common end of the transceiver amplification unit B; the common end of the transceiver amplification unit B is also the signal port X2, and the receiving port R2 and the transmitting port T2 of the transceiver amplification unit B are connected to the second channel of the four-channel amplitude-phase control multifunctional unit.

[0014] The third unit structure is composed of a harmonic suppression variable circular polarization unit C and a transceiver 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 transceiver amplification unit C; the common end of the transceiver amplification unit C is also the signal port X3, and the receiving port R3 and the transmitting port T3 of the transceiver amplification unit C are connected to the third channel of the four-channel amplitude-phase control multifunctional unit.

[0015] The fourth unit structure is composed of a harmonic suppression variable circular polarization unit D and a transceiver amplification unit D; the first port of the harmonic suppression variable circular polarization unit D is connected to the polarization port of the external fourth antenna H4, the second port is connected to the polarization port of the external fourth antenna V4, and the third port is connected to the common end of the transceiver amplification unit D; the common end of the transceiver amplification unit D is also the signal port X4, and the receiving port R4 and the transmitting port T4 of the transceiver amplification unit D are connected to the fourth channel of the four-channel amplitude-phase control multifunctional unit.

[0016] The four-channel amplitude-phase control multifunctional unit is used to realize the synthesis and distribution of signals, and its COM port serves as the global input / output port.

[0017] In the transmission mode, the signal is input from the COM port, and after passing through the four-channel amplitude-phase control multifunctional unit, the transceiver amplification unit, and the harmonic suppression variable circular polarization unit respectively, the signal is radiated and output through a total of eight ports of four pairs of polarized antennas H1 and V1, H2 and V2, H3 and V3, and H4 and V4; In the receiving mode, the signal is input from the COM port. After passing through the four-channel amplitude-phase control multifunctional unit, the transceiver amplifier unit, and the harmonic suppression variable circular polarization unit respectively, the signal enters through eight ports of four pairs of polarized antennas H1 and V1, H2 and V2, H3 and V3, and H4 and V4. After being synthesized by the harmonic suppression variable circular polarization unit, the transceiver amplifier unit, and the four-channel amplitude-phase control multifunctional unit, it is output through the COM port.

[0018] The four unit structures of this embodiment are exactly the same in structure and working process. As the core components of the variable circular polarization device with harmonic suppression function, taking the first unit structure as an example, its circuit structure and principle are described in detail.

[0019] In the first unit structure, the schematic diagram of the harmonic suppression variable circular polarization unit is as Figure 4 shown, including a harmonic suppression polarization switch and a Lange coupler. The harmonic suppression variable circular polarization unit includes a harmonic suppression polarization switch and a Lange coupler. The harmonic suppression polarization switch adopts an absorptive radio frequency three-port structure, and the three ports are the common port S1, the second port S2, and the third port S3 respectively. The Lange coupler adopts a radio frequency four-port structure, and the four ports are the first port P1, the second port P2, the third port P3, and the fourth port P4 respectively. The common port S1 of the harmonic suppression polarization switch is connected to the common end of the transceiver amplifier unit, the second port S2 is connected to the fourth port P4 of the Lange coupler, and the third port S3 is connected to the first port P1 of the Lange coupler; the third port P3 of the Lange coupler is connected to the V1 polarization port of the external corresponding antenna, and the second port P2 of the Lange coupler is connected to the H1 polarization port of the external corresponding antenna; the second port P2 and the third port P3 of the Lange coupler are connected to an external pair of antenna polarization units; when the radio frequency signal is input at the first port P1 and the fourth port P4 is connected to the matching load, an equal-amplitude +90° phase-shifted signal transmission can be achieved between the second port P2 and the third port P3. When the radio frequency signal is input at the fourth port P4 and the first port P1 is connected to the matching load, an equal-amplitude -90° phase-shifted signal transmission can be achieved between the second port P2 and the third port P3.

[0020] Based on Figure 4 the principle given, this embodiment gives the structure of the harmonic suppression polarization switch, as Figure 5As shown in the figure, 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: transmission lines TA1, TA2, TA3, capacitors CA1, CA2, CA3, inductors LA1, LA2, LA3, resistors RA1, RA2, RA3, switching transistors MA1 and MA2; where: 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 switching transistor MA1; the source of switching transistor MA1 is connected to one end of inductor LA2 and one end of transmission line TA2, and the gate is connected to the control signal port VC1 through inductor LA1; the other end of inductor LA2 is grounded through capacitor CA1; the other end of transmission line TA2 is connected to the drain of switching transistor MA2 and one end of transmission line TA3; the source of switching transistor MA2 is connected to one end of resistor RA2 and one end of resistor RA3, and the gate is connected to the control signal port VC2 through 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 the power supply VDD; the other end of resistor RA3 is grounded through capacitor CA2; the other end of capacitor CA3 is connected to the second port S2. The second RF branch has a completely symmetrical structure with the first RF branch, and this branch includes: transmission lines TB1, TB2, TB3, capacitors CB1, CB2, CB3, inductors LB1, LB2, LB3, resistors RB1, RB2, RB3, switching transistors MB1 and MB2; where: 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 switching transistor MB1; the source of switching transistor MB1 is connected to one end of inductor LB2 and one end of transmission line TB2, and the gate is connected to the control signal port VC2 through inductor LB1; the other end of inductor LB2 is grounded through capacitor CB1; the other end of transmission line TB2 is connected to the drain of switching transistor MB2 and one end of transmission line TB3; the source of switching transistor MB2 is connected to one end of resistor RB2 and one end of resistor RB3, and the gate is connected to the control signal port VC1 through 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 the power supply VDD; the other end of resistor RB3 is grounded through capacitor CB2; the other end of capacitor CB3 is connected to the third port S3; the other end of transmission line T01 is connected to the common port S1 through capacitor C01. The second port S2 and the third port S3 are in a reverse conduction state, that is, when the second port S2 is conducting, the third port S3 is cut off, and vice versa.

[0021] When the second port S2 is conducting and the third port S3 is cut off, the switching transistors MA1 and MB2 are in the conducting state, and the switching transistors MA2 and MB1 are in the cut-off state; by introducing an inductor LA1 in series between the control signal port VC1 and the switching transistor MA1, the introduction of the inductor LA1 will introduce a new transmission zero point on the conducting first radio frequency branch. The frequency response of the transmission zero point is related to the inductance value of the inductor LA1 and the parasitic capacitance in the conducting state of the switching transistors MA1 and MB2. The resonance matching network composed of the inductor LA2 and the capacitor CA1 introduces another zero point, and this zero point can form an inhibitory effect within a certain bandwidth in the harmonic frequency range with appropriate values of the inductor LA2 and the capacitor CA1, while the cut-off second radio frequency branch is not affected.

[0022] The power supply VDD is a standard power supply voltage of +5V or +3.3V. Through the feeding network composed of the resistors RA2, RB2, the inductors LA3 and LB3, a DC bias potential is provided for the sources of the switching transistors MA1, MA2, MB1 and MB2; the capacitors C01, CA1, CB1, CA2, CB2 are isolation capacitors, and the switching transistor control signal ports VC1 and VC2 are positive voltage control logics of 0 / +5V or 0 / +3.3V. The advantage is that there is no need to provide a negative power supply for the system, reducing the system usage cost and complexity. The transmission lines T01, TA1, TA2, TA3, TB1, TB2, TB3 are used to improve the impedance matching characteristics of the switching circuit, achieve better return loss, and at the same time can optimize the insertion loss of the cascade of the switch and the Lange bridge; the resistors RA3, RB3 are load resistors, which are used to provide a 50-ohm load for the port in the cut-off state to achieve good port standing wave, realize the absorption function of the switch, so as to ensure that the Lange bridge can have a good load matching port.

[0023] Taking the S-band 2.2 - 2.6GHz measurement and control system as the application background, the above-mentioned harmonic suppression polarization switch circuit is simulated and verified. It should be noted that the harmonic suppression polarization switch circuit of this embodiment is not only applicable to the S-band, but its circuit structure can also be applied to other operating frequency bands, including the K and Ka bands of satellite communication, etc. When applied in different frequency bands, it can flexibly adjust the values of inductors and capacitors according to the frequency suppression positions required by the actual application frequency band to achieve the corresponding harmonic suppression function.

[0024] The transmitting and receiving amplification unit is as Figure 3 shown, and includes a limiter, a low-noise amplifier, a power amplifier, and a first transmit-receive switching switch. Among them, the low-noise amplifier corresponds to Figure 3 the low-noise amplifier in Figure 3 and the power amplifier corresponds toFigure 3 The switch in Figure 3 . 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 through the first transceiver switch; the other end of the low-noise amplifier is the receiving end R1 and is connected to the four-channel amplitude-phase control multifunctional unit; one end of the power amplifier is connected to the signal port X1 through the first transceiver switch, and the other end is the transmitting port T1 and is connected to the four-channel amplitude-phase control multifunctional unit. The first transceiver switch is used to switch between two different operating modes of receiving and transmitting. The limiter has an over-power protection function for the receiving circuit, and the low-noise amplifier has a gain characteristic that can suppress the noise of the subsequent circuit. The power amplifier has a high-efficiency output characteristic. The transceiver amplifier unit can be integrated using GaAs or low-voltage GaN technology, or can be integrated using CMOS or SiGe technology. During implementation, it is selected according to the required operating range of the phased array system; when the transceiver amplifier unit is integrated using GaAs or low-voltage GaN technology, it can be designed in the same integrated circuit with the harmonic suppression variable circular polarization unit; when the transceiver amplifier unit is integrated using CMOS or SiGe technology, it can be designed in the same integrated circuit with the four-channel amplitude-phase control multifunctional unit.

[0025] The four-channel amplitude-phase control multifunctional unit is as Figure 2 shown, and includes four transceiver channels and a power combiner network. One end of the four transceiver channels is connected to the receiving and transmitting channels of the four transceiver amplifier units in a one-to-one correspondence, and the other end is connected to the power combiner network. The four transceiver channels have the same structure. Each transceiver channel includes a second transceiver switch, a six-bit phase shifter, a first driver amplifier, a second driver amplifier, and a six-bit attenuator, where the corresponding Figure 2 switch in Figure 2 ; one end of the six-bit phase shifter is connected to the power combiner network, and the other end is connected to the second transceiver switch, forming a common branch of the transceiver channel; the first driver amplifier serves as one end of the transmitting branch and is connected to the second transceiver switch, and the other end is connected to the transmitting port of the corresponding transceiver amplifier unit; one end of the six-bit attenuator is connected to one end of the second driver amplifier to form the receiving branch of the transceiver channel, the other end of the six-bit attenuator is connected to the second transceiver switch, and the other end of the second driver amplifier is connected to the receiving port of the corresponding transceiver amplifier unit.

[0026] In this embodiment, the switching between the receiving and transmitting operating modes is achieved by a second transceiver switching switch. In addition to the switching between the receiving and transmitting states, the second transceiver switching switch also has a load state switching function. The power combining network is used to implement the functions of power splitting in transmission and combining in reception. COM is the signal common port of the four-channel amplitude-phase control multi-functional unit; the four-channel amplitude-phase control multi-functional unit integrates a serial-parallel conversion circuit inside, which is connected to the control ports of internal circuits such as an internal six-bit attenuator, a six-bit phase shifter, and a second transceiver switching switch, to implement functions such as distribution, transmission, feedback, and control of serial data, and to generate control signals for controlling the harmonic suppression variable circular polarization unit and the transceiver amplifier unit; the power modulation circuit is used to control the power on and off of the first driver amplifier and the second driver amplifier. The four-channel amplitude-phase control multi-functional unit is integrated using CMOS or SiGe technology; the attenuation range of the six-bit attenuator is 0 to 31.5 dB, and the attenuation step is 0.5 dB; the six-bit phase shifter is in the common branch of the four-channel amplitude-phase control multi-functional unit, and the phase shift range is 0 to 360°, and the phase shift step is 5.625°; both the receiving branch and the transmitting branch include a driver amplifier circuit for compensating the signal transmission gain; both the serial-parallel conversion and the power modulation circuits use positive voltage control logic.

[0027] Figure 6 shows the power transmission characteristic curve of the harmonic suppression variable circular polarization unit of this embodiment, Figure 6 where S21 in it is the insertion loss. Refer to Figure 6 It can be seen that in the cascaded state of the harmonic suppression polarization switch and the Lange coupler, the insertion loss within the operating frequency band is lower than 1.4 dB, and its harmonic suppression reaches 20 dB; compared with the structure where the control port uses a resistor structure and no inductance-capacitance resonance matching network is introduced in the RF path, the effect of harmonic suppression is obvious.

[0028] Figure 7 shows the impedance matching characteristic curve of the common port of the harmonic suppression variable circular polarization unit of the embodiment, Figure 7 where S11 in it represents the return loss of the common port of the harmonic suppression variable circular polarization unit. From Figure 7 It can be seen that the return loss is lower than -17 dB within the operating frequency band, achieving good port matching characteristics and ensuring good microwave signal transmission characteristics between the transceiver amplifier unit.

[0029] Figure 8 shows the impedance matching characteristic curve of the connection port between the harmonic suppression variable circular polarization unit of this embodiment and the polarization antenna, Figure 8 where S22 in it 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. From Figure 8It can be seen that the return loss of both ports within the working frequency band is lower than -16 dB, achieving good port matching characteristics and ensuring good microwave signal transmission characteristics with the antenna unit.

[0030] Figure 9 It is a comparison block diagram of the existing implementation scheme of the circular polarization device and the scheme of the present invention. Refer to Figure 9 It can be seen that in both the existing Scheme 1 and Scheme 2, it is a way that a pair of polarization antenna units correspond to two active channels, and the phase shifter is used to adjust the phase to achieve variable circular polarization, and there are no measures for harmonic suppression between the phase shifter and the active channels; in the existing Scheme 3, first, orthogonal feeding is performed on the antenna unit, and then the switching between left-handed circular polarization and right-handed circular polarization is achieved by turning off half of the active channels. Apparently, half of the active channels are saved, but actually, the antenna units corresponding to the turned-off active channels are also in an inoperative state, which not only wastes hardware resources but also has a larger size, and there are no measures for harmonic suppression between the orthogonal feeding process and the active channels; compared with the three existing schemes, although the purpose of switching between left-handed circular polarization and right-handed circular polarization in the phased array can be finally achieved, the pair of polarization antenna units corresponding to two active channels in the present invention not only saves hardware costs, power consumption, and reduces the heat dissipation pressure, but also realizes the harmonic suppression function in the harmonic suppression variable circular polarization unit by connecting an inductor in series at the gate of the switching tube and introducing an inductor-capacitor network in the RF branch, making the implementable scheme of the present invention have the advantages of low cost, high integration, strong anti-interference ability, and strong electromagnetic compatibility adaptability.

[0031] In summary, for the variable circular polarization device of this embodiment, by connecting an inductor in series at the gate port of the switching tube inside the harmonic suppression variable circular polarization unit and introducing an inductor and a capacitor in the switching RF branch, the harmonic suppression function is realized by utilizing the principle of changing the zero-point effect of the switching RF transmission, and the suppression effect on the second harmonic is significant and not affected by polarization switching. This scheme not only reduces the number of active transceiver channels, saves hardware costs, but also realizes a good harmonic suppression function by introducing a harmonic suppression structure in the harmonic suppression variable circular polarization unit. Compared with the traditional scheme of adding an additional filter in the system for harmonic suppression, the present invention integrates the harmonic suppression network in the branch of the harmonic suppression polarization switch, making the system have higher integration and lower cost. In addition, the harmonic suppression function of the present invention can not only reduce the intermodulation components generated by interference signals in the receiving state, but also suppress the harmonic signal components excited by the nonlinearity of the power amplifier itself in the transmitting state.

[0032] Finally, it should be noted that during implementation, since the variable circular polarization device of this embodiment has the characteristics of strong electromagnetic compatibility adaptability, strong anti-interference ability, high integration, and low cost, multiple variable circular polarization devices of this embodiment can be spliced to form a sub-array and used as part of a phased array system. Each unit inside it is suitable for being integrated in the form of a single or multiple chips and finally realized in the form of SiP (system-in-package) integration. SiP can adopt ceramic-based and silicon-based packaging forms. However, those skilled in the art should understand that the present invention is not limited to the above SiP implementation method, and its implementation method can adopt traditional microwave modules, three-dimensional stacked interposer and other technical means. On the basis of realizing the low-cost and high-integration variable circular polarization function with the core value technical solution of the present invention, an absorption switch with harmonic suppression function is integrated inside, and a specific circuit structure implementation method inside the harmonic suppression variable circular polarization unit is proposed, and there is no technical report on harmonic suppression in the polarization methods realized by traditional solutions.

[0033] The above embodiments are only illustrative of the principles and effects of the present invention and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still 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 sets of unit structures with exactly the same structure and a four-channel amplitude-phase control multifunctional unit. The four sets of unit structures are connected to the four-channel amplitude-phase control multifunctional unit in parallel; Each set of units in the four sets of unit structures includes a harmonic suppression variable circular polarization unit and a transceiver amplifier unit; the first / second ports of the harmonic suppression variable circular polarization unit are respectively connected to the H / V polarization ports of the corresponding external antenna units, and the third port is connected to the common end of the transceiver amplifier unit; the transmitting end and the receiving end of the transceiver amplifier unit are respectively connected to four corresponding channels of the four-channel amplitude-phase control multifunctional unit; The four-channel amplitude-phase control multifunctional unit is used to realize signal synthesis and distribution, and it 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, wherein: The harmonic suppression variable circular polarization unit includes a harmonic suppression polarization switch and a Lange coupler; the harmonic suppression polarization switch adopts an absorptive 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 coupler 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 transceiver amplifier unit, the second port S2 is connected to the fourth port P4 of the Lange coupler, and the third port S3 is connected to the first port P1 of the Lange coupler; the third port P3 of the Lange coupler is connected to the V1 polarization port of the corresponding external antenna, and the second port P2 of the Lange coupler is connected to the H1 polarization port of the corresponding external antenna; the second port P2 and the third port P3 of the Lange coupler are connected to an external pair of antenna polarization units; when a radio frequency signal is input at the first port P1 and the fourth port P4 is connected to a matching load, an equal-amplitude +90° phase-shifted signal transmission can be realized between the second port P2 and the third port P3, and when a radio frequency signal is input at the fourth port P4 and the first port P1 is connected to a matching load, an equal-amplitude -90° phase-shifted signal transmission can be realized between the second port P2 and the third port P3.

3. A variable circular polarization device with harmonic suppression according to claim 2, 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 radio frequency 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 switching transistor MA1, and a switching transistor MA2; where: 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 switching transistor MA1; the source of switching transistor MA1 is connected to one end of inductor LA2 and one end of transmission line TA2; the other end of inductor LA2 is grounded through capacitor CA1; the other end of transmission line TA2 is connected to the drain of switching transistor MA2 and one end of transmission line TA3; the source of switching transistor 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 through 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 is the first matching load, and its other end is grounded through capacitor CA2; the other end of capacitor CA3 is connected to the 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, switching transistor MB1 and switching transistor MB2; where: 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 switching transistor MB1; the source of switching transistor MB1 is connected to one end of inductor LB2 and one end of transmission line TB2; the other end of inductor LB2 is grounded through capacitor CB1; the other end of transmission line TB2 is connected to the drain of switching transistor MB2 and one end of transmission line TB3; the source of switching transistor 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 through 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 is the second matching load, and its other end is grounded through capacitor CB2; the other end of capacitor CB3 is connected to the second port S3; the other end of transmission line T01 is connected to the common port S1 through capacitor C01.

4. A variable circular polarization device with harmonic suppression according to claim 3, characterized in that, When the second port S2 is conducting and the third port S3 is non-conducting, switching transistors MA1 and MB2 are in the conducting state, and switching transistors MA2 and MB1 are in the non-conducting state; by serially introducing inductor LA1 between the control signal port VC1 and switching transistor MA1, the introduction of inductor LA1 will introduce a new transmission zero on the conducting first RF branch. The frequency response of the transmission zero is related to the inductance value of inductor LA1 and the parasitic capacitance in the conducting state of switching transistors MA1 and MB2. The resonant network composed of inductor LA2 and capacitor CA1 introduces another zero, and this zero forms an inhibitory effect within the harmonic frequency required bandwidth range with the transmission zero introduced on the first RF branch according to the values of inductor LA2 and capacitor CA1, while the non-conducting second RF branch is not affected.

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