Polarization cancellation network for improving polarization isolation of dual-polarized antenna and design method thereof
By coupling signals through the cross-polarization channels of a dual-polarized antenna and controlling their amplitude and phase, a polarization cancellation network is designed, which solves the problem of insufficient polarization isolation in the prior art and achieves effective polarization isolation improvement and communication performance improvement at different angles.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING INST OF SPACECRAFT SYST ENG
- Filing Date
- 2025-12-10
- Publication Date
- 2026-04-17
AI Technical Summary
Existing technologies struggle to effectively improve the polarization isolation of dual-polarized antennas, especially when the angle deviates from the axis, resulting in excessively high cross-polarization components that affect the polarization multiplexing performance of wireless communication.
By coupling a small portion of the signal through the cross-polarization channel of a dual-polarized antenna and controlling the amplitude and phase of the coupled signals to make them cancel each other out in space, a polarization cancellation network is designed to improve polarization isolation.
This technology effectively improves the polarization isolation of dual-polarized antennas at different angles, reduces cross-polarization interference, and enhances the polarization multiplexing performance of wireless communication.
Smart Images
Figure CN121887246A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a polarization cancellation network and its design method for improving the polarization isolation of dual-polarized antennas, belonging to the technical field of polarization multiplexing wireless communication systems. Background Technology
[0002] With the development of wireless communication technology and the expansion of wireless communication services, existing wireless spectrum resources are becoming increasingly scarce. Polarization multiplexing technology utilizes the polarization characteristics of electromagnetic waves to transmit signals using two orthogonally polarized electromagnetic waves, thereby doubling the spectrum utilization rate, making it an important means to improve spectrum utilization. The implementation of polarization multiplexing in wireless communication requires the use of dual-polarized antennas, and the polarization isolation of these antennas is a key indicator affecting the performance of wireless communication polarization multiplexing. If the cross-polarization component of one polarization channel has the same polarization characteristics as the main polarization component of another polarization channel, it will cause interference. If the polarization isolation is too low, the cross-polarization component will be too high, resulting in excessive interference to the other polarization channel and preventing normal communication in that channel. Therefore, improving the polarization isolation of the antenna is a key technology for wireless communication polarization multiplexing.
[0003] Currently, there are two main methods to improve antenna polarization isolation. One method is to strictly control the amplitude and phase of the two components of the excitation antenna, but this method leads to an overly intricate antenna structure, increasing the difficulty of manufacturing. The other method is to achieve cross-polarization cancellation by rotating and symmetrically arranging multiple antennas to improve polarization isolation. However, this method is only effective for cross-polarization cancellation along the antenna axis and has no effect on angles deviating from the axis; in fact, it may even worsen the polarization isolation. Summary of the Invention
[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a polarization cancellation network and its design method for improving the polarization isolation of dual-polarized antennas. A small part of the signal is coupled to the cross-polarization channel by coupling, and polarization cancellation is achieved by controlling the amplitude and phase of the coupled signal.
[0005] The technical solution of this invention is as follows: Firstly, a polarization cancellation network for improving the polarization isolation of a dual-polarized antenna includes two main channels connected to two ports of the dual-polarized antenna input terminal, respectively. The input signal enters the dual-polarized antenna through the main channel corresponding to the input port of the dual-polarized antenna, generating electromagnetic waves of the corresponding polarization, and simultaneously generating unwanted cross-polarized electromagnetic waves. Each main channel includes two directional couplers and two matching resistors. The matching resistors are connected in series with the corresponding main channel. One end of each directional coupler of each main channel is connected to the matching resistor, and the other end is connected to one of the directional couplers of the other main channel through a transmission line. The directional couplers are used to generate a coupling signal for the input signal and transmit it to the main channel corresponding to the other port through the transmission line, generating electromagnetic waves of the same polarization as the cross-polarized electromagnetic waves. By controlling the amplitude and phase of the coupling signal, the cross-polarized electromagnetic waves of the two ports have the same amplitude but opposite phase, thus canceling each other out.
[0006] Furthermore, the dual-polarized antenna is a dual-linearly polarized antenna or a dual-circularly polarized antenna.
[0007] Furthermore, the polarization cancellation network can be implemented in the form of a microstrip, a coaxial line, or a waveguide.
[0008] Furthermore, the coupling degrees C1 and C2 of the interconnected directional couplers satisfy C1 + C2 = 20lg( A 主 / A 交 ) ; A 主 , A 交 φ 主 φ 交 The amplitude, phase data of the main polarization and cross-polarization radiation fields.
[0009] Furthermore, A 主 , A 交 φ 主 φ 交 The data can be obtained from test data of the radiation pattern of a dual-polarized antenna or from simulation data of a dual-polarized antenna model.
[0010] Furthermore, the length of the transmission line between the interconnected directional couplers l 1. Satisfy the transmission line phase shift Φ( l 1)=φ 主 -φ 交 +180°; φ 主 φ 交 Phase data for dominant polarization and cross-polarization.
[0011] Secondly, a design method for a polarization cancellation network to improve the polarization isolation of a dual-polarized antenna is characterized by including: Step 1: Obtain the amplitude and phase data of the radiation fields of the two polarizations of the dual-polarized antenna. A 主 , φ 主 )and( A 交 ,φ 交 ); Step 2: Determine the polarization cancellation network parameters; Step 3: Design the polarization cancellation network based on the polarization cancellation network parameters; Step 4: Establish a joint simulation model of the dual-polarized antenna and the polarization cancellation network, and obtain the cross-polarization data of the antenna through simulation analysis; Step 5: Determine whether the antenna cross-polarization meets the specifications based on the cross-polarization data. If it does, the design is complete; otherwise, optimize the polarization cancellation network parameters and return to step 3.
[0012] Furthermore, the polarization cancellation network parameters include the coupling degree of the interconnected directional couplers and the length of the corresponding transmission lines.
[0013] Furthermore, the coupling degrees C1 and C2 of the interconnected directional couplers satisfy C1 + C2 = 20lg( A 主 / A 交 ) ; A 主 , A 交 φ 主 φ 交 The amplitude, phase data of the main polarization and cross-polarization radiation fields.
[0014] Furthermore, the length of the transmission line between the interconnected directional couplers l 1. Satisfy the transmission line phase shift Φ( l 1)=φ 主 -φ 交 +180°; φ 主 φ 交 Phase data for dominant polarization and cross-polarization.
[0015] The advantages of this invention compared to the prior art are: (1) The present invention couples the signal to the cross channel part through a coupling network, and controls the amplitude and phase of the coupled signal to reduce the cross polarization of the antenna and improve the polarization isolation of the antenna; (2) The polarization cancellation network of the present invention has two channels, each of which consists of a transmission line connecting two couplers. The amplitude of the coupled signal can be controlled by the coupler, and the phase of the coupled signal can be controlled by the transmission line, so as to achieve the cancellation of cross-polarized signals in space. Attached Figure Description
[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a block diagram illustrating the principle of the polarization cancellation network of this invention. Figure 2 The design flow of the polarization cancellation network for this invention is as follows. Detailed Implementation
[0017] To better understand the above technical solutions, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.
[0018] The following description, in conjunction with the accompanying drawings, provides a more detailed explanation of the polarization cancellation network and its design method for improving the polarization isolation of dual-polarized antennas, as provided in the embodiments of the present invention. Figure 1 The specific implementation may include: two main channels connected to the two ports of the dual-polarized antenna input terminal respectively. The input signal enters the dual-polarized antenna through the main channel corresponding to the input port of the dual-polarized antenna, generating electromagnetic waves of the corresponding polarization, and at the same time generating unwanted cross-polarized electromagnetic waves. Each main channel includes two directional couplers and two matching resistors. The matching resistors are connected in series with the corresponding main channel. One end of each directional coupler of each main channel is connected to the matching resistor, and the other end is connected to one of the directional couplers of the other main channel through a transmission line. The directional couplers are used to generate coupling signals of the input signal and transmit them to the main channel corresponding to the other port through the transmission line, generating electromagnetic waves of the same polarization as the cross-polarization. By controlling the amplitude and phase of the coupling signal, the cross-polarized electromagnetic waves of the two ports have the same amplitude and opposite phase, thus canceling each other out.
[0019] And design methods for polarization cancellation networks to improve the polarization isolation of dual-polarized antennas, such as Figure 2 It includes the following steps: Step 1: Obtain the amplitude and phase data of the radiation fields of the two polarizations of the dual-polarized antenna. A主 , φ 主 )and( A 交 ,φ 交 ); Step 2: Determine the polarization cancellation network parameters; Step 3: Design the polarization cancellation network based on the polarization cancellation network parameters; Step 4: Establish a joint simulation model of the dual-polarized antenna and the polarization cancellation network, and obtain the cross-polarization data of the antenna through simulation analysis; Step 5: Determine whether the antenna cross-polarization meets the specifications based on the cross-polarization data. If it does, the design is complete; otherwise, optimize the polarization cancellation network parameters and return to step 3.
[0020] In the solutions provided in the embodiments of the present invention, such as Figure 1 The antenna is a dual-polarized antenna, with its two input ports connected to the two output ports of the polarization cancellation network. The input signal from port 1 of the polarization cancellation network enters one polarization port (port 3) of the dual-polarized antenna via the main channel, forming a primary polarized electromagnetic wave in space, while also generating a smaller cross-polarized electromagnetic wave. The input signal from port 1 is coupled to port 4 of the polarization cancellation network via a coupling channel (composed of coupler 1 and coupler 2), and then enters the other polarization channel of the dual-polarized antenna, generating a cross-polarized electromagnetic wave in space. This cross-polarized electromagnetic wave cancels out the cross-polarized electromagnetic wave formed via the main channel, thereby improving the polarization isolation of the spatial electromagnetic wave formed by the input signal from port 1 through the dual-polarized antenna. The principle for improving the polarization isolation of the input signal from port 2 of the polarization cancellation network is the same as that of port 1.
[0021] First, a dual-polarized antenna is designed, which can be either a dual-linear polarized antenna or a dual-circular polarized antenna, with two input ports corresponding to the two polarizations respectively. Then, a polarization cancellation network is designed. The polarization cancellation network consists of four directional couplers and four matching resistors. The input signal of one main polarization is coupled out by a directional coupler, and the coupled signal is transmitted to the next directional coupler, then coupled into the cross-polarization channel, generating a specific cross-polarization component. This cross-polarization component cancels out the cross-polarization component generated by the main polarization channel in space, achieving polarization cancellation and improving polarization isolation. The amplitude and phase of the coupled signal depend on the amplitude and phase of the cross-polarization component to be canceled, which can be obtained through simulation or experimentation. In engineering implementation, this can be achieved by adjusting the coupling degree of the two directional couplers on each coupling channel and the length of the transmission line connecting the two directional couplers.
[0022] like Figure 2As shown, the specific design steps for improving the polarization isolation of a polarized antenna are as follows: Step 1: Obtain the amplitude and phase data of the radiation fields of the two polarizations of the dual-polarized antenna through simulation or actual measurement. A 主 , φ 主 )and( A 交 , φ 交 ); Step 2: Determine the coupling degrees C1 and C2 of the two directional couplers in the polarization cancellation network and the length of the transmission line according to the following principles. l 1: C1 + C2 = 20lg( A 主 / A 交 Transmission line phase shift Φ( l 1) =φ 主 -φ 交 +180° Step 3: Based on the polarization cancellation network parameters C1, C2 and l 1. Design a polarization cancellation network Step 4: Establish a joint simulation model of the dual-polarized antenna and the polarization cancellation network, and obtain the antenna's cross-polarization data through simulation analysis; Step 5: Determine if the antenna cross-polarization meets the specifications. If it does, the design is complete; otherwise, optimize the parameters C1, C2, and C3 of the polarization cancellation network. l 1. Then proceed to step 3.
[0023] The design steps for another cancellation branch in the polarization cancellation network are the same as described above.
[0024] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
[0025] The contents not described in detail in this specification are common knowledge to those skilled in the art.
Claims
1. A polarization cancellation network for improving the polarization isolation of a dual-polarized antenna, characterized in that, The system includes two main channels connected to the two input ports of a dual-polarized antenna. The input signal enters the dual-polarized antenna through the main channel corresponding to the input port, generating electromagnetic waves of the corresponding polarization, and simultaneously generating unwanted cross-polarized electromagnetic waves. Each main channel includes two directional couplers and two matching resistors. The matching resistors are connected in series with the corresponding main channel. One end of each directional coupler in each main channel is connected to the matching resistor, and the other end is connected to one of the directional couplers of the other main channel through a transmission line. The directional couplers are used to generate coupling signals for the input signal and transmit them to the main channel corresponding to the other port through the transmission line, generating electromagnetic waves with the same polarization as the cross-polarized electromagnetic waves. By controlling the amplitude and phase of the coupling signals, the cross-polarized electromagnetic waves at the two ports have the same amplitude but opposite phase, thus canceling each other out.
2. The polarization cancellation network for improving polarization isolation of a dual-polarized antenna according to claim 1, characterized in that, The dual-polarized antenna is either a dual-linearly polarized antenna or a dual-circularly polarized antenna.
3. The polarization cancellation network for improving polarization isolation of a dual-polarized antenna according to claim 1, characterized in that, The polarization cancellation network can be implemented in the form of a microstrip, a coaxial line, or a waveguide.
4. The polarization cancellation network for improving polarization isolation of a dual-polarized antenna according to claim 1, characterized in that, The coupling degrees C1 and C2 of the interconnected directional couplers satisfy C1 + C2 = 20lg( A 主 / A 交 ) ; A 主 , A 交 φ 主 φ 交 The amplitude, phase data of the main polarization and cross-polarization radiation fields.
5. The polarization cancellation network for improving polarization isolation of a dual-polarized antenna according to claim 4, characterized in that, A 主 , A 交 φ 主 φ 交 The data can be obtained from test data of the radiation pattern of a dual-polarized antenna or from simulation data of a dual-polarized antenna model.
6. The polarization cancellation network for improving polarization isolation of a dual-polarized antenna according to claim 1, characterized in that, The length of the transmission line between interconnected directional couplers l 1. Satisfy the transmission line phase shift Φ( l 1) =φ 主 -φ 交 +180°; φ 主 φ 交 Phase data for dominant polarization and cross-polarization.
7. A design method for a polarization cancellation network to improve the polarization isolation of a dual-polarized antenna, characterized in that, include: Step 1: Obtain the amplitude and phase data of the radiation fields of the two polarizations of the dual-polarized antenna. A 主 , φ 主 )and( A 交 , φ 交 ); Step 2: Determine the polarization cancellation network parameters; Step 3: Design the polarization cancellation network based on the polarization cancellation network parameters; Step 4: Establish a joint simulation model of the dual-polarized antenna and the polarization cancellation network, and obtain the cross-polarization data of the antenna through simulation analysis; Step 5: Determine whether the antenna cross-polarization meets the specifications based on the cross-polarization data. If it does, the design is complete; otherwise, optimize the polarization cancellation network parameters and return to step 3.
8. The design method according to claim 7, characterized in that, The polarization cancellation network parameters include the coupling degree of the interconnected directional couplers and the length of the corresponding transmission lines.
9. The design method according to claim 8, characterized in that, The coupling degrees C1 and C2 of the interconnected directional couplers satisfy C1 + C2 = 20lg( A 主 / A 交 ) ; A 主 , A 交 φ 主 φ 交 The amplitude, phase data of the main polarization and cross-polarization radiation fields.
10. The design method according to claim 8, characterized in that, The length of the transmission line between interconnected directional couplers l 1. Satisfy the transmission line phase shift Φ( l 1) =φ 主 -φ 交 +180°; φ 主 φ 交 Phase data for dominant polarization and cross-polarization.