Low-profile broadband circularly polarized phased array antenna elements, antenna arrays and fabrication methods

Abstract

This invention relates to the field of phased array antenna technology, specifically disclosing a low-profile broadband circularly polarized phased array antenna element, antenna array, and fabrication method. The antenna includes a body and interconnected feed layers disposed at the bottom of the body. The body comprises, from top to bottom, a parasitic patch, a first dielectric layer, a radiating patch, and a second dielectric layer. A metallized via, coaxial with the body and interconnected with the radiating patch, is disposed on the second dielectric layer. The feed layer is interconnected with the metallized via. A U-shaped slot is disposed on the radiating patch. The metallized via is located within the U-shaped region formed by the U-shaped slot. Compared with the traditional eccentric feeding method, this invention reduces the antenna profile height, lowers fabrication costs, broadens the impedance bandwidth and axial ratio bandwidth, and optimizes the antenna's axial ratio performance.

Description

Technical Field

[0001] This invention relates to the field of phased array antenna technology, and more specifically, to low-profile broadband circularly polarized phased array antenna elements, antenna arrays, and fabrication methods. Background Technology

[0002] With the rapid development of modern wireless technology, the advantages of circularly polarized antennas have become increasingly prominent. Compared with linearly polarized antennas, circularly polarized antennas have more advantages, such as the ability to receive arbitrary polarized waves, resistance to multipath interference, and rotational orthogonality. Circularly polarized antennas are widely used in satellite communication, radar navigation, and many other fields.

[0003] A phased array antenna consists of multiple small antenna elements. By controlling the phase of each element, dynamic control of the beam direction and shape can be achieved. To improve the axial ratio of the array, circularly polarized antennas typically employ rotational arraying. Traditional circularly polarized microstrip antennas generally have narrow impedance bandwidths, and their axial ratio bandwidth is even narrower than their impedance bandwidth; and as... Figure 4 As shown, the feed port of a traditional single-fed circularly polarized antenna is usually located off-center to excite the circularly polarized signal. When the antenna elements are rotated and arrayed, the off-center feeding of the antenna elements makes it impossible for the feed ports of the array antennas to be in a straight line and not to correspond one-to-one with the active modules. It is necessary to add a stripline adapter to rotate the antenna feed ports to the required positions so that all the antenna feed ports are in a straight line after the circularly polarized antenna elements are rotated and arrayed.

[0004] Currently, traditional microstrip circularly polarized antennas have very narrow impedance bandwidth and axial ratio bandwidth, typically around 3% relative bandwidth. Therefore, it is particularly important to design a circularly polarized antenna with a low profile and wide impedance bandwidth and axial ratio bandwidth.

[0005] Chinese patent CN112134012B discloses a circularly polarized antenna and a circularly polarized array antenna. The circularly polarized antenna contains three layers of dielectric material. After the signal enters the transmission line, it is coupled through the gaps between the different layers. By adjusting the lengths of two different gaps, the circularly polarized wave transmission of the antenna is achieved. However, the antenna has a spacing of 0.81λ between the centers of each circularly polarized low-profile broadband circularly polarized phased array antenna element, which makes the antenna size too large and unsuitable for use in conventional phased array antenna systems.

[0006] Chinese patent CN112271439B discloses a circularly polarized microstrip antenna. This antenna comprises four dielectric layers and includes a 1-to-2 feed network. The circularly polarized feed network consists of an equal-power circularly ring-shaped microstrip feed line and two feed traces of unequal length connected sequentially to the same endpoint of the equal-power circularly ring-shaped microstrip feed line. A 90° phase difference between the two unequal-length feed traces enables the antenna to radiate circularly polarized waves. The antenna has an impedance bandwidth of approximately 1.7% (VSWR better than 2), which is narrow and unsuitable for use in broadband circularly polarized antennas. Furthermore, the antenna requires two lamination processes, resulting in a complex structure, high manufacturing difficulty, and high cost. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a low-profile broadband circularly polarized phased array antenna element, antenna array, and fabrication method, which reduces the antenna profile height, reduces fabrication costs, broadens impedance bandwidth and axial ratio bandwidth, and optimizes the axial ratio performance of the antenna compared with the traditional eccentric feeding method. The solution adopted by this invention to solve the technical problem is: on the one hand: A low-profile broadband circularly polarized phased array antenna element includes a body and a feed layer disposed at the bottom of the body and interconnected therewith. The main body consists of a parasitic patch, a dielectric layer one, a radiating patch, and a dielectric layer two, which are stacked from top to bottom. A metallized via is provided on the second dielectric layer, which is coaxial with the body and interconnected with the radiating patch; the feed layer is interconnected with the metallized via; The radiating patch has a U-shaped slit; the metallized through-hole is located within the U-shaped area formed by the U-shaped slit.

[0008] In some possible implementations, a power supply port is provided on the power supply layer that is coaxial with the body and interconnected with a metallized via.

[0009] In some possible implementations, the U-shaped gap includes two sets of parallel branches and a connecting joint for connecting the two sets directly; the metallized through-hole is located between the two sets of branches.

[0010] In some possible implementations, the distance between the metallized via and the two sets of branches is equal.

[0011] In some possible implementations, the two sets of branches are not of equal length.

[0012] In some possible implementations, an adhesive sheet is provided between the first dielectric layer and the radiating patch, and the parasitic patch, the first dielectric layer, the adhesive sheet, the radiating patch, the second dielectric layer, and the feed layer are manufactured by a single lamination process.

[0013] In some possible implementations, the parasitic patch is a chamfered patch.

[0014] on the other hand: An antenna array includes multiple sets of antenna subarrays arranged in an array; Each antenna subarray comprises four groups of low-profile broadband circularly polarized phased array antenna elements as described above; the four groups of low-profile broadband circularly polarized phased array antenna elements in each antenna subarray are arranged in a 2x2 matrix.

[0015] In some possible implementations, the four sets of low-profile broadband circularly polarized phased array antenna elements are rotated in a counterclockwise order of 0°, 90°, 180°, and 270° respectively; the four sets of low-profile broadband circularly polarized phased array antenna elements are fed with initial phases of 0°, -90°, -180°, and -270° respectively.

[0016] On the other hand: A fabrication method for a low-profile broadband circularly polarized phased array antenna element based on the above-described method specifically includes the following steps: The parasitic patch, dielectric layer one, radiating patch, dielectric layer two and feed layer stacked from top to bottom are pressed together to form an integral structure; A hole is drilled at the center of the overall structure to create a through hole; Metallize the through holes; Back-drill the corresponding via areas on the parasitic patch, dielectric layer 1, and radiation patch; The back-drilled portion is plugged; The side of the feed layer away from the second dielectric layer is etched to form a feed port coaxial with the via.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The low-profile broadband circularly polarized phased array antenna element in this invention has a low profile and a wide bandwidth, making it suitable for a wide range of applications. The low-profile circularly polarized antenna proposed in this invention is a microstrip low-profile broadband circularly polarized phased array antenna element, which is laminated in one step and manufactured using PCB processing technology. The manufacturing process is simple and the cost is low.

[0018] The circularly polarized low-profile broadband circularly polarized phased array antenna element proposed in this invention has its feed port located at the center of the low-profile broadband circularly polarized phased array antenna element. After the antenna array is rotated and assembled, the feed position is a straight line, which can be directly connected to the active module without the need for relay. Compared with the traditional eccentric feeding method, it reduces the antenna profile height and reduces the processing cost. The circularly polarized antenna proposed in this invention has a wide impedance bandwidth and a wide axial ratio bandwidth. The -10dB impedance bandwidth is greater than 52.6%, the axial ratio bandwidth is greater than 39.5%, and the axial ratio is less than 3dB within the ±50° range of the center frequency. The low-profile broadband circularly polarized phased array antenna element further optimizes the axial ratio performance of the antenna by rotating the array. Attached Figure Description

[0019] Figure 1 This is an exploded view of the low-profile broadband circularly polarized phased array antenna element in this invention. Figure 2 This is a schematic diagram of the stacked low-profile broadband circularly polarized phased array antenna element in this invention. Figure 3 This is a schematic diagram of the structure of the dielectric layer 2 and the radiative patch in this invention; Figure 4 This is a schematic diagram of a traditional circularly polarized antenna; Figure 5 This is a current distribution diagram of the radiating patch in this invention; Figure 6 This is a current distribution diagram of the parasitic patch in this invention; Figure 7 This is a schematic diagram of the simulation results of the low-profile broadband circularly polarized phased array antenna element in this invention. Figure 8 The axial ratio of the low-profile broadband circularly polarized phased array antenna element in this invention varies with frequency. Figure 9 The center frequency axial ratio of the low-profile broadband circularly polarized phased array antenna element in this invention; Figure 10 This is the center frequency pattern of the low-profile broadband circularly polarized phased array antenna element in this invention. Figure 11 This is a schematic diagram showing the rotation sequence of the antenna subarray in this invention; Figure 12 This is a schematic diagram of the antenna array in this invention; Figure 13 The scanning direction and axial ratio diagram of the antenna array at Phi=0° in this invention; Figure 14 The scanning direction and axial ratio of the antenna array at Phi=90° in this invention; in: 1. Parasitic patch; 2. Dielectric layer one; 3. Radiation patches; 31. U-shaped gap; 4. Dielectric layer two; 5. Feed layer; 51. Power supply port; 6. Adhesive sheet; 10. Metallized through holes. Detailed Implementation

[0020] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," etc., do not indicate a quantity limitation, but rather indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more. For example, multiple positioning posts refer to two or more positioning posts. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] The present invention will now be described in detail.

[0022] on the one hand: like Figure 1 , Figure 2 , Figure 3 As shown, a low-profile broadband circularly polarized phased array antenna element includes a body and a feed layer 5 disposed at the bottom of the body and interconnected therewith; a feed port 51 coaxial with the body and interconnected with a metallized through-hole 10 is provided on the feed layer 5. The main body consists of parasitic patch 1, dielectric layer 1, radiative patch 3, and dielectric layer 2 stacked from top to bottom; A metallized via 10 is provided on the dielectric layer 4, which is coaxial with the body and interconnected with the radiating patch 3, so that the metallized via 10 is located at the structural center of the body. The power feeding layer 5 is interconnected with the metallized via 10 through the power feeding port 51. The radiation patch 3 is provided with a U-shaped slit 31; the metallized through hole 10 is located in the U-shaped area formed by the U-shaped slit 31.

[0023] With the above configuration, the feed port 51 of the low-profile broadband circularly polarized phased array antenna element is always in a straight line when rotating and assembling, realizing direct feeding, which facilitates docking with active modules and eliminates the need for relays. Compared with the traditional eccentric feeding method, it reduces the antenna profile height and manufacturing costs.

[0024] The present invention effectively broadens the bandgap of the antenna array by using the parasitic patch 1 and the radiating patch 3 with the U-shaped slot 31; the radiating patch 3 with the U-shaped slot 31 serves as the driving patch for the low-profile broadband circularly polarized phased array antenna element, thereby achieving circularly polarized radiation. Using a U-shaped slot 31 as the antenna feed position, located at the center of the low-profile broadband circularly polarized phased array antenna element, the antenna feed position is on a straight line during rotation arraying, eliminating the need for an additional stripline relay, reducing design difficulty and manufacturing complexity. The antenna can be pressed together in one step, further reducing antenna manufacturing costs. Rotating the low-profile broadband circularly polarized phased array antenna element further optimizes the antenna's axial ratio. The array antenna achieves a ±50° pattern scan, and the antenna gain, sidelobes, directivity, and scan drop all perform well.

[0025] In some possible implementations, the U-shaped slit 31 includes two sets of parallel branches and a connecting joint for connecting the two sets directly; the metallized through hole 10 is located between the two sets of branches; the distance between the metallized through hole 10 and the two sets of branches is equal.

[0026] In order to effectively achieve circularly polarized radiation through the U-shaped gap, the lengths of the two sets of stubs are not equal, and thus the different lengths of the two sets of stubs excite the circular polarization performance of the antenna to achieve circularly polarized radiation.

[0027] An adhesive sheet 6 is provided between the first dielectric layer 2 and the radiating patch 3. The parasitic patch 1, the first dielectric layer 2, the adhesive sheet 6, the radiating patch 3, the second dielectric layer 4, and the feeding layer 5 are manufactured by a single pressing process. This arrangement simplifies and facilitates the processing, and reduces processing costs.

[0028] In some possible implementations, the parasitic patch 1 is a chamfered patch.

[0029] Based on the above settings, simulation analysis was performed on a low-profile broadband circularly polarized phased array antenna element, such as... Figure 5 and Figure 6 As shown, the current distribution changes of the radiating patch 3 and the parasitic patch 1 are shown. It can be seen that the current of the radiating patch 3 and the parasitic patch 1 changes periodically with time, thereby determining the polarization direction of the present invention. Specifically, at t=0, the current in the radiating patch 3 is mainly distributed vertically downward from the center of the radiating patch 3; At time t=T / 4, the current in radiating patch 3 is mainly distributed horizontally to the right from the center of radiating patch 3. At time t=3T / 4, the current in the radiating patch 3 is mainly distributed vertically upward along the outer edge of the radiating patch 3. At time t=T, the current in radiating patch 3 is mainly distributed horizontally to the left from the center of radiating patch 3. At time t=0, the current in parasitic patch 1 is mainly distributed horizontally to the left from the center of parasitic patch 1; At time t=T / 4, the current in parasitic patch 1 is mainly distributed vertically downward from the center of parasitic patch 1; At time t=3T / 4, the current in parasitic patch 1 is mainly distributed horizontally to the right from the center of parasitic patch 1; At time t=T, the current in parasitic patch 1 is mainly distributed vertically upward at the center of parasitic patch 1.

[0030] The U-shaped slot 31 of the radiating patch 3 and the chamfer setting of the parasitic patch 1 cause the current to rotate counterclockwise. Here, counterclockwise means looking along the direction perpendicular to the screen, thereby enabling the antenna to achieve right-hand circularly polarized wave radiation.

[0031] The low-profile broadband circularly polarized phased array antenna element adopts a microstrip form and operates in the frequency band of 14GHz~24GHz; the simulation results of the low-profile broadband circularly polarized phased array antenna element are as follows: Figures 8-10 As shown, the simulation results indicate that the -10dB impedance bandwidth is greater than 52.6% (14GHz~24GHz), the axial ratio bandwidth is better than 3dB and greater than 39.5% (14.96GHz~22.34GHz), and the axial ratio is less than 3dB within the ±50° range of the center frequency.

[0032] on the other hand: like Figure 11 , Figure 12 As shown, an antenna array includes multiple antenna subarrays arranged in an array. Each antenna subarray comprises four groups of low-profile broadband circularly polarized phased array antenna elements as described above; the four groups of low-profile broadband circularly polarized phased array antenna elements in each antenna subarray are arranged in a 2x2 matrix. like Figure 11 As shown, the four sets of low-profile broadband circularly polarized phased array antenna elements in the low-profile broadband phased array antenna unit are rotated in a counterclockwise order of 0°, 90°, 180°, and 270° respectively. That is, the physical placement angles of the four sets of low-profile broadband circularly polarized phased array antenna elements in a counterclockwise order are 0°, 90°, 180°, and 270° respectively. The four sets of low-profile broadband circularly polarized phased array antenna elements are fed with excitation signals with initial phases of 0°, -90°, -180°, and -270° in sequence. This setting will further improve the axial ratio of the array.

[0033] Antenna arrays such as Figure 12 The 8x8 array shown, after electromagnetic software simulation, has the following scanning pattern and axial ratio distribution at the center frequency point: Figure 13 , Figure 14 As shown, the antenna gain drops by more than 3dB in the ±50° scanning range at the Phi=0° and Phi=90° profiles, and the axial ratio is more than 3dB in the scanning range.

[0034] On the other hand: A fabrication method for a low-profile broadband circularly polarized phased array antenna element based on the above-described method specifically includes the following steps: The parasitic patch 1, dielectric layer 1, radiating patch 3, dielectric layer 2, and feed layer 5, which are stacked from top to bottom, are pressed together in one step to form an integral structure. A hole is drilled at the center of the overall structure to create a through hole; The vias are metallized to enable the radiating patch 3 to interconnect with the feed layer 5. Back-drill the corresponding via areas on parasitic patch 1, dielectric layer 1 2, and radiating patch 3 to form metallized vias 10 on dielectric layer 2 4. The back-drilled portion is plugged with resin and then plated flat. The side of the feed layer 5 away from the dielectric layer 4 is etched to form a feed port 51 coaxial with the via, so that the feed port 51 is interconnected with the metallized via 10 formed after metallization.

[0035] Using the above method to fabricate low-profile broadband circularly polarized phased array antenna elements will greatly reduce the fabrication difficulty and cost.

[0036] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A low-profile broadband circularly polarized phased array antenna element, characterized in that, Includes the main body and the interconnected power supply layer located at the bottom of the main body; The main body consists of a parasitic patch, a dielectric layer one, a radiating patch, and a dielectric layer two, which are stacked from top to bottom. A metallized via is provided on the second dielectric layer, which is coaxial with the body and interconnected with the radiating patch; the feed layer is interconnected with the metallized via; The radiating patch has a U-shaped slit; the metallized through-hole is located within the U-shaped area formed by the U-shaped slit.

2. The low-profile broadband circularly polarized phased array antenna element according to claim 1, characterized in that, A power supply port, coaxial with the body and interconnected with a metallized via, is provided on the power supply layer.

3. The low-profile broadband circularly polarized phased array antenna element according to claim 2, characterized in that, The U-shaped gap includes two sets of parallel branches and a connecting joint for connecting the two sets directly; the metallized through hole is located between the two sets of branches.

4. A low-profile broadband circularly polarized phased array antenna element according to claim 3, characterized in that, The distance between the metallized through-hole and the two sets of branches is equal.

5. A low-profile broadband circularly polarized phased array antenna element according to claim 3, characterized in that, The lengths of the branches in the two groups are not equal.

6. A low-profile broadband circularly polarized phased array antenna element according to any one of claims 1-5, characterized in that, An adhesive sheet is provided between the first dielectric layer and the radiating patch. The parasitic patch, the first dielectric layer, the adhesive sheet, the radiating patch, the second dielectric layer, and the feeding layer are manufactured by a single pressing process.

7. A low-profile broadband circularly polarized phased array antenna element according to claim 1, characterized in that, The parasitic patch is a chamfered patch.

8. An antenna array, characterized in that, Includes multiple antenna subarrays arranged in an array; Each antenna subarray comprises four groups of low-profile broadband circularly polarized phased array antenna elements as described in any one of claims 1-7; the four groups of low-profile broadband circularly polarized phased array antenna elements in each antenna subarray are arranged in a 2x2 matrix.

9. An antenna array according to claim 8, characterized in that, The four groups of low-profile broadband circularly polarized phased array antenna elements are rotated in a counterclockwise order of 0°, 90°, 180°, and 270° respectively; the four groups of low-profile broadband circularly polarized phased array antenna elements are fed with initial phases of 0°, -90°, -180°, and -270° respectively.

10. A method for fabricating a low-profile broadband circularly polarized phased array antenna element according to any one of claims 1-7, characterized in that, Specifically, the following steps are included: The parasitic patch, dielectric layer one, radiating patch, dielectric layer two and feed layer stacked from top to bottom are pressed together to form an integral structure; A hole is drilled at the center of the overall structure to create a through hole; Metallize the through holes; Back-drill the corresponding via areas on the parasitic patch, dielectric layer 1, and radiation patch; The back-drilled portion is plugged; The side of the feed layer away from the second dielectric layer is etched to form a feed port coaxial with the via.

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