An antenna array implementing beamforming and circular polarization handedness switching

Abstract

This application discloses an antenna array for beamforming and circular polarization rotation switching, comprising: an antenna array; the antenna array including multiple antenna elements; a first power divider network having a first input excitation port and a first output port; a second power divider network having a second input excitation port and a second output port; an amplitude-phase multifunction chip connected to the first and second input excitation ports for controlling the phase difference between the first and second input excitation ports to be +90° or -90°; the first output port of the first power divider network connected to the first feed port of the antenna array; and the second output port of the second power divider network connected to the second feed port of the antenna array. Matching stubs are provided on the first and second power divider networks for adjusting the length and width of the matching stubs to control the feed amplitude and phase of each antenna element in the antenna array, thereby achieving beamforming of the antenna pattern. This application reduces the number of TR channels and lowers costs.

Description

Technical Field

[0001] This application relates to the field of antenna array technology, and in particular to an antenna array that realizes beamforming and circular polarization rotation switching. Background Technology

[0002] As the front end of a wireless communication system, the antenna plays a crucial role in transmitting and receiving electromagnetic wave signals. With the increasing volume of information being transmitted, current wireless communication systems require massive information throughput, thus placing higher demands on antenna performance. Antenna arrays offer unparalleled advantages over single antennas, such as high gain, strong directivity, and tunable beamforming. In certain communication scenarios, antennas also need to perform special functions. For example, many communication antennas need to radiate high-gain circularly polarized electromagnetic waves, and base station antennas typically need to implement multi-beam radiation modes. These requirements usually necessitate the use of antenna arrays. The desired radiation pattern of an antenna array includes not only the design of the antenna array element structure but also the design theory and methods required for the synthesized radiation waveform. In recent years, various antenna array structures and functions, as well as the beamforming theory of antenna arrays, have received extensive research.

[0003] Phased arrays, due to their ability to flexibly control phase and achieve antenna beam control, have seen a large number of control methods incorporated into antenna arrays. However, the resulting increase in cost is not negligible. Therefore, achieving a low-cost scheme with switchable beamforming and circular polarization has long been a research hotspot for scholars.

[0004] Currently, the main technical solutions for antenna arrays to achieve beamforming and circular polarization switching are as follows:

[0005] (1) Independent control architecture for each antenna element: Each antenna element is configured with an independent active channel, and beamforming and circular polarization switching are achieved simultaneously by independently controlling the feed amplitude and phase of each element. For example Figure 1 The scheme shown is as follows: 1 is an antenna unit and 12 is an amplitude-phase multifunction chip; each antenna unit is connected to an amplitude-phase multifunction chip, and beamforming and polarization switching are achieved by directly controlling the amplitude and phase of each unit.

[0006] Chinese patent CN210744178U, "A Phased Array Antenna Capable of Switching Between Left and Right Rotation Circular Polarization," mentions N... The TR subarray consists of four antenna elements and four TR channels. Each antenna element is a single-feed structure and corresponds to an independent TR channel. Each TR channel includes active components such as a phase shifter, attenuator, and amplifier, implemented by a four-in-one SOC chip and a TR transceiver chip. By independently controlling the feed amplitude and phase of each antenna element, this scheme can achieve beamforming and circular polarization switching.

[0007] (2) Amplitude-phase chip + bridge + switch architecture: such as Figure 2 As shown, 1 is the antenna element, 12 is the amplitude-phase multifunction chip, 13 is the bridge chip, and 14 is the switch chip. This scheme uses the amplitude-phase multifunction chip to control the amplitude and phase of each antenna element to achieve beamforming, and works in conjunction with the bridge to generate... The polarization mode is switched using a switching chip to compensate for the difference.

[0008] Whether it is the "independent control of each antenna element" architecture ( Figure 1 The scheme (and comparison document 1) still uses the "amplitude and phase chip + bridge + switch" architecture. Figure 2 In these schemes, the number of active channels is directly proportional to the number of antenna elements. Taking a 16-element array as an example, the above schemes require 16 to 32 active channels, each containing active devices such as phase shifters, attenuators, and amplifiers, resulting in a large number of chips, high cost, and high power consumption. Although phased array control offers superior performance, the resulting cost increase is not negligible.

[0009] Each active channel requires an independent control signal for amplitude and phase adjustment, resulting in a large number of control lines and complex wave control circuitry. Furthermore, the use of numerous active components increases the system's failure rate and debugging difficulty. Summary of the Invention

[0010] Based on this, and in response to the aforementioned technical problems, an antenna array that enables beamforming and circular polarization rotation switching is provided to address the issues of high cost, increased failure rate, and increased debugging difficulty in existing technologies.

[0011] In a first aspect, an antenna array for realizing beamforming and circular polarization rotation switching includes: an antenna array; an amplitude-phase multi-function chip; a first power divider network; and a second power divider network.

[0012] The antenna array includes multiple antenna elements arranged in an array.

[0013] The first power divider network has a first input excitation port and a first output port; the second power divider network has a second input excitation port and a second output port.

[0014] The amplitude-phase multifunction chip is connected to the first input excitation port and the second input excitation port, and is used to control the phase difference between the first input excitation port and the second input excitation port to be +90° or -90°, so as to realize the switching between left-hand circular polarization and right-hand circular polarization.

[0015] The first output port of the first power divider network is connected to the first feed port of the antenna array, and the second output port of the second power divider network is connected to the second feed port of the antenna array. Matching stubs are provided on the first power divider network and the second power divider network to control the feed amplitude and phase of each antenna element of the antenna array by adjusting the length and width of the matching stubs, thereby realizing beamforming of the antenna pattern.

[0016] Optionally, in the above scheme, the antenna array further includes: multiple shielding holes, which are equally spaced around each antenna element to form a closed shielding wall.

[0017] Optionally, in the above scheme, the antenna array further includes a metal ground, which is electrically connected to the grounding terminals of the antenna element, the first power divider network, the second power divider network, the first input excitation port, and the second input excitation port through multiple shielded ground holes to form a common reference ground.

[0018] Optionally, in the above scheme, the antenna element is a microstrip antenna element.

[0019] Optionally, in the above scheme, the type of the matching branch is a strip line.

[0020] In the above scheme, optionally, the length of the matching stub is configured to adjust the phase compensation amount of the corresponding branch, and the increase of the length of the matching stub increases the phase compensation amount;

[0021] The width and length of the matching stub are configured together to adjust the amplitude compensation amount of the corresponding branch, wherein increasing the width of the matching stub reduces the amplitude loss, and increasing the length of the matching stub increases the amplitude loss.

[0022] This application has at least the following beneficial effects:

[0023] This application employs an architecture with two input excitation ports and two sets of power divider networks, requiring only one amplitude-phase multifunction chip to control the phase difference between the two ports. This invention enables flexible switching between left-hand and right-hand circular polarization. Simultaneously, by adjusting the length and width of the matching stubs on the power divider network, static control of the feed amplitude and phase of each antenna element can be achieved, thereby realizing beamforming of the antenna pattern. This invention significantly reduces the number of active channels to two, independent of the number of antenna elements, thus significantly reducing the number of active devices such as amplitude and phase multifunction chips, lowering material costs and system power consumption, simplifying control circuit design, and improving system integration and reliability.

[0024] Furthermore, by setting shielded ground holes around the antenna elements, the present invention effectively improves the isolation between elements, reduces coupling interference, and further enhances array performance. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of an existing antenna array;

[0026] Figure 2 This is a cross-sectional view of an antenna array from another existing technology;

[0027] Figure 3 A structural diagram of an antenna array for implementing beamforming and circular polarization rotation switching, provided as an embodiment of this application;

[0028] Figure 4 A circuit schematic diagram of an antenna array for implementing beamforming and circular polarization rotation switching is provided in one embodiment of this application;

[0029] Among them, 1-antenna unit, 2-power divider network, 3-input excitation port, 4-ground hole, 5-input excitation port, 6-power divider network, 7-metal ground, 12-amplitude and phase multifunction chip, 13-bridge chip, and 14-switch chip. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0031] In the description of this application: unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," etc., in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (e.g., they should not be construed as an emphasis on importance or order). Expressions such as "including," "comprising," and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0032] In one embodiment, such as Figure 3As shown, an antenna array for realizing beamforming and circular polarization rotation switching is provided, including: an antenna array; an amplitude-phase multifunction chip; a first power divider network 2; and a second power divider network 6;

[0033] The antenna array includes multiple antenna elements 1 arranged in an array;

[0034] The first power divider network 2 has a first input excitation port 3 and a first output port; the second power divider network 6 has a second input excitation port 5 and a second output port.

[0035] The amplitude-phase multifunction chip is connected to the first input excitation port 3 and the second input excitation port 5 to control the phase difference between the first input excitation port 4 and the second input excitation port 5 to be +90° or -90°, so as to realize the switching between left-hand circular polarization and right-hand circular polarization.

[0036] The first output port of the first power divider network 2 is connected to the first feed port of the antenna array, and the second output port of the second power divider network 6 is connected to the second feed port of the antenna array. Matching stubs are provided on the first power divider network 2 and the second power divider network 6, which are used to control the feed amplitude and phase of each antenna element 1 of the antenna array by adjusting the length and width of the matching stubs, thereby realizing beamforming of the antenna pattern.

[0037] Specifically, the antenna array includes antenna element 1, power divider network 2, input excitation port 3, ground hole 4, input excitation port 5, power divider network 6, and metallic ground 7. A stable amplitude-phase multifunction chip is selected to control the phase of the two ports, making the phase difference between the two ports lead or lag by 90°, thereby achieving circular polarization switching. The signal is then fed into each antenna element 1 through power divider networks 2 and 6. Based on the beamforming pattern, the required amplitude and phase of each antenna element are calculated. Since the length and width of the matching stubs on the power divider network can be adjusted for amplitude and phase, the stubs of the power divider network can be adjusted to make the amplitude and phase of each antenna element 1 controllable, achieving antenna beamforming. To increase the isolation and reduce the coupling between antenna elements 1, shielding ground holes 4 are added around the antenna elements 1, improving both isolation and coupling. Finally, a stable chip is selected to control the phase of the two ports, making the phase difference between the two ports lead or lag by 90°, thereby achieving circular polarization switching.

[0038] In this embodiment, the amplitude-phase multifunction chip uses a commercially available integrated amplitude-phase control chip. This chip integrates a phase shifter, attenuator, and amplifier, and receives control commands via an SPI or I2C serial interface, allowing independent adjustment of the phase and amplitude of the two output ports. The amplitude-phase multifunction chip controls the phase difference between the first input excitation port 3 and the second input excitation port 5 to be +90° or -90°. Specifically, when the phase of the first input excitation port 3 lags behind the second input excitation port 5 by 90° (i.e., the phase difference is -90°), the antenna array radiates a right-hand circularly polarized wave; when the phase of the first input excitation port 3 leads the second input excitation port 5 by 90° (i.e., the phase difference is +90°), the antenna array radiates a left-hand circularly polarized wave. The principle is based on electromagnetic field theory: when the amplitudes of two orthogonally polarized electric field components are equal and their phases differ by ±90°, the resulting wave is a circularly polarized wave, and the sign of the phase difference determines the direction of rotation.

[0039] In the aforementioned antenna array that achieves beamforming and circular polarization rotation switching, by employing an architecture with two input excitation ports and two sets of power divider networks, only one amplitude-phase multifunction chip is needed to control the phase difference (+90° or -90°) between the two ports to achieve flexible switching between left-hand and right-hand circular polarization. Simultaneously, by adjusting the length and width of the matching stubs on the power divider network, static control of the feed amplitude and phase of each antenna element can be achieved, thereby realizing beamforming of the antenna pattern. This invention significantly reduces the number of active channels to two, independent of the number of antenna elements, thus significantly reducing the number of active devices such as the amplitude-phase multifunction chip, lowering material costs and system power consumption, simplifying control circuit design, and improving system integration and reliability.

[0040] In one embodiment, the antenna array further includes a plurality of shielding holes 4, which are equally spaced around each antenna element 1 to form a closed shielding wall.

[0041] In this embodiment, shielding holes 4 are evenly spaced around each antenna element 1, forming a closed shielding wall. In this embodiment, the shielding holes 4 effectively suppress the propagation of surface waves. Simulation tests show that after setting the shielding holes 4, the coupling S21 between adjacent antenna elements 1 is better than -20dB in the operating frequency band, which is an improvement of about 5dB compared to the case without ground holes.

[0042] In one embodiment, the antenna array further includes a metal ground 7, which is electrically connected to the grounding terminals of the antenna element 1, the first power divider network 2, the second power divider network 6, the first input excitation port 3, and the second input excitation port 5 through multiple shielded ground holes 4 to form a common reference ground.

[0043] In one embodiment, antenna element 1 is a microstrip antenna element.

[0044] In one embodiment, the type of matching branch is a strip.

[0045] In one embodiment, the length of the matching stub is configured to adjust the phase compensation amount of the corresponding stub, and increasing the length of the matching stub increases the phase compensation amount.

[0046] The width and length of the matching stub are configured together to adjust the amplitude compensation of the corresponding stub, wherein increasing the width of the matching stub reduces the amplitude loss, and increasing the length of the matching stub increases the amplitude loss.

[0047] In this embodiment, the length of the matching branch is configured to primarily adjust the phase compensation of the corresponding branch in proportion to the length, while the width has minimal impact. Therefore, adjusting the length is the decisive way to control the phase.

[0048] The width and length of the matching stub are configured to adjust the amplitude of the corresponding stub. The width is inversely proportional to the amplitude and directly proportional to the length. The wider the width, the smaller the equivalent resistance, that is, the wider the width, the lower the loss; while the length is the cumulative loss, the longer the length, the higher the loss.

[0049] First, based on the target beamforming pattern, calculate the target amplitude and target phase required for each antenna element 1. For example, if the target pattern is a low sidelobe beam, calculate the amplitude value of each element; if the target pattern is a beam with a specific direction, the phase of each element must satisfy a linear phase difference distribution.

[0050] Secondly, based on the target amplitude required by each unit, the power allocation ratio of the first power divider network 2 and the second power divider network 6, as well as the matching stub width on the corresponding branch of each antenna element 1, are determined. In this embodiment, the first power divider network 2 and the second power divider network 6 adopt an unequal power divider structure, and different power allocation ratios are achieved by adjusting the microstrip line width ratio of each output branch. The matching stub width on each branch is fine-tuned according to the remaining amplitude compensation amount, so that the signal amplitude finally fed to each antenna element 1 is consistent with the target amplitude.

[0051] Next, based on the target phase required by each unit, the length of the matching stub on the corresponding branch of each antenna unit 1 is determined. Since the transmission line length of the power divider network itself introduces a fundamental phase delay, the matching stub length is used to compensate for the phase difference between branches, ensuring that the feed phase of each unit meets the target phase distribution. Specifically, the length of the matching stub mainly affects phase adjustment, with the phase compensation amount being proportional to the length; the width and length of the matching stub together affect amplitude adjustment, where the width is inversely proportional to amplitude loss (the wider the width, the lower the loss), and the length is directly proportional to amplitude loss (the longer the length, the higher the loss).

[0052] Finally, the length and width of the matching branches are optimized using electromagnetic simulation software (such as ANSYS HFSS or CST Microwave Studio). For example, with the optimization objective of the sidelobe level being below -20dB, the length and width of each matching branch are used as optimization variables, and iterative optimization is performed using a genetic algorithm or gradient descent algorithm until the design requirements are met.

[0053] Those skilled in the art should understand that the above design method is merely an example, and other equivalent design methods may also be used, all of which fall within the protection scope of this invention.

[0054] The antenna array in this embodiment is particularly suitable for applications with fixed beam shapes but requiring polarization switching, such as base station antennas (sector coverage), satellite communication terminal antennas (point-to-point pointing), and point-to-point communication antennas. Taking a base station antenna as an example, the antenna array in this embodiment can be installed on the top of a base station tower, with beamforming into a cosecant square beam to achieve uniform coverage of ground cells; at the same time, by quickly switching between left and right circular polarization through an amplitude-phase multifunction chip, it can effectively combat rain attenuation and multipath fading, or achieve polarization diversity reception, improving the reliability of the communication link.

[0055] The beneficial effects of this application include:

[0056] 1. By using a power divider network to achieve controllable amplitude and phase from the port to each antenna element, beamforming can be realized. This method reduces the number of TR channels, lowers costs, and achieves high integration.

[0057] 2. Polarization switching is achieved by controlling the phase of the channel through the TR chip, thus facilitating control.

[0058] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An antenna array for achieving beamforming and circular polarization rotation switching, characterized in that, include: Antenna array; Amplitude-phase multifunctional chip, first power dividing network (2), second power dividing network (6); The antenna array includes multiple antenna elements (1) arranged in an array. The first power divider network (2) has a first input excitation port (3) and a first output port; the second power divider network (6) has a second input excitation port (5) and a second output port; The amplitude-phase multifunction chip is connected to the first input excitation port (3) and the second input excitation port (5) to control the phase difference between the first input excitation port (3) and the second input excitation port (5) to be +90° or -90°, so as to realize the switching between left-hand circular polarization and right-hand circular polarization; The first output port of the first power divider network (2) is connected to the first feed port of the antenna array, and the second output port of the second power divider network (6) is connected to the second feed port of the antenna array. Matching stubs are provided on the first power divider network (2) and the second power divider network (6) to control the feed amplitude and phase of each antenna element (1) of the antenna array by adjusting the length and width of the matching stubs, thereby realizing beamforming of the antenna pattern.

2. The antenna array for beamforming and circular polarization rotation switching according to claim 1, characterized in that, The antenna array further includes multiple shielding holes (4), which are equally spaced around each antenna element (1) to form a closed shielding wall.

3. The antenna array for achieving beamforming and circular polarization rotation switching according to claim 2, characterized in that, The antenna array further includes a metal ground (7), which is electrically connected to the grounding terminals of the antenna unit (1), the first power divider network (2), the second power divider network (6), the first input excitation port (3), and the second input excitation port (5) through multiple shielded ground holes (4) to form a common reference ground.

4. The antenna array for achieving beamforming and circular polarization rotation switching according to claim 1, characterized in that, The type of the antenna element (1) is a microstrip antenna element.

5. The antenna array for achieving beamforming and circular polarization rotation switching according to claim 1, characterized in that, The type of the matching branch is a banded line.

6. The antenna array for achieving beamforming and circular polarization rotation switching according to claim 1, characterized in that, The length of the matching stub is configured to adjust the phase compensation amount of the corresponding branch, and increasing the length of the matching stub increases the phase compensation amount. The width and length of the matching stub are configured together to adjust the amplitude compensation amount of the corresponding branch, wherein increasing the width of the matching stub reduces the amplitude loss, and increasing the length of the matching stub increases the amplitude loss.

Images