Dual-band common-caliber circularly polarized reflector antenna

Abstract

The invention discloses a dual-band common-caliber circularly polarized reflector antenna, which comprises a metal reflector, a high-band helical antenna, a low-band annular dipole array, a dielectric cylinder, a coaxial cable and a constant-amplitude in-phase power divider, the high-frequency-band helical antenna is fixed on the metal reflecting surface in a suspended manner through three dielectric cylinders, and the radiation direction points to the reflecting surface antenna; the low-frequency-band annular dipole array is annularly distributed by taking the center of the metal reflecting surface as a circle center, the physical rotation angles are sequentially 0 degree, 90 degrees, 180 degrees and 270 degrees, and circular polarization is realized through feeding of an equal-amplitude in-phase power divider; and the coaxial cable is used as a feed connecting line of the high-band helical antenna. Through a reflecting surface structure multiplexing technology, the functions of high-frequency reflection and low-frequency grounding are realized, and common-caliber integration is successfully realized under the condition that an FSS is not needed; port isolation between high and low frequencies is achieved through reasonable space distribution, and it is guaranteed that circular polarization directional diagrams achieve good directivity and axial ratio.

Description

Technical Field

[0001] The present invention relates to the field of antennas, and in particular to a dual-band common-aperture circularly polarized reflector antenna. Background Art

[0002] In modern communication and radar technologies, it is often necessary for antennas to operate simultaneously in two different frequency bands to meet different communication requirements or achieve multifunctional applications. At the same time, circularly polarized antennas have also been widely used because of their unique advantages in overcoming multipath fading, anti-rain and fog interference, etc.

[0003] Currently, traditional dual-band antennas usually adopt the method of combining multiple independent antennas to achieve dual-band operation. However, there are the following defects: 1. It not only increases the volume and weight of the system, but also causes mutual interference between antennas, reducing the integrity of the system; 2. When the existing circularly polarized antenna design realizes dual-band common-aperture operation, there are problems such as complex structure, high design difficulty, and high cost.

[0004] Some traditional antennas introduce a frequency selective surface (FSS). The FSS can selectively transmit electromagnetic waves of different frequencies, thereby realizing the dual-band function. However, the FSS will introduce insertion loss, reducing the radiation efficiency of the antenna and resulting in weakened signal intensity; the design and manufacturing complexity of the FSS is relatively high, which also increases the cost and manufacturing difficulty of the antenna. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention proposes a dual-band common-aperture circularly polarized reflector antenna, which realizes the functions of high-frequency reflection and low-frequency grounding through a unique reflector structure multiplexing technology, and successfully realizes common-aperture integration without the need for FSS.

[0006] A dual-band common-aperture circularly polarized reflector antenna includes a metal reflector, a high-frequency helical antenna, a low-frequency loop dipole array, a dielectric column, a coaxial cable, and an equal-amplitude and in-phase power divider; The high-frequency helical antenna is suspended and fixed on the metal reflector through three dielectric columns, and the radiation direction points to the reflector antenna; The low-frequency loop dipole array is circularly distributed with the center of the metal reflector as the center of the circle, and the physical rotation angles are 0°, 90°, 180°, and 270° in sequence, and circular polarization is achieved through feeding by an equal-amplitude and in-phase power divider; The coaxial cable serves as the feeding connection line of the high-frequency helical antenna.

[0007] Further, for the dual-band common-aperture circularly polarized reflector antenna, the metal reflector is a parabolic structure, and the aperture of the metal reflector is limited to D, and the focal length ; The material of the metal reflector is an aluminum alloy plate, and the parabolic surface is chemically silver-plated, and the aperture accuracy meets ; Among them, represents the wavelength of the high-frequency band.

[0008] Furthermore, for the dual-band common-aperture circularly polarized reflector antenna, the diameter of the spiral part of the high-frequency band spiral antenna is , and the pitch is .

[0009] Furthermore, for the dual-band common-aperture circularly polarized reflector antenna, the high-frequency band spiral antenna further includes a base, a radio frequency connector, a spiral antenna, and a dielectric material; The high-frequency band spiral antenna prints the spiral antenna on the dielectric material by means of dielectric etching; The high-frequency band spiral antenna is fixed on the base, and the radio frequency connector is installed on the back of the base.

[0010] Furthermore, for the dual-band common-aperture circularly polarized reflector antenna, the coaxial cable is embedded in the dielectric column and extends to connect the radio frequency connector; The coaxial cable includes a radio frequency connector for the high-frequency antenna; The coaxial cable is connected through the radio frequency connector for the high-frequency antenna and an equal-amplitude and in-phase power divider.

[0011] Furthermore, for the dual-band common-aperture circularly polarized reflector antenna, the radiation unit of the low-frequency band loop dipole array is composed of 4 half-wave dipoles, and the length of each dipole is , distributed in a loop, and the height from the metal reflector is , with the metal reflector as the ground plane; The represents the wavelength of the low-frequency band.

[0012] Furthermore, for the dual-band common-aperture circularly polarized reflector antenna, the half-wave dipole is printed on a low-dielectric constant substrate with a thickness of .

[0013] Furthermore, for the dual-band common-aperture circularly polarized reflector antenna, the equal-amplitude and in-phase power divider adopts a microstrip line structure, and the insertion loss is <0.5 dB; The back of the metal reflector is the back cavity of the equal-amplitude and in-phase power divider.

[0014] Furthermore, for the dual-band common-aperture circularly polarized reflector antenna, the equal-amplitude and in-phase power divider includes a radio frequency connector for the low-frequency antenna, a coaxial line, an outer conductor, and a cover plate; The cover plate is the base of the reflector antenna; The radio frequency connector for the high-frequency antenna and the radio frequency connector for the low-frequency antenna are connected; The input end of the equal-amplitude and in-phase power divider is connected to the low-frequency antenna RF connector.

[0015] Furthermore, for the dual-band common-aperture circularly polarized reflector antenna, the equal-amplitude and in-phase power divider is connected and fed to the low-frequency circular dipole array through a coaxial cable, and the outer conductor supports the low-frequency circular dipole array.

[0016] The beneficial effects of the present invention are as follows: 1. Dual-band common-aperture operation: It can simultaneously realize the transceiver of circularly polarized signals in two different frequency bands. Through the common-aperture design, it avoids the problems of large volume and mutual interference caused by using multiple independent antennas, effectively reduces the volume and weight of the antenna system, and improves the integration of the system; 2. Excellent circular polarization characteristics: The helical antenna is used as the feed source in the high-frequency band, and the four dipole antennas are rotated and fed in the low-frequency band to achieve more advantageous circular polarization characteristics, having better anti-interference ability and signal transmission quality in applications such as satellite communication and radar detection; 3. Simple structure and low design cost: The antenna structure is relatively simple, without the need for complex circuit and structure design, reducing the design and manufacturing costs. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of the dual-band common-aperture circularly polarized reflector antenna.

[0018] Figure 2 It is an exploded view of the dual-band common-aperture circularly polarized reflector antenna.

[0019] Figure 3 It is a schematic structural diagram of the high-frequency helical antenna.

[0020] Figure 4 It is a schematic structural diagram of the equal-amplitude and in-phase power divider.

[0021] In the figure, 1 - metal reflector, 2 - high-frequency helical antenna, 3 - low-frequency circular dipole array, 4 - dielectric column, 5 - coaxial cable, 6 - equal-amplitude and in-phase power divider; 2_1 - base, 2_2 RF connector, 2_3 - helical antenna, 2_4 - dielectric material, 5_1 - high-frequency antenna RF connector, 6_1 - low-frequency antenna RF connector, 6_2 - coaxial cable, 6_3 - outer conductor, 6_4 - cover plate. Detailed Embodiments

[0022] The present invention will be further described, but the protection scope of the present invention is not limited to the following.

[0023] Specific Embodiment 1 As shown in the attached Figures 1 to 4As shown in the figure, the antenna structure of a dual-band common-aperture circularly polarized reflector antenna 1. Metal reflector 1: The metal reflector 1 adopts a parabolic structure. According to the aperture D restricted by technical specifications and the focal length , the gain in the high-frequency band is approximately ; is the aperture efficiency, generally between 0.5 and 0.7; is the wavelength in the high-frequency band; The parabolic structure can reflect and converge the electromagnetic waves radiated by the feed, thereby improving the gain of the antenna. By reasonably designing the parameters, the gain of the antenna can be effectively improved, enhancing the radiation ability of the signal. In satellite communication, a high-gain antenna can ensure that the signal maintains a strong intensity during long-distance transmission, thus achieving stable communication and effectively converging high-frequency signals; For the low-frequency band, the metal reflector 1 not only serves as a reflection structure but also functions as a ground plane. In order to suppress the backward radiation, improve the radiation efficiency of the antenna, effectively concentrate the electromagnetic energy in the low-frequency band in front of the antenna for radiation, reduce the waste of energy, and improve the overall performance of the antenna, the multiplexing design of the metal reflector 1 can achieve efficient operation in the dual-band without increasing excessive structural complexity.

[0024] 2. High-frequency helical antenna 2 As shown in the appendix Figure 3 The high-frequency helical antenna 2 adopts a single-arm helical feed. A helical antenna 2_3 is printed on the dielectric material 2_4 by means of dielectric etching. The helical antenna 2_3 is located at the focal point of the metal reflector 1, and its axis coincides with the symmetry axis of the metal reflector 1, which can effectively radiate the circularly polarized signal in the high-frequency band onto the metal reflector 1 and radiate the signal directionally through the metal reflector 1; The diameter of the helical part of the helical antenna 2_3 , the pitch of the helix , satisfying the axial mode condition .

[0025] Ensure that the antenna generates strong radiation in the axial direction and can effectively radiate circularly polarized waves. Helical antennas are commonly used in fields such as communication and radar. Their radiation characteristics make signal transmission more stable and efficient. Axial ratio: ; The number of turns of the helical antenna; The axial ratio is an important indicator for measuring the circular polarization performance of an antenna. The smaller the axial ratio, the better the circular polarization performance of the antenna. When the axial ratio is less than 3 dB, the antenna can be considered to have good circular polarization performance, which can effectively reduce the polarization loss during signal transmission and improve the signal reception quality. 3. Low-frequency band circular dipole array 3 It is composed of 4 half-wave dipoles, and the length of each half-wave dipole , and they are distributed in a circular pattern above the metal reflector 1. This circular distribution method enhances the directivity of the antenna to a certain extent, making the radiation of the antenna stronger in a specific direction. The height of the half-wave dipole from the metal reflector 1 , and the metal reflector 1 serves as a ground plane here. This structural design can effectively improve the radiation performance of the antenna and increase the efficiency of the antenna. Due to its simple structure and easy fabrication, the half-wave dipole antenna is widely used in various communication systems. The feeding network uses a one-to-four equal-amplitude and in-phase power divider 6. The rotation angles of the half-wave dipoles are 0°, 90°, 180°, and 270° in sequence, so that the radiation fields of the four dipoles are superimposed on each other to form a specific radiation pattern. Axial ratio: ; When , the axial ratio meets the condition of being less than or equal to 3 dB, indicating that the antenna has good circular polarization performance in the low-frequency band and can effectively receive and transmit circular polarization signals. The equal-amplitude and in-phase power divider 6 antenna feeding network distributes the input signal power proportionally to each output port to ensure that each half-wave dipole can obtain an excitation signal with the same amplitude and phase, thus guaranteeing the radiation performance of the antenna.

[0026] Specific embodiment 2 is as shown in the appendix Figures 1 to 4 An optimization method for a dual-band common-aperture circular polarization reflector antenna 1. Fabrication of the metal reflector 1 The metal reflector 1 selects aluminum alloy plate as the base material. Aluminum alloy is widely used in the manufacturing field of antenna reflectors due to its advantages such as light weight, high strength, and easy processing and forming. In the aerospace field, the requirement for equipment lightweight is extremely high. The lightweight characteristic of the aluminum alloy material enables the antenna to reduce the overall equipment weight while meeting the performance requirements and improve the operation efficiency of the equipment. To improve the electrical performance of the reflector, silver plating treatment is carried out on the surface of the aluminum alloy plate. Silver has excellent electrical conductivity and low surface resistance. The silver-plated reflector can reflect electromagnetic waves more effectively, reduce signal transmission loss, and improve the radiation efficiency of the antenna. In electronic communication equipment, signal transmission loss directly affects communication quality. Through silver plating treatment, the loss can be significantly reduced to ensure stable signal transmission. During the processing, strictly control the aperture accuracy of the reflector to meet , a high-precision aperture can ensure that the reflector accurately converges and reflects electromagnetic waves according to the design requirements, thereby improving the gain and directivity of the antenna. If the aperture accuracy is insufficient, it will cause deviations in the reflection and convergence of electromagnetic waves, thereby reducing the performance of the antenna and affecting the reliability of communication. 2. Printing of the high-frequency helical antenna 2 As shown in the appendix Figure 2 , the high-frequency helical antenna 2 is realized by using the method of printing a helical structure on a dielectric column. Compared with the traditional metal wire winding scheme, it is more conducive to controlling the processing accuracy, and the structure is not easily deformed, and the performance is more reliable. The high-frequency helical antenna 2 uses three dielectric columns 4 for suspended fixation. The three dielectric columns 4 form a 120° angle with each other. The dielectric column 4 needs to use a low-loss dielectric to reduce the interference to the low-frequency array. The high-frequency helical antenna 2 is fed through a coaxial cable 5 extending from the back of the metal reflector 1. A hollow is made on one of the three dielectric columns, and the coaxial cable 5 is embedded in the hollow part and extends to the helical antenna 2_ Base of 3 2 _1. The dielectric column 4 embedded with the cable needs to be reasonably placed, directly above the gap between the four half-wave dipoles, and avoid being directly above a certain dipole antenna to reduce the interference to the radiation performance of the low-frequency antenna.

[0027] 3. Integration of the low-frequency loop dipole array 3 The radiation unit of the low-frequency loop dipole array 3 is a half-wave dipole, which is printed on an FR4 substrate. The thickness of the FR4 substrate , the FR4 substrate is a commonly used printed circuit board material, which has good electrical insulation performance, mechanical strength and processing performance, and can provide stable support and electrical isolation for the half-wave dipole. In electronic devices, the FR4 substrate is widely used in the production of various circuit boards, and its stable performance can ensure the normal operation of the circuit. The equal-amplitude and in-phase power divider 6 adopts a microstrip line structure with a characteristic impedance Z0 = 50Ω, and achieves good impedance matching with other components to ensure the efficient transmission of signals. In radio frequency and microwave circuits, if the impedance is not matched, it will cause signal reflection and reduce the signal transmission efficiency. The insertion loss of the equal-amplitude and in-phase power divider 6 is <0.5dB. A lower insertion loss means that the power divider consumes less energy when distributing the signal power, and can ensure the strength and quality of the signal.

[0028] The output end of the equal-amplitude and in-phase power divider 6 is a coaxial line 6_2, which passes through the metal reflector 1 from the back of the metal reflector 1 and feeds the half-wave dipole. The outer conductor 6_3 of the coaxial line 6_2 also serves as a support column for the half-wave dipole, playing a role in fixing the half-wave dipole.

[0029] 4. Common Aperture Isolation Optimization In the design of a common aperture antenna, the mutual coupling between high - and low - frequency signals will seriously affect the performance of the antenna. By reasonably setting the distance between the high - and low - frequency feeders, the influence of mutual coupling can be reduced. Through simulation analysis and experimental verification, the distance between the high - and low - frequency feeders is determined , when the feeder distance reaches this value, the mutual interference between high - and low - frequency signals is significantly reduced, the performance of the antenna is significantly improved, the mutual coupling between high - and low - frequency signals is effectively reduced, and the reliability and stability of the antenna are improved. Material optimization is also one of the steps for common aperture isolation optimization. Using a substrate with a low dielectric constant for the half - wave dipole, such as the common FR4 substrate, can reduce the scattering of high - frequency signals, so that when the high - frequency signal passes through the substrate, the energy loss is small and the scattering effect is effectively suppressed.

[0030] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above - mentioned embodiments. What is described in the above - mentioned embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A dual-band common-aperture circularly polarized reflector antenna, characterized in that: It includes a metal reflector (1), a high-frequency helical antenna (2), a low-frequency loop dipole array (3), a dielectric column (4), a coaxial cable (5), and an equal-amplitude and in-phase power divider (6); The high-frequency helical antenna (2) is suspended and fixed on the metal reflector (1) by three dielectric columns (4), and the radiation direction points to the reflector antenna; The low-frequency loop dipole array (3) is circularly distributed with the center of the metal reflector (1) as the center of the circle, and the physical rotation angles are 0°, 90°, 180°, and 270° in sequence, and circular polarization is achieved through feeding by the equal-amplitude and in-phase power divider (6); The coaxial cable (5) serves as the feeding connection line of the high-frequency helical antenna (2).

2. The dual-band common-aperture circularly polarized reflector antenna according to claim 1, wherein: The metal reflecting surface (1) is a parabolic structure, and the aperture of the metal reflecting surface (1) is limited to D, and the focal length ; The material of the metal reflector surface (1) is an aluminum alloy plate, and the parabolic surface is chemically silver-plated, and the aperture accuracy meets ; Among them, represents the wavelength of the high-frequency band.

3. The dual-band common-aperture circularly polarized reflector antenna according to claim 2, wherein: The diameter of the spiral part of the high-frequency band spiral antenna (2) , and the pitch .

4. The dual-band common-aperture circularly polarized reflector antenna according to claim 1, characterized in that: The high-frequency helical antenna (2) further includes a base (2_1), a radio frequency connector (2_2), a helical antenna (2_3), and a dielectric material (2_4); The high-frequency helical antenna (2) prints the helical antenna (2_3) on the dielectric material (2_4) by means of dielectric etching; The high-frequency helical antenna (2) is fixed on the base (2_1), and the radio frequency connector (2_2) is installed on the back of the base (2_1).

5. The dual-band common-aperture circularly polarized reflector antenna according to claim 4, wherein: The coaxial cable (5) is embedded in the dielectric column (4) and extends to connect to the radio frequency connector (2_2); The coaxial cable (5) includes a high-frequency antenna radio frequency connector (5_1); The coaxial cable (5) is connected through the high-frequency antenna radio frequency connector (5_1) and the equal-amplitude and in-phase power divider (6).

6. The dual-band co-aperture circularly polarized reflector antenna according to claim 1, wherein: The radiation element of the low-frequency band loop dipole array (3) is composed of 4 half-wave dipoles, and the length of each dipole , is circularly distributed, and the height from the metal reflector (1) is , and the metal reflector (1) is used as a ground plane; The said represents the wavelength in the low frequency band.

7. The dual-band common-aperture circularly polarized reflector antenna according to claim 6, characterized in that: The half-wave dipole is printed on a low dielectric constant substrate with a thickness of .

8. The dual-band common-aperture circularly polarized reflector antenna according to claim 1, wherein: The equal-amplitude and in-phase power divider (6) adopts a microstrip line structure with an insertion loss <0.5 dB; The back of the metal reflector (1) is the back cavity of the equal-amplitude and in-phase power divider (6).

9. The dual-band common-aperture circularly polarized reflector antenna according to claim 6, wherein: The equal-amplitude and in-phase power divider (6) includes a low-frequency antenna radio frequency connector (6_1), a coaxial line (6_2), an outer conductor (6_3), and a cover plate (6_4); The cover plate (6_4) is the base of the reflector antenna; The high-frequency antenna radio frequency connector (5_1) is connected to the low-frequency antenna radio frequency connector (6_1); The input end of the equal-amplitude and in-phase power divider (6) accesses the low-frequency antenna radio frequency connector (6_1).

10. The dual-band common-aperture circularly polarized reflector antenna according to claim 9, characterized in that: The equal-amplitude and in-phase power divider (6) is connected and fed to the low-frequency loop dipole array (3) through the coaxial line (6_2), and the outer conductor (6_3) supports the low-frequency loop dipole array (3).

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