A method and system for dynamic compensation of axial ratio of circular polarization of an antenna
By generating a compensation signal on the cross-polarization channel with the same amplitude but opposite phase as the cross-polarization component of the main polarization channel, and then synthesizing it to suppress the cross-polarization component, the problem of axial ratio performance degradation of circularly polarized antennas under all-directional angles is solved, dynamic compensation for low axial ratio is achieved, system design is simplified and cost is reduced.
Patent Information
- Application Number
- CN202610861543.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-15
- Publication Date
- 2026-11-03
AI Technical Summary
Existing technologies struggle to achieve low axial ratio performance for circularly polarized antennas across all omnidirectional angles. In particular, the axial ratio performance deteriorates significantly during beam scanning, impacting antenna network access and transmit power usage.
By generating a compensation signal on the cross-polarization channel with the same amplitude but opposite phase as the cross-polarization component of the main polarization channel, and then combining it with the main polarization channel signal, the cross-polarization component is suppressed, the main polarization purity is improved, and dynamic compensation of axial ratio performance is achieved.
It improves axial ratio performance across all pointing angles, simplifies system architecture, is applicable to dual-linear polarization arrays and dual-circular polarization arrays, has good compatibility, and reduces hardware cost and complexity.
Smart Images
Figure CN123034136A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of antenna technology, and more specifically, to a method and system for dynamic compensation of the circular polarization axial ratio of an antenna. Background Technology
[0002] In satellite communications, to fully utilize spectrum and orbital resources, communication antennas often require high polarization isolation to ensure that neighboring satellites are not interfered with. For circularly polarized antennas, the axial ratio must be as small as possible. Existing methods to improve the polarization axial ratio include using antenna elements with high polarization purity and employing rotating arrays. These methods have significant effects on the antenna array normal, but achieving the required axial ratio across all angles and operating frequency bands is extremely difficult.
[0003] In satellite communication network access standards, specific requirements are generally set for the axial ratio under the pointing angle. Failure to meet these requirements will affect antenna network access or necessitate reducing transmission power. Therefore, there is an urgent need for a method that can dynamically compensate for the circular polarization axial ratio under all pointing angles to solve the problem of deterioration in the pointing axial ratio in existing technologies.
[0004] In response, this invention proposes a dynamic compensation method for the axial ratio of antenna circular polarization. Summary of the Invention
[0005] This invention provides a method and system for dynamic compensation of the axial ratio of circular polarization in antennas, aiming to solve the problem of performance degradation in axial ratio of existing circularly polarized antennas at different pointing angles during beam scanning, and to achieve low axial ratio operation at all pointing angles. The circularly polarized signal transmitted by the antenna can be regarded as a synthesis of two linearly polarized signals. When the amplitudes of the two linearly polarized components are equal and their phases differ by 90 degrees, it is an ideal circularly polarized signal with an axial ratio of 0dB. From the perspective of orthogonal decomposition, the circularly polarized signal can also be regarded as composed of left-hand circular polarization and right-hand circular polarization, and the axial ratio value reflects the level of the cross-polarization component.
[0006] This invention introduces a compensation signal with the same amplitude but opposite phase as the existing cross-polarization component of the antenna, and synthesizes this compensation signal with the original signal in the main polarization channel, thereby suppressing the cross-polarization component in the main polarization channel, improving the main polarization purity, and achieving the purpose of improving the axial ratio performance.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, this application provides a method for dynamic compensation of the axial ratio of an antenna circular polarization, including: Obtain the amplitude and phase characteristics of the cross-polarization components in the main polarization channel of the antenna at the target pointing angle; Based on the amplitude and phase characteristics, a compensation signal is generated on the cross-polarization channel of the antenna, and the compensation signal has the same amplitude and opposite phase to the cross-polarization component. The compensation signal is combined with the signal of the main polarization channel to obtain the compensated circularly polarized output signal; wherein the cross-polarization component in the circularly polarized output signal is suppressed.
[0008] Furthermore, the compensation signal is generated by adjusting the compensation phase shifter and compensation attenuator provided on the cross-polarization channel.
[0009] Furthermore, the amplitude and phase characteristics of the cross-polarization components in the main polarization channel are obtained by directly measuring the cross-polarization components of the main polarization channel at the target pointing angle; or by measuring the axial ratio of the antenna at the target pointing angle and iteratively adjusting the compensation signal until the axial ratio meets the preset index.
[0010] Furthermore, the method also includes: pre-calibrating the correspondence between the beam pointing angle and the compensation signal, and dynamically calling the corresponding compensation signal according to the current pointing angle when the antenna is working.
[0011] Furthermore, the main polarization channel and the cross polarization channel share the same pointing phase shifter to ensure that their beam pointing is consistent.
[0012] Furthermore, the antenna is a dual-linear polarized array antenna or a dual-circular polarized array antenna.
[0013] Furthermore, the signals from the main polarization channel and the cross-polarization channel are combined or separated by a coupler.
[0014] A dynamic compensation system for the axial ratio of an antenna circular polarization, applied in the above method, the system comprising: An array antenna is used to receive or transmit circularly polarized signals. A pointing phase shifter is used to control the beam pointing. The power supply network is used for signal synthesis or excitation of each channel of the antenna. A compensation phase shifter and a compensation attenuator are disposed on the cross-polarization channel to generate the compensation signal; A synthesizer is used to synthesize the compensation signal with the signal of the main polarization channel.
[0015] Furthermore, the power supply network includes a 90-degree bridge or a circularly polarized power supply network.
[0016] Furthermore, all radiation channels of the array antenna share the same set of compensation values from the compensation phase shifter and compensation attenuator.
[0017] The beneficial effects of this invention are as follows: Full-angle coverage: By dynamically adjusting, the axial ratio performance is improved at all pointing angles, solving the problem of axial ratio degradation during beam scanning in existing technologies.
[0018] Simple to implement: All channel amplitude compensation values and phase compensation values can use a unified compensation value, without the need for independent control of each antenna element, resulting in a simple and efficient system architecture.
[0019] Good compatibility: It is suitable for both dual-linear polarization array and dual-circular polarization array antenna architectures, and has good versatility.
[0020] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description
[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is a schematic diagram of the method steps of the present invention; Figure 2 This is a schematic diagram of the compensation system for the dual-polarized array antenna of the present invention; Figure 3 This is a schematic diagram of the compensation system for the dual circularly polarized array antenna of the present invention. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0024] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0025] Example 1: See Figure 1 This embodiment provides a method for dynamic compensation of the circular polarization axial ratio of an antenna.
[0026] S1. Obtain the amplitude and phase characteristics of the cross-polarization components in the main polarization channel of the antenna at the target pointing angle; Specifically, when the antenna beam is pointed at a target angle, due to factors such as the radiation characteristics of the array elements, mutual coupling effects, and array layout, cross-polarization components will inevitably be generated in the main polarization channel (i.e., the path through which circularly polarized signals are to be received or transmitted). The amplitude and phase of these cross-polarization components change with the pointing angle. This step obtains the amplitude value A and phase value of these cross-polarization components through measurement or calculation. .
[0027] S2. Based on the amplitude and phase characteristics, generate a compensation signal on the cross-polarization channel of the antenna, and make the amplitude of the compensation signal equal to that of the cross-polarization component but opposite in phase. Specifically, in obtaining the amplitude value A and phase value of the cross-polarization component Then, the system generates a compensation signal on a specially designed cross-polarization channel. The amplitude of this signal is adjusted to A, and the phase is adjusted to... (That is, out of phase with the cross-polarization component).
[0028] S3. The compensation signal is combined with the signal of the main polarization channel to obtain the compensated circular polarization output signal; wherein the cross-polarization component in the circular polarization output signal is suppressed; Specifically, after the compensation signal is superimposed on the original signal that originally contained cross-polarization components in the main polarization channel, since the two signals have equal amplitudes and opposite phases, the cross-polarization components in the original signal are effectively eliminated, and only the desired main polarization components are retained in the output signal, thereby achieving dynamic compensation of the axial ratio.
[0029] In some preferred embodiments, the compensation signal is generated by adjusting the compensation phase shifter and compensation attenuator disposed on the cross-polarization channel. The compensation phase shifter is used to adjust the phase, and the compensation attenuator is used to adjust the amplitude. The two are controlled independently, which can realize a compensation signal with arbitrary amplitude ratio and phase difference.
[0030] This embodiment employs phase shifters and attenuators, which offer fast response, high precision, and easy interface with digital control systems, facilitating dynamic real-time adjustment. Furthermore, both phase shifters and attenuators are mature RF front-end devices, offering low cost and high reliability.
[0031] In some preferred embodiments, the amplitude and phase characteristics of the cross-polarization components in the main polarization channel are obtained in two ways: The first method is to directly measure the cross-polarization component of the main polarization channel at the target pointing angle; for example, by using a vector network analyzer or polarization measurement equipment, the antenna is scanned at all angles in an anechoic environment, and the amplitude and phase values of the cross-polarization component in the main polarization channel at each angle are recorded to form a lookup table.
[0032] The second method involves measuring the axial ratio of the antenna at the target pointing angle and iteratively adjusting the compensation signal until the axial ratio meets a preset target. That is, instead of directly measuring the cross-polarization component, the final axial ratio is used as feedback to gradually approach the optimal compensation value.
[0033] Furthermore, the method also includes: pre-calibrating the correspondence between the beam pointing angle and the compensation signal, and dynamically calling the corresponding compensation signal according to the current pointing angle when the antenna is working; specifically, the antenna is scanned at all angles in an anechoic chamber, and the compensation phase shifter value and compensation attenuator value that optimize the axial ratio are recorded for each beam pointing angle, forming an angle-compensation value mapping table and storing it in the control unit. When the antenna is actually working, the control unit directly looks up the corresponding compensation value in the table according to the current beam pointing angle, without the need for real-time iterative calculation.
[0034] By pre-calibrating the correspondence between the beam pointing angle and the compensation signal, a correspondence table is constructed. The table lookup method has a fast response speed and is suitable for fast beam scanning scenarios of phased array antennas. At the same time, it reduces the computing power requirements for real-time calculations, making it easy to implement in embedded systems. In addition, the calibration process only needs to be performed once, and subsequent use does not require repeated measurements.
[0035] Furthermore, the main polarization channel and the cross-polarization channel share the same pointing phase shifter to ensure consistent beam pointing. Specifically, the pointing phase shifter is positioned before the 90-degree bridge (or circular polarization feed network) on the common path of the two channels. Therefore, the main polarization signal and the compensation signal experience the same phase delay, resulting in identical beam pointing. Sharing the pointing phase shifter physically guarantees beam pointing consistency, eliminating the need for additional calibration or synchronization control and simplifying system design. It also saves one pointing phase shifter, reducing hardware costs.
[0036] Furthermore, the antenna is a dual-linear polarization array antenna or a dual-circular polarization array antenna. The dual-linear polarization array needs to be used with a 90-degree bridge to generate circular polarization components; the dual-circular polarization array can directly output left-handed / right-handed circular polarization signals.
[0037] Furthermore, the signals from the main polarization channel and the cross-polarization channel are combined or separated using a coupler. The coupler is directional and can effectively isolate mutual interference between the two signals.
[0038] Example 2: like Figure 2 As shown, the antenna circular polarization axial ratio dynamic compensation system of this embodiment includes: Dual-polarized array: An array composed of dual-polarized units, each of which can independently receive or transmit two orthogonal linear polarization components; Pointer phase shifter: Located on the common path, used to control beam pointing; The power supply network includes a 90-degree bridge that converts bilinear polarized signals into a circular polarized main polarization channel and a cross-polarization channel. Compensation phase shifter and compensation attenuator: disposed on the cross-polarization channel, used to generate compensation signal; Synthesizer (i.e. coupler): Used to synthesize or separate the compensation signal from the signal of the main polarization channel.
[0039] The dual-polarized signal output from the dual-polarized array is passed through a 90-degree bridge to form two orthogonal circular polarization components: one is the main polarization channel, and the other is a cross-polarization channel (used to generate a compensation signal). It should be noted that a certain amount of cross-polarization component will inevitably be mixed into the main polarization channel, which is precisely what this invention aims to suppress.
[0040] The pointing phase shifter is located on the common path of the main polarization channel and the cross-polarization channel, and is shared by both. The pointing of the antenna beam is controlled by adjusting the pointing phase shifter. Since the main polarization channel and the cross-polarization channel share the same pointing phase shifter, the beam pointing of both is always consistent.
[0041] During operation, in transmit mode: the circularly polarized signal to be transmitted passes through a pointing phase shifter and enters a 90-degree bridge, where it is decomposed into two orthogonal linearly polarized components and fed into the dual-linearly polarized array. Simultaneously, based on the current pointing angle, a compensation phase shifter and a compensation attenuator generate a compensation signal on the cross-polarization channel. This compensation signal is sent to the dual-linearly polarized array via the cross-polarization channel and spatially superimposed on the main polarization signal, thereby suppressing cross-polarized radiation in the radiation field.
[0042] In receive mode, the dual-polarized signals received by the antenna array are combined into a circularly polarized signal via a 90-degree bridge. The signal in the main polarization channel contains the desired main polarization component and interfering cross-polarization components. The compensation channel generates an inverted signal based on a pre-calibrated compensation value, which is then superimposed on the main channel signal via a coupler to eliminate the cross-polarization components before being output.
[0043] Suppose that at a certain pointing angle, the cross-polarization component existing in the main polarization channel is: Where A is the amplitude. This represents the phase value. By adjusting the compensation phase shifter and compensation attenuator set on the cross-polarization channel, the compensation signal output by the cross-polarization channel is made into the desired value. That is, the amplitude of the compensation signal is equal to the amplitude of the cross-polarization component, but opposite in phase.
[0044] In receive mode, the compensated signal and the original signal in the main polarization channel are combined in the circuit via a coupler, effectively suppressing the cross-polarization components in the main polarization channel and obtaining a compensated circularly polarized output signal. In transmit mode, the compensated signal and the main polarization signal are superimposed in space after being radiated by the array, similarly suppressing the cross-polarization components. After the above compensation, at the target pointing angle, only the main polarization component is retained in the output signal, thereby improving the axial ratio.
[0045] Each pointing angle corresponds to a set of amplitude compensation values and phase compensation values. This correspondence can be obtained through pre-calibration: measuring the cross-polarization components in the main polarization channel at different pointing angles, determining and storing the compensation values according to the principle of "equal amplitude and opposite phase". During actual antenna operation, the corresponding compensation values are dynamically called according to the current pointing angle to achieve axial ratio performance improvement under all pointing conditions.
[0046] As an alternative, the amplitude compensation value and phase compensation value can also be obtained by measuring the antenna axis ratio in real time at the target pointing angle, iteratively adjusting the compensation phase shifter and compensation attenuator until the axis ratio meets the preset index, and the compensation value at this time is the required value.
[0047] In this embodiment, by changing the port configuration of the 90-degree bridge, the switching between left-hand circular polarization and right-hand circular polarization can be easily achieved without changing the array structure. At the same time, the cross-polarization component of the dual-line polarization array has a strong regularity with the scanning angle. Through pre-calibration, an accurate compensation model can be established, and it can still maintain excellent axial ratio performance under large-angle scanning (such as ±60°).
[0048] Example 3: like Figure 3 As shown, the antenna circular polarization axial ratio dynamic compensation system of this embodiment includes: Array antenna: An array composed of dual circularly polarized elements, each element of which can directly receive or transmit left-hand circularly polarized (LHCP) and right-hand circularly polarized (RHCP) signals; Pointer phase shifter: Located on the common path, used to control beam pointing; Power supply network: Directly outputs the main circular polarization channel and the cross polarization channel (no 90-degree bridge required). Compensation phase shifter and compensation attenuator: disposed on the cross-polarization channel, used to generate compensation signal; Synthesizer (i.e. coupler): Used to synthesize or separate the compensation signal from the signal of the main polarization channel.
[0049] The basic workflow of this embodiment is the same as that of Embodiment 2, except that the 90-degree bridge is omitted. The signal output by the antenna array is directly in circular polarization form: the main polarization channel outputs the desired circular polarization signal (such as left-hand circular polarization), and the cross-polarization channel outputs orthogonal circular polarization signals (such as right-hand circular polarization). The compensation signal is generated on the cross-polarization channel and coupled and superimposed with the signal from the main polarization channel to form the final signal.
[0050] All radiation channels of the array antenna share the same set of compensated phase shifters and compensated attenuators. This is because the distribution of cross-polarization components is uniform, and a uniform compensation value can be used to improve the axial ratio performance of the entire channel without the need for independent control of each channel, which significantly simplifies the system architecture.
[0051] In this embodiment, the use of a dual circularly polarized array eliminates the need for a 90-degree bridge, reducing the number of passive components, lowering insertion loss and system complexity, and improving receiver sensitivity and transmission efficiency.
[0052] Meanwhile, the cross-polarization isolation of the dual circular polarization array itself is generally better than that of the combination of "linear polarization unit + 90-degree bridge". Therefore, the amplitude of the cross-polarization component that needs to be compensated is smaller, and the dynamic range requirement for compensation is lower. Moreover, the phase orthogonality of the 90-degree bridge changes significantly with frequency, which limits the broadband performance of the dual linear polarization scheme. The dual circular polarization unit can achieve broadband circular polarization through its own structure (such as by using multi-layer feeding or sequential rotation array). With the dynamic compensation of this invention, a low axial ratio can be maintained over a wider frequency band.
[0053] The method and system provided by this invention can be widely applied to satellite communication phased array antennas, terrestrial mobile communication base station antennas, and other fields. They are particularly suitable for circularly polarized transceiver systems that require high polarization purity and need to meet stringent network access standards.
[0054] It should be noted that the specific manner in which each module performs its operation in the apparatus described in the above embodiments has been described in detail in the embodiments of the method, and will not be elaborated here.
[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A method for dynamic compensation of axial ratio of circular polarization of an antenna, characterized in that, include: Obtain the amplitude and phase characteristics of the cross-polarization components in the main polarization channel of the antenna at the target pointing angle; Based on the amplitude and phase characteristics, a compensation signal is generated on the cross-polarization channel of the antenna, and the compensation signal has the same amplitude and opposite phase to the cross-polarization component. The compensation signal is combined with the signal of the main polarization channel to obtain the compensated circularly polarized output signal; wherein the cross-polarization component in the circularly polarized output signal is suppressed.
2. The method of claim 1, wherein, The compensation signal is obtained by adjusting the compensation phase shifter and compensation attenuator set on the cross-polarization channel.
3. The method of claim 1, wherein the method further comprises: Obtaining the amplitude and phase characteristics of the cross-polarization components in the main polarization channel specifically includes: Directly measure the cross-polarization component of the main polarization channel at the target pointing angle; or Measure the axial ratio of the antenna at the target pointing angle, and iteratively adjust the compensation signal until the axial ratio meets the preset index.
4. The method of claim 1, wherein, Also includes: The correspondence between the beam pointing angle and the compensation signal is pre-calibrated, and the corresponding compensation signal is dynamically invoked according to the current pointing angle when the antenna is working.
5. The method of claim 1, wherein, The main polarization channel and the cross polarization channel share the same pointing phase shifter to ensure consistent beam pointing.
6. The method of claim 1, wherein, The antenna is a dual-linear polarized array antenna or a dual-circular polarized array antenna.
7. The method of claim 6, wherein the method further comprises: The signals from the main polarization channel and the cross-polarization channel are combined or separated by a coupler.
8. An antenna circular polarization axial ratio dynamic compensation system, applied to the method in any one of claims 1 to 7, characterized in that, The system includes: An array antenna is used to receive or transmit circularly polarized signals. A pointing phase shifter is used to control the beam pointing. The feed network is used to decompose the antenna signal into a main polarization channel and a cross-polarization channel; A compensation phase shifter and a compensation attenuator are disposed on the cross-polarization channel to generate the compensation signal.
9. The system of claim 8, wherein the system further comprises a plurality of phase shifters, each of the plurality of phase shifters being coupled to one of the plurality of antenna elements. The power supply network includes a 90-degree bridge or a circularly polarized power supply network.
10. The system of claim 9, wherein the system further comprises a plurality of phase shifters, each of the plurality of phase shifters being coupled to one of the plurality of antenna elements. All radiation channels of the array antenna share the same set of compensation values from the compensation phase shifter and compensation attenuator.