A dual-band common-aperture circularly polarized reflector antenna

Abstract

The present invention discloses a dual-band co-aperture circularly polarized reflector antenna, comprising a metal reflector, a high-band helical antenna, a low-band annular dipole array, a dielectric column, a coaxial cable, and a constant-amplitude co-phase power divider. The high-band helical antenna is suspended and fixed on the metal reflector via three dielectric columns, with its radiation direction pointing toward the reflector antenna. The low-band annular dipole array is arranged in a circular pattern with the center of the metal reflector as the center, with physical rotation angles of 0°, 90°, 180°, and 270°, respectively. Circular polarization is achieved by feeding the constant-amplitude co-phase power divider. The coaxial cable serves as the feed connection line for the high-band helical antenna. The present invention utilizes reflector structure multiplexing technology to achieve high-frequency reflection and low-frequency grounding, successfully achieving co-aperture integration without the need for FSS. Reasonable spatial allocation is used to achieve port isolation between high and low frequencies, ensuring that each circularly polarized pattern achieves 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 communications and radar technology, antennas are often required to operate simultaneously in two different frequency bands to meet different communication needs or achieve multi-functional applications. Circularly polarized antennas have also been widely used due to their unique advantages in overcoming multipath fading and resisting rain and fog interference.

[0003] Currently, traditional dual-band antennas typically use a combination of multiple independent antennas to achieve dual-band operation. However, this has the following drawbacks:

[0004] 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;

[0005] 2. The existing circularly polarized antenna design has problems such as complex structure, difficult design and high cost when achieving dual-band co-aperture operation.

[0006] Some traditional antennas incorporate frequency selective surfaces (FSSs), which can selectively transmit electromagnetic waves of different frequencies, thereby achieving dual-band functionality. However, FSSs introduce insertion loss, reducing the antenna's radiation efficiency and resulting in weakened signal strength. The design and manufacturing complexity of FSSs is high, increasing the cost and difficulty of antenna production. Summary of the Invention

[0007] To solve the above technical problems, the present invention proposes a dual-band co-aperture circularly polarized reflector antenna. Through a unique reflector structure multiplexing technology, it realizes the functions of high-frequency reflection and low-frequency grounding, and successfully achieves co-aperture integration without the need for FSS.

[0008] A dual-band common-aperture circularly polarized reflector antenna, comprising a metal reflector, a high-frequency helical antenna, a low-frequency annular dipole array, a dielectric column, a coaxial cable, and a constant-amplitude and in-phase power divider;

[0009] The high-frequency helical antenna is suspended and fixed on a metal reflective surface through three dielectric columns, and the radiation direction points to the reflective surface antenna;

[0010] The low-frequency ring dipole array is distributed in a ring with the center of the metal reflector as the center, and the physical rotation angles are 0°, 90°, 180°, and 270°, respectively, and circular polarization is achieved by feeding with an equal-amplitude and in-phase power divider;

[0011] The coaxial cable serves as a feed connection line for the high-frequency band helical antenna.

[0012] Furthermore, in a dual-band common aperture circularly polarized reflector antenna, the metal reflector is a parabolic structure, the metal reflector aperture is limited to D, and the focal length is ;

[0013] The metal reflective surface is made of aluminum alloy plate, and the parabolic surface is chemically silver-plated. The aperture accuracy meets ;

[0014] in, Represents the wavelength of the high frequency band.

[0015] Furthermore, the dual-band common-aperture circularly polarized reflector antenna has a spiral portion with a diameter of , pitch .

[0016] Furthermore, the dual-band co-aperture circularly polarized reflector antenna, the high-frequency band helical antenna further includes a base, a radio frequency connector, a helical antenna, and a dielectric material;

[0017] The high frequency band helical antenna is printed on a dielectric material in a dielectric etching manner to form a helical antenna;

[0018] The high-frequency band helical antenna is fixed on the base, and a radio frequency connector is installed on the back of the base.

[0019] Furthermore, in the dual-band co-aperture circularly polarized reflector antenna, the coaxial cable is embedded in a dielectric column and extended to connect to a radio frequency connector;

[0020] The coaxial cable includes a high frequency antenna radio frequency connector.

[0021] Furthermore, the dual-band co-aperture circularly polarized reflector antenna, the radiation unit of the low-frequency ring dipole array consists of 4 half-wave dipoles, each dipole length , distributed in a ring shape, at a height of , using the metal reflective surface as the ground plane;

[0022] described Represents the low-frequency wavelength.

[0023] Furthermore, the dual-band common-aperture circularly polarized reflector antenna, the half-wave dipole is printed on the thickness on a low dielectric constant substrate.

[0024] Furthermore, in the dual-band co-aperture circularly polarized reflector antenna, the equal-amplitude and co-phase power divider adopts a microstrip line structure with an insertion loss of <0.5dB;

[0025] The back of the metal reflective surface is a back cavity of an equal-amplitude and in-phase power divider.

[0026] Furthermore, in the dual-band co-aperture circularly polarized reflector antenna, the equal-amplitude and co-phase power splitter includes a low-frequency antenna RF connector, a coaxial line, an outer conductor, and a cover plate;

[0027] The cover plate is the base of the reflector antenna.

[0028] Furthermore, in the dual-band co-aperture circularly polarized reflector antenna, the equal-amplitude and co-phase power divider is connected to the low-frequency ring dipole array through a coaxial line for feeding, and the outer conductor supports the low-frequency ring dipole array.

[0029] The beneficial effects of the present invention are:

[0030] 1. Dual-band co-aperture operation: It can simultaneously transmit and receive circularly polarized signals in two different frequency bands. The co-aperture design avoids the bulk and mutual interference problems caused by the use of multiple independent antennas, effectively reducing the size and weight of the antenna system and improving system integration.

[0031] 2. Excellent circular polarization characteristics: The high frequency band adopts a spiral antenna as the feed source, and the low frequency band adopts four dipole antennas as the rotation feed method to achieve more advantageous circular polarization characteristics, which has better anti-interference ability and signal transmission quality in applications such as satellite communications and radar detection;

[0032] 3. Simple structure and low design cost: The antenna structure is relatively simple and does not require complex circuit and structural design, which reduces design and manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural diagram of a dual-band co-aperture circularly polarized reflector antenna.

[0034] Figure 2 This is an exploded diagram of the dual-band co-aperture circularly polarized reflector antenna.

[0035] Figure 3 It is a structural diagram of a high-frequency helical antenna.

[0036] Figure 4 It is a structural diagram of an equal-amplitude and in-phase power divider.

[0037] In the figure, 1-metal reflector, 2-high-band helical antenna, 3-low-frequency ring dipole array, 4-dielectric column, 5-coaxial cable, 6-equal-amplitude and in-phase power divider;

[0038] 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 line, 6_3 - outer conductor, 6_4 - cover. DETAILED DESCRIPTION

[0039] The present invention is further described below, but the protection scope of the present invention is not limited to the following description.

[0040] Specific embodiment 1 As shown in the attached Figures 1 to 4 As shown, the antenna structure of a dual-band common aperture circularly polarized reflector antenna

[0041] 1. Metal reflective surface 1:

[0042] The metal reflective surface 1 adopts a parabolic structure, and the aperture D and focal length are limited according to technical indicators. , then the high frequency gain is approximately

[0043] ;

[0044] is the aperture efficiency, generally between 0.5 and 0.7;

[0045] is the wavelength of the high frequency band;

[0046] The parabolic structure can reflect and converge the electromagnetic waves radiated by the feed source, thereby increasing the gain of the antenna. By rationally designing the parameters, the gain of the antenna can be effectively increased and the radiation capability of the signal can be enhanced. In satellite communications, high-gain antennas can ensure that the signal maintains a strong intensity during long-distance transmission, thereby achieving stable communication and effectively converging high-frequency signals.

[0047] For the low-frequency band, the metal reflective surface 1 is not only a reflective structure, but also acts as a ground plane. In order to suppress back radiation, improve the radiation efficiency of the antenna, and effectively concentrate the electromagnetic energy in the low-frequency band to radiate in front of the antenna, reduce energy waste, and improve the overall performance of the antenna, the reuse design of the metal reflective surface 1 can achieve efficient dual-band operation without increasing too much structural complexity.

[0048] 2. High frequency helical antenna 2

[0049] As attached Figure 3 As shown, the high-frequency helical antenna 2 uses a single-arm helical feed. A helical antenna 2_3 is printed on a dielectric material 2_4 by dielectric etching. The helical antenna 2_3 is located at the focal position of the metal reflective surface 1, and its axis coincides with the symmetry axis of the metal reflective surface 1. It can effectively radiate high-frequency circularly polarized signals onto the metal reflective surface 1 and radiate the signals directionally through the metal reflective surface 1.

[0050] The diameter of the helical portion of the helical antenna 2_3 , the pitch of the helix , meeting the axial mode condition .

[0051] Ensure that the antenna produces strong radiation in the axial direction and can effectively radiate circularly polarized waves. Helical antennas are often used in communications, radar and other fields. Their radiation characteristics make signal transmission more stable and efficient. Axis ratio:

[0052] ;

[0053] The number of turns of the helical antenna;

[0054] 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 3dB, the antenna can be considered to have good circular polarization performance, which can effectively reduce polarization loss during signal transmission and improve signal reception quality.

[0055] 3. Low-frequency ring dipole array 3

[0056] It consists of 4 half-wave dipoles, each half-wave dipole is , distributed in a circular shape above the metal reflective surface 1. The circular distribution enhances the directivity of the antenna to a certain extent, making the antenna radiate more strongly in a specific direction. The half-wave dipole is at a height of The metal reflective surface 1 serves as a ground plane here. The structural design can effectively improve the radiation performance of the antenna and improve the efficiency of the antenna. The half-wave dipole antenna is widely used in various communication systems due to its simple structure and easy production.

[0057] The feeding network uses a one-to-four equal-amplitude in-phase power divider 6. The half-wave dipole rotation angles are 0°, 90°, 180°, and 270°, respectively, so that the radiation fields of the four dipoles are superimposed on each other to form a specific radiation pattern with an axial ratio of:

[0058] ;

[0059] when When , the axial ratio meets the condition of less than or equal to 3dB, indicating that the antenna has good circular polarization performance in the low frequency band and can effectively receive and transmit circularly polarized signals. The antenna feed network of the equal-amplitude and in-phase power divider 6 distributes the input signal power to each output port in equal proportion, ensuring that each half-wave dipole can obtain the excitation signal of the same amplitude and phase, thereby ensuring the radiation performance of the antenna.

[0060] Specific embodiment 2 As shown in the attached Figures 1 to 4 As shown, an optimization method for a dual-band co-aperture circularly polarized reflector antenna

[0061] 1. Processing of metal reflective surface 1

[0062] The metal reflector 1 is made of aluminum alloy sheet material. Aluminum alloy is widely used in the manufacturing of antenna reflectors due to its advantages such as light weight, high strength, and easy processing and forming. In the aerospace field, the requirements for lightweight equipment are extremely high. The lightweight characteristics of aluminum alloy material enable the antenna to meet performance requirements while reducing the weight of the entire equipment and improving the operating efficiency of the equipment.

[0063] In order to improve the electrical performance of the reflective surface, the surface of the aluminum alloy plate is silver-plated. Silver has excellent conductivity and low surface resistance. The silver-plated reflective surface can more effectively reflect electromagnetic waves, reduce signal transmission loss, and improve the radiation efficiency of the antenna. In electronic communication equipment, signal transmission loss directly affects the communication quality. Silver plating can significantly reduce the loss and ensure stable signal transmission.

[0064] During the processing, the aperture accuracy of the reflective surface is strictly controlled to meet A high-precision aperture can ensure that the reflecting surface 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.

[0065] 2. High frequency helical antenna 2 printed

[0066] As attached Figure 2 As shown, the high-frequency helical antenna 2 is realized by printing a spiral structure with dielectric columns. Compared with the traditional metal wire winding solution, it is more conducive to the control of processing accuracy, and the structure is not easily deformed, and the performance is more reliable. The high-frequency helical antenna 2 is suspended and fixed using three dielectric columns 4. The three dielectric columns 4 form a 120° angle with each other. The dielectric columns 4 need to use low-loss dielectrics to reduce interference with the low-frequency array.

[0067] The high-frequency helical antenna 2 is fed by a coaxial cable 5 extending from the back of the metal reflector 1. One of the three dielectric columns is hollowed out, and the coaxial cable 5 is embedded in the hollow part and extends to the helical antenna 2. 3 base 2 The dielectric column 4 embedded in the cable needs to be placed properly, directly above the gaps between the four half-wave dipoles, and avoid being placed directly above a dipole antenna to reduce interference with the radiation performance of the low-frequency antenna.

[0068] 3. Low-frequency ring dipole array 3 integration

[0069] The radiation unit of the low-frequency ring dipole array 3 is a half-wave dipole, which is printed on an FR4 substrate with a thickness of FR4 substrate is a commonly used printed circuit board material with good electrical insulation, mechanical strength and processing performance. It can provide stable support and electrical isolation for half-wave dipoles. In electronic equipment, FR4 substrate is widely used in the production of various circuit boards. Its stable performance can ensure the normal operation of the circuit.

[0070] The equal-amplitude, in-phase power divider 6 adopts a microstrip line structure with a characteristic impedance of Z0 = 50Ω, achieving good impedance matching with other components to ensure efficient signal transmission. In RF and microwave circuits, if the impedance does not match, it will cause signal reflection and reduce signal transmission efficiency. The equal-amplitude, in-phase power divider 6 has an insertion loss of <0.5dB. The lower insertion loss means that the power divider consumes less energy when distributing signal power, which can ensure the strength and quality of the signal.

[0071] The output end of the equal-amplitude and in-phase power divider 6 is a coaxial line 6_2, which passes through the metal reflective surface 1 from the back 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 the role of fixing the half-wave dipole.

[0072] 4. Common-caliber isolation optimization

[0073] In the design of co-aperture antennas, the mutual coupling between high-frequency and low-frequency signals will seriously affect the performance of the antenna. By reasonably setting the spacing between high-frequency and low-frequency feeds, the influence of mutual coupling can be reduced. After simulation analysis and experimental verification, the spacing between high-frequency and low-frequency feeds is determined. When the feed source spacing reaches this value, the mutual interference between high and low frequency signals is significantly reduced, the performance of the antenna is significantly improved, and the mutual coupling between high and low frequency signals is effectively reduced, thereby improving the reliability and stability of the antenna.

[0074] Material optimization is also one of the steps in common-aperture isolation optimization. The half-wave dipole uses a low dielectric constant substrate, such as the common FR4 substrate, which can reduce the scattering of high-frequency signals, so that the high-frequency signal has less energy loss when passing through the substrate, and the scattering effect is effectively suppressed.

[0075] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A dual-band co-aperture circularly polarized reflector antenna, characterized by: It includes a metal reflective surface (1), a high-frequency band helical antenna (2), a low-frequency band annular dipole array (3), a dielectric column (4), a coaxial cable (5), and an equal-amplitude and in-phase power divider (6); The high-frequency band helical antenna (2) is suspended and fixed on the metal reflective surface (1) through three dielectric columns (4), and the radiation direction points to the reflective surface antenna; The low-frequency ring dipole array (3) is distributed in a ring with the center of the metal reflective surface (1) as the center of the circle, and the physical rotation angles are 0°, 90°, 180°, and 270° respectively, and circular polarization is achieved by feeding through the equal-amplitude and in-phase power divider (6); The coaxial cable (5) serves as a feed connection line for the high-frequency band helical antenna (2); The high-frequency band 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 band helical antenna (2) is formed by printing a helical antenna (2_3) on a dielectric material (2_4) by dielectric etching; The high-frequency band helical antenna (2) is fixed on the base (2_1), and a radio frequency connector (2_2) is installed on the back of the base (2_1); The radiation unit of the low-frequency annular dipole array (3) is composed of four half-wave dipoles, each of which has a length of , distributed in a ring shape, at a height of (1) from the metal reflective surface , with the metal reflective surface (1) as the ground plane; described Represents the wavelength of the low frequency band; The equal-amplitude and in-phase power divider (6) comprises 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.

2. The dual-band common-aperture circularly polarized reflector antenna according to claim 1, characterized in that: The metal reflective surface (1) is a parabolic structure, the metal reflective surface (1) has an aperture limit of D, and a focal length of ; The metal reflective surface (1) is made of aluminum alloy plate, and the parabolic surface is chemically silver-plated, and the aperture accuracy meets ; in, Represents the wavelength of the high frequency band.

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

4. The dual-band common-aperture circularly polarized reflector antenna according to claim 1, 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) comprises a high-frequency antenna radio frequency connector (5_1).

5. The dual-band co-aperture circularly polarized reflector antenna according to claim 1, characterized in that: The half-wave dipole is printed on a thickness on a low dielectric constant substrate.

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

7. The dual-band co-aperture circularly polarized reflector antenna according to claim 1, characterized in that: The equal-amplitude and in-phase power divider (6) is connected to the low-frequency-band annular dipole array (3) for power feeding via a coaxial line (6_2), and the outer conductor (6_3) supports the low-frequency-band annular dipole array (3).

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