A broadband dual circularly polarized U-slot patch antenna

Abstract

The present invention belongs to the field of antenna technology, specifically a broadband dual circularly polarized U-slot patch antenna. The antenna of the present invention includes three parts: an upper copper foil metal patch, an intermediate dielectric layer and a lower metal floor. The metal patch is square as a whole, with a symmetrical U-shaped slot in the middle; two coaxial feeding probes are inserted into the two corresponding cylindrical holes in the dielectric plate and the floor, and are directly connected to the upper metal patch to excite the antenna. A new mode is introduced by the U-shaped slot, and the characteristics of the TM10 and TM01 modes of the original patch antenna can be effectively adjusted. When the antenna is working, three orthogonal modes will be excited at the same time, effectively expanding the circular polarization bandwidth of the patch antenna; due to the symmetry of the structure, the wave rotation directions excited by the two probes correspond to left-hand circular polarization and right-hand circular polarization respectively, and the radiated waves are the same except for the different rotation directions.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and in particular relates to a broadband dual circularly polarized patch antenna. Background Art

[0002] Linearly polarized waves are easily affected by factors such as climate, environment, and carrier motion, leading to polarization shift and even failure. Circularly polarized waves, on the other hand, experience less polarization loss and can even experience polarization reversal when encountering reflective objects. Therefore, in wireless communications, especially satellite communications, these properties of circularly polarized waves are often utilized to mitigate the effects of rain, fog, the ionosphere, and other factors on electromagnetic wave propagation. Consequently, circularly polarized antennas are widely used in these fields. Common circularly polarized antennas include patch antennas, helical antennas, and dipole antennas. Compared to helical and dipole antennas, patch antennas offer advantages such as low profile, ease of manufacture, high machining precision, and conformal conformality with the carrier, leading to their widespread use. However, the major drawback of patch antennas is their narrow operating frequency band, which limits their application. Furthermore, to ensure strong anti-interference and anti-fading capabilities, circularly polarized antennas often require integrated transmit and receive capabilities, necessitating dual circularly polarized antennas. While there are numerous methods for achieving circular polarization, the number of methods for implementing dual circularly polarized antennas is quite limited.

[0003] To achieve broadband, dual circularly polarized antenna characteristics, existing patch antennas often use thick dielectric substrates to extend the bandwidth and are fed using a 3dB branch-line coupling network. The network's two input ports serve as right-hand circularly polarized and left-hand circularly polarized inputs, with energy then coupled in through the slots. However, the thick dielectric substrate results in a high antenna profile and excessive weight, increasing manufacturing costs. Furthermore, the 3dB branch-line coupling network complicates the feed network and hinders processing. Therefore, research on broadband dual circularly polarized patch antennas with a simple feeding structure is of great significance and practical value. Summary of the Invention

[0004] The present invention aims to provide a broadband dual-circularly polarized U-slot patch antenna. This antenna effectively expands its bandwidth by utilizing its three orthogonal modes without increasing the antenna's size or using a complex feed structure. Furthermore, by leveraging the symmetry of the antenna structure, symmetrical placement of the feed ports allows the antenna to radiate circularly polarized waves in a different handedness.

[0005] The broadband dual circularly polarized U-slot patch antenna provided by the present invention consists of the following three components:

[0006] The first part is the upper metal patch, which is the main radiating part of the antenna. It uses a printed copper foil metal layer. The metal patch is square in shape and 18-35 microns thick. It has a symmetrical U-shaped groove. The line width of the U-shaped groove should be 0.8-1.5 mm wide and 18-35 microns deep. The length and spacing of the two arms are both smaller than the side length of the square patch. The specific dimensions are determined by the impedance and axial ratio bandwidth required by the actual antenna. This symmetrical U-shaped groove can not only introduce a new mode, but also effectively adjust the characteristics of the TM10 and TM01 modes of the patch antenna. The three modes are excited simultaneously to radiate broadband circularly polarized electromagnetic waves.

[0007] The second part is the intermediate dielectric layer, which is the carrier of the metal patch and is used to support the metal patch. The dielectric layer is a rectangular parallelepiped with a square bottom and a certain thickness. A cylindrical hole with a small aperture (such as 0.6-1 mm) is opened at two symmetrical feeding positions. The dielectric layer uses a dielectric material with a high dielectric constant, which is conducive to the miniaturization of the antenna.

[0008] The third section is the lower metal floor. This floor is square in shape and features two larger cylindrical holes (e.g., 3-5 mm) located at the corresponding locations in the dielectric layer. These holes are used to insert two feed probes. The floor reflects electromagnetic waves, increasing antenna gain.

[0009] Two coaxial feeding probes are inserted into two corresponding cylindrical holes in the dielectric plate and the floor respectively, and are directly connected to the upper metal patch to excite the antenna.

[0010] When the antenna is operating, three orthogonal modes are excited simultaneously, effectively expanding the patch antenna's circularly polarized bandwidth. Due to the symmetry of the structure, the two probes excite waves with left-handed and right-handed circular polarization, respectively. The radiated waves are identical except for their different handedness.

[0011] The antenna structure of the present invention is simple, and dual circular polarization can be easily realized, while the circular polarization bandwidth is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of the structure of the broadband dual circularly polarized U-slot patch antenna.

[0013] Figure 2 This is the resonant mode distribution diagram of the broadband dual circularly polarized U-slot patch antenna.

[0014] Figure 3 This is the simulation diagram of the return loss and port isolation of the broadband dual circularly polarized U-slot patch antenna.

[0015] Figure 4 This is the axial ratio simulation diagram of the broadband dual circularly polarized U-slot patch antenna.

[0016] Figure 5 is the xoy plane radiation pattern of the broadband dual circularly polarized U-slot patch antenna at 14 GHz.

[0017] Figure 6 is the yoz plane pattern of the broadband dual circularly polarized U-slot patch antenna at 14 GHz.

[0018] The numbers in the figure are: 1 is the upper metal patch, 2 is the symmetrical U-shaped gap on the patch, 3 is the middle dielectric plate, 4 is the lower metal floor, 5 is the cylindrical hole on the dielectric plate, and 6 is the cylindrical hole on the floor. DETAILED DESCRIPTION

[0019] The antenna utilizes a "metal-dielectric-metal" sandwich structure. First, a 18-35 micron thick upper copper foil patch 1 is printed on a dielectric substrate 3 (select the appropriate substrate based on actual needs) using a PCB process. A symmetrical U-shaped slot 2 is then created in this patch 1. The slot width should be 0.8-1.5 mm and the depth should be 18-35 microns. The length and spacing of the two arms should be less than the side length of the square patch. The specific dimensions are determined by the impedance and axial bandwidth required for the antenna. Two thin cylindrical holes 5 with a diameter of 0.8 mm are drilled at the feed position of the dielectric substrate 3. A metal floor 4 is then attached below the dielectric substrate 3. Similarly, a thick cylindrical hole 6 with a diameter of 4.0 mm is drilled above the metal floor 4 at the same feed position. The assembly is complete. For use, simply insert a coaxial probe.

[0020] like Figure 1 The figure shows the structure of the broadband dual circularly polarized U-slot patch antenna. The antenna can be assembled by following the instructions above.

[0021] like Figure 2 Shown is the resonant mode distribution diagram of the broadband dual circularly polarized U-slot patch antenna.

[0022] like Figure 3 Shown is the return loss and port isolation simulation diagram of the broadband dual circularly polarized U-slot patch antenna.

[0023] like Figure 4 Shown is the axial ratio simulation diagram of the broadband dual circularly polarized U-slot patch antenna.

[0024] like Figure 5 Shown is the xoy plane radiation pattern of the broadband dual circularly polarized U-slot patch antenna at 14 GHz.

[0025] like Figure 6 Shown is the yoz plane pattern of the broadband dual circularly polarized U-slot patch antenna at 14 GHz.

Claims

1. A broadband dual circularly polarized U-slot patch antenna, characterized in that: Adopting a "metal-dielectric-metal" sandwich structure, copper foil metal patches are printed on the dielectric board using PCB technology, and a metal floor is attached under the dielectric board: The copper foil metal patch is the main radiating part of the antenna. The metal patch is square in shape, with a thickness of 18-35 microns. It has a symmetrical U-shaped slot. This symmetrical U-shaped slot introduces a new mode and can effectively adjust the characteristics of the patch antenna's TM10 and TM01 modes. These three modes are excited simultaneously, radiating broadband circularly polarized electromagnetic waves. The dielectric plate is a carrier for the copper foil metal patch and is used to support the copper foil metal patch. The dielectric plate is a rectangular parallelepiped with a square bottom and a thickness of 3-5 mm. It has a cylindrical hole with a diameter of 0.6-1 mm at two symmetrical feeding positions. The dielectric plate is made of a dielectric material with a high dielectric constant. The feeding position is located inside the U-shaped slot and close to the ends of the two arms of the U-shaped slot. The metal floor is square in shape. There are cylindrical holes with a diameter of 3-5 mm at the corresponding positions of the two cylindrical holes in the dielectric plate for inserting two feeding probes. Two coaxial feeding probes are inserted into two corresponding cylindrical holes in the dielectric plate and the metal floor respectively, and are directly connected to the copper foil metal patch to excite the antenna; The U-shaped groove has a line width of 0.8-1.5 mm and a depth of 18-35 μm. The length and spacing of the two arms are both smaller than the side length of the square patch. The specific dimensions are determined according to the impedance and axial ratio bandwidth required by the actual antenna.

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