Dual-frequency circularly polarized combined antenna

Abstract

The utility model discloses a dual-frequency circularly polarized combined antenna, which comprises a metal reflecting plate, a high-frequency circularly polarized radiation unit and a low-frequency wide-beam radiation unit, the high-frequency circularly polarized radiation unit and the low-frequency wide-beam radiation unit share the same reflecting plate, and the high-frequency circularly polarized radiation unit is positioned above the low-frequency wide-beam radiation unit. According to the utility model, the embedded orthogonal dipole pair is adopted, so that the high-frequency-band axial ratio bandwidth breaks through the limitation of the traditional single-feed microstrip antenna, the relative bandwidth with the actually measured axial ratio less than or equal to 3dB reaches 18.7%, and the Beidou third-generation B1C / B2a frequency band requirement can be completely covered. The nickel-chromium alloy films evaporated on the upper and lower surfaces of the dielectric plate effectively inhibit interlayer crosstalk, the cross polarization ratio is improved to be greater than 15dB, and the dual-band radiation purity is ensured.

Description

Technical Field

[0001] This utility model relates to the field of antenna technology, and more specifically, to a dual-frequency circularly polarized combined antenna. Background Technology

[0002] With the continuous development and popularization of wireless communication technology, wireless communication has become one of the most widely used communication methods in life. In wireless communication, the antenna, as the signal transmission device of the wireless communication system, affects the communication quality and stability of the wireless communication system. As a special type of antenna, the circularly polarized antenna can receive and radiate circularly polarized waves, thus possessing strong anti-interference capabilities.

[0003] Traditional dual-band circularly polarized antennas have the following drawbacks:

[0004] Bandwidth limitation: The axial ratio bandwidth of single-fed stacked microstrip antennas is generally <5%, which is difficult to meet the signal requirements of Beidou-3 B1C / B2a.

[0005] Narrow beamwidth: A typical microstrip antenna has a 3dB beamwidth of only 60°~80°, which cannot cover large-angle incident signals from low-speed mobile terminals;

[0006] Structural fragility: Conventional plastic supports are prone to resonant frequency drift under vibration, leading to a deterioration of the standing wave ratio (SWR) > 2.5;

[0007] Volume redundancy: The dual-band independent reflective cavity design makes the overall height reach λ0 / 2 (λ0 is the low-frequency wavelength), which does not conform to the trend of compact vehicle equipment.

[0008] How to solve the technical problems existing in the above-mentioned technologies has become an urgent issue for technicians in this field. Utility Model Content

[0009] In view of the problems existing in the prior art, the purpose of this utility model is to provide a dual-frequency circularly polarized combined antenna, which aims to solve the problems mentioned in the background art.

[0010] To solve the above problems, the present invention adopts the following technical solution:

[0011] A dual-frequency circularly polarized combined antenna includes a metal reflector, a high-frequency circularly polarized radiating element, and a low-frequency wide-beam radiating element. The high-frequency circularly polarized radiating element and the low-frequency wide-beam radiating element share the same metal reflector, and the high-frequency circularly polarized radiating element is located above the low-frequency wide-beam radiating element.

[0012] Furthermore, the high-frequency circularly polarized radiation unit includes a metal connecting post, a dielectric plate, a first orthogonal dipole, and a second orthogonal dipole. The dielectric plate is connected to a metal reflector via the metal connecting post. Both the first and second orthogonal dipoles are embedded in the dielectric plate, with the first orthogonal dipole located above the second orthogonal dipole. A coaxial cable is connected between the dielectric plate and the metal reflector. The first and second orthogonal dipoles are connected to the coaxial cable, and the bottom end of the coaxial cable extends out of the bottom surface of the metal reflector.

[0013] Preferably, the medium plate is fixed to the top of the metal connecting column by titanium alloy anti-loosening screws.

[0014] Furthermore, the low-frequency wide-beam radiation unit includes a support column and an inverted-F antenna unit. There are four support columns and four inverted-F antenna units. Each inverted-F antenna unit is mounted on the top of a metal reflector via a support column. Each inverted-F antenna unit and the metal reflector are connected by a feed electrode.

[0015] Preferably, each of the inverted-F antenna elements is fixed to the top of the corresponding support column by titanium alloy anti-loosening screws.

[0016] Furthermore, each of the inverted F antenna elements is arranged at the vertices of a square, with the spacing between adjacent elements being 0.9 times the low-frequency wavelength, and the phase difference between adjacent elements increasing by 90° sequentially.

[0017] Preferably, a nickel-chromium alloy thin film is deposited on the upper and lower surfaces of the dielectric substrate.

[0018] As a preferred option, a rectangular parasitic patch is added above the metal reflector.

[0019] Preferably, an adjustable capacitor is provided at the root of the inverted-F antenna unit, with an adjustment range of 0.5-2pF.

[0020] Preferably, the support column is filled with silicone rubber particles.

[0021] Compared with existing technologies, this utility model provides a dual-frequency circularly polarized combined antenna, which has the following advantages:

[0022] 1. Employing embedded orthogonal dipole pairs enables the high-frequency axial ratio bandwidth to break through the limitations of traditional single-fed microstrip antennas. The measured relative bandwidth reaches 18.7% with an axial ratio ≤3dB, fully covering the BeiDou-3 B1C / B2a frequency band requirements. The nickel-chromium alloy thin film vapor-deposited on the upper and lower surfaces of the dielectric substrate effectively suppresses interlayer crosstalk, improving the cross-polarization ratio by >15dB and ensuring dual-band radiation purity.

[0023] 2. The inverted-F antenna elements are precisely arranged at the vertices of a square, and with the adjacent elements excited in a 90° phase progression, an omnidirectional radiation pattern is formed. Through electromagnetic coupling tuning with a rectangular parasitic patch, the 3dB beamwidth in the low-frequency band is extended to 120°, which is 56% higher than that of traditional microstrip antennas, significantly enhancing the multipath signal acquisition capability of low-speed mobile terminals in complex terrain.

[0024] 3. The viscoelastic material filled inside the support column can attenuate random vibration response by 70%, avoid the deterioration of standing wave ratio caused by resonance, and ensure the long-term reliability of vehicle-mounted equipment;

[0025] 4. Through the integrated design of high-frequency circularly polarized radiation units and low-frequency wide-beam radiation units, the overall height is compressed to λ0 / 4.5 (λ0 is the low-frequency wavelength), and the volume is reduced by more than 60%. The adjustable capacitor (0.5-2pF) integrated at the base of the support column enables tool-less impedance matching, improving debugging efficiency by 3 times and meeting the needs of rapid deployment in confined spaces. Attached Figure Description

[0026] Figure 1 This is a perspective view of the present utility model;

[0027] Figure 2 This is a second-view perspective perspective view of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of this utility model after the medium plate is removed;

[0029] Figure 4 This is an exploded view of the present invention;

[0030] Figure 5 Gain pattern of low-frequency wide-beam radiating element

[0031] Figure 6 This is the gain pattern of a high-frequency circularly polarized radiating element.

[0032] Explanation of the labels in the diagram:

[0033] 1. Metal reflector; 2. High-frequency circularly polarized radiating unit; 201. Metal connecting post; 202. Dielectric substrate; 203. First orthogonal dipole; 204. Second orthogonal dipole; 3. Coaxial cable; 4. Low-frequency wide-beam radiating unit; 401. Support post; 402. Inverted-F antenna unit; 403. Feed electrode; 5. Titanium alloy anti-loosening screw. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0035] Please see Figures 1 to 6 A dual-band circularly polarized antenna is disclosed. The antenna includes a metal reflector 1, a high-frequency circularly polarized radiating element 2, and a low-frequency wide-beam radiating element 4. The high-frequency circularly polarized radiating element 2 and the low-frequency wide-beam radiating element 4 share the same metal reflector 1, with the high-frequency circularly polarized radiating element 2 positioned above the low-frequency wide-beam radiating element 4. Its core design lies in achieving dual-band performance optimization and structural compactness through conformal integration of the high-frequency circularly polarized radiating element 2 and the low-frequency wide-beam radiating element 4.

[0036] The metal reflector 1 serves as the basic support platform and is made of aluminum-magnesium alloy sheet with a thickness of 0.8mm. The surface is anodized to enhance corrosion resistance. Four evenly distributed metal connecting posts 201 are provided on the top of the metal reflector 1 for fixing the high-frequency circularly polarized radiation unit 2; a coaxial cable 3 through hole is reserved at the bottom to ensure the sealing of the feed line.

[0037] The high-frequency circularly polarized radiation unit 2 includes a metal connecting post 201, a dielectric substrate 202, a first orthogonal dipole 203, and a second orthogonal dipole 204. The dielectric substrate 202 is made of Rogers RT / duroid 5880 material with a dielectric constant ε_r = 2.2 and a thickness of 0.8 mm. It is vertically mounted to the top of the metal connecting post 201 using titanium alloy anti-loosening screws 5. The first orthogonal dipole 203 and the second orthogonal dipole 204 are embedded inside the dielectric substrate 202 in a ±45° cross configuration, with the first orthogonal dipole 203 positioned above the second orthogonal dipole 204, forming a spatially orthogonal electromagnetic field. A coaxial cable 3 passes through the bottom surface of the metal reflector 1, with its inner conductor welded to the feed terminals of the two dipoles, and its outer conductor short-circuited to the metal reflector 1, forming a complete signal loop.

[0038] The low-frequency wide-beam radiating element 4 includes four inverted-F antenna elements 402, which are symmetrically arranged at the vertices of a square on top of the metal reflector 1. Each inverted-F antenna element 402 is vertically fixed by a titanium alloy support column 401 with a diameter of Φ=3mm, and the spacing between adjacent elements is precisely controlled within 0.9 times the low-frequency wavelength. The feed electrode 403 adopts a gold-plated elastic contact design, with one end connected to the root of the inverted-F antenna element 402 and the other end forming a low-impedance contact with the metal reflector 1. Notably, each support column 401 is filled with silicone rubber particles, utilizing the damping properties of the viscoelastic material to absorb mechanical vibration energy.

[0039] As a preferred option, a nickel-chromium alloy thin film with a thickness of 3μm is deposited on the upper and lower surfaces of the dielectric substrate 202 to form an electromagnetic shielding layer, which effectively isolates electromagnetic coupling between layers, with a measured isolation degree >25dB.

[0040] As another preferred option, a rectangular copper foil patch with a size of 0.6λ_l×0.4λ_l (not shown in the figure) is added above the metal reflector 1 to extend the low-frequency beamwidth through electromagnetic induction.

[0041] Preferably, a 0.5-2pF miniature adjustable capacitor is connected in series at the root of the inverted-F antenna unit 402, and the matching state can be adjusted in real time by an external knob.

[0042] Table 1. Effect Verification

[0043] project Traditional structure This utility model Indicator range Axial ratio bandwidth (@AR<3dB) 4.2%@1.575GHz 18.7%@1.575GHz +345% 3dB beamwidth 78°@1.2GHz 122°@1.2GHz +56% Volume (excluding support frame) φ120×35mm³ φ90×22mm³ -60% Random vibration MTBF 800h@5grmsw 3500h@5grmsw +337% Power capacity 50W (continuous) 200W (pulse) +300%

[0044] Working principle

[0045] During operation, the high-frequency circularly polarized radiation unit 2 generates electromagnetic waves with a 90° phase difference through orthogonal dipole pairs, which are then calibrated by a serpentine delay line feed network to form pure circularly polarized waves. The low-frequency wide-beam radiation unit 4 constructs an omnidirectional coverage field pattern based on the spatial phase progression relationship of the four-element array. When the equipment is in a vibration environment, the silicone rubber particles dissipate mechanical energy through molecular friction to prevent resonant frequency drift. The special thread design of the titanium alloy anti-loosening screw 5 can maintain stable preload under long-term vibration.

[0046] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model based on the technical solution and its improved concept should be covered within the protection scope of the present utility model.

Claims

1. A dual-band circularly polarized combined antenna, characterized in that: It comprises a metal reflecting plate (1), a high-frequency circularly polarized radiation unit (2) and a low-frequency wide-beam radiation unit (4), the high-frequency circularly polarized radiation unit (2) and the low-frequency wide-beam radiation unit (4) share the same metal reflecting plate (1), and the high-frequency circularly polarized radiation unit (2) is located above the low-frequency wide-beam radiation unit (4).

2. The dual-band circularly polarized combined antenna according to claim 1, characterized in that: The high-frequency circularly polarized radiation unit (2) comprises a metal connecting column (201), a dielectric plate (202), a first orthogonal dipole (203) and a second orthogonal dipole (204), the dielectric plate (202) is connected with the metal reflecting plate (1) through the metal connecting column (201), the first orthogonal dipole (203) and the second orthogonal dipole (204) are embedded in the dielectric plate (202), and the first orthogonal dipole (203) is located above the second orthogonal dipole (204), a coaxial cable (3) is connected between the dielectric plate (202) and the metal reflecting plate (1), the first orthogonal dipole (203) and the second orthogonal dipole (204) are connected with the coaxial cable (3), and the bottom end of the coaxial cable (3) penetrates out of the bottom surface of the metal reflecting plate (1).

3. The dual-band circularly polarized combined antenna according to claim 2, characterized in that: The dielectric plate (202) is fixed to the top end of the metal connecting column (201) through a titanium alloy anti-loosening screw (5).

4. The dual-band circularly polarized combined antenna according to claim 2, characterized in that: The low-frequency wide-beam radiation unit (4) comprises a support column (401) and a inverted F antenna unit (402), the support column (401) and the inverted F antenna unit (402) are both provided with four, each inverted F antenna unit (402) is installed on the top of the metal reflecting plate (1) through the support column (401), and each inverted F antenna unit (402) and the metal reflecting plate (1) are connected with a feeding electrode (403).

5. The dual-band circularly polarized combined antenna according to claim 4, characterized in that: Each inverted F antenna unit (402) is fixed to the top end of the corresponding support column (401) through a titanium alloy anti-loosening screw (5).

6. The dual-band circularly polarized combined antenna according to claim 4, characterized in that: Each inverted F antenna unit is arranged according to the square vertex, the interval between adjacent units is 0.9 times the low-frequency wavelength, and the phase difference between adjacent units is increased by 90° in turn.

7. The dual-band circularly polarized combined antenna according to claim 4, characterized in that: A nickel-chromium alloy thin film is evaporated on the upper and lower surfaces of the dielectric plate (202).

8. The dual-band circularly polarized combined antenna according to claim 4, characterized in that: A rectangular parasitic patch is additionally arranged above the metal reflecting plate (1).

9. The dual-band circularly polarized combined antenna according to claim 4, characterized in that: An adjustable capacitor is arranged at the root of the inverted F antenna unit (402), and the adjustment range is 0.5-2 pF.

10. The dual-band circularly polarized combined antenna according to claim 4, characterized in that: The support column (401) is filled with silicone rubber particles.

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