A dual-band high-gain common-aperture antenna with a large frequency ratio

Abstract

The present invention is a dual-band high-gain common-aperture antenna with a large frequency ratio, which is composed of two dielectric substrates and two feeding structures. The upper dielectric substrate is printed with a periodic metasurface unit structure, which is a partial reflection surface for the high-gain cavity antenna in the low-frequency band and a polarization grating for the folded reflector antenna in the high-frequency band. In the center of the upper surface of the lower dielectric substrate, a microstrip patch antenna for feeding the high-gain cavity antenna is printed, and polarization conversion reflection units in the high-frequency band are printed around it; the lower surface of the lower dielectric substrate serves as a ground plane. The lower side of the dielectric substrate is connected to a standard waveguide, and the folded reflector antenna in the high-frequency band is fed through the waveguide. The dual-band common-aperture antenna provided by the present invention realizes the effect of transmitting and receiving electromagnetic waves in both the Sub-6GHz band and the millimeter-wave band in the 5G communication field, and is a common-aperture antenna with a relatively large frequency ratio.

Description

Technical Field

[0001] The present invention relates to a common-aperture antenna, and particularly to a dual-band high-gain common-aperture antenna with a large frequency ratio. Background Art

[0002] With the advent of the 5G communication era, spectrum resources are continuously expanding towards higher frequency bands. The existing 5G communication systems mainly involve two frequency bands: the Sub-6GHz band and the millimeter-wave band. Since the two frequency bands are far apart, it is usually very difficult to make an antenna work well in both of these two frequency bands. Therefore, the research on multi-band antennas (especially those with a large frequency separation) has attracted wide attention. On the other hand, with the development of antenna technology, some new metamaterial structures have emerged. These metamaterials can often exhibit different performances in different frequency bands, which makes it possible for an antenna to achieve different functions within the same aperture plane. The common-aperture antenna is such a type of antenna that can satisfy multiple antennas to work simultaneously in multiple frequency bands under the same aperture plane, which can greatly reduce the aperture size of the antenna and thus reduce the processing cost of the antenna. Summary of the Invention

[0003] Technical Problem: In order to overcome the deficiencies in the prior art, the present invention provides a dual-band high-gain common-aperture antenna with a large frequency ratio, which solves the problem of realizing antenna common aperture and high gain in both the Sub-6GHz band and the millimeter-wave band (the two frequency bands are far apart) of 5G communication. That is, the dual-band operation and high-gain radiation of the antenna are simultaneously realized by using the same aperture without the need for unit arraying.

[0004] Technical Solution: To solve the above technical problem, the technical solution adopted by the present invention is as follows:

[0005] A dual-band high-gain common-aperture antenna with a large frequency ratio is composed of two dielectric plates and two feeding structures. The upper dielectric plate is printed with a periodic metasurface unit structure, which is a partially reflecting surface for the high-gain cavity antenna in the low-frequency band and a polarization grating for the folded reflector antenna in the high-frequency band. In the center of the upper surface of the lower dielectric plate, a microstrip patch antenna for feeding the high-gain cavity is printed, and polarization conversion reflection units in the high-frequency band are printed around it; the lower surface of the lower dielectric plate serves as a ground plane. A circle of metallized vias is drilled in the center of the lower dielectric plate, and a rectangular notch is left in the center of the microstrip patch antenna and the ground plane respectively. The lower side of this dielectric plate is connected to a standard WR34 waveguide, and the folded reflector antenna in the high-frequency band is fed through the waveguide. The dual-band common-aperture antenna provided by the present invention realizes the effect of being able to transmit and receive electromagnetic waves in both the Sub-6GHz band and the millimeter-wave band in the 5G communication field, and is a common-aperture antenna with a relatively high frequency ratio.

[0006] The periodic metasurface unit structure printed on the upper dielectric substrate is a square ring with a grid structure in the middle. It has the characteristics of a partially reflecting surface in the low-frequency band, can transmit a small part of the electromagnetic wave and reflect most of the electromagnetic wave, and can jointly form a high-gain resonant cavity antenna with the ground plane of the lower dielectric substrate. The microstrip patch antenna printed on the lower dielectric substrate feeds the resonant cavity antenna. The low-frequency electromagnetic wave is reflected back and forth many times in the high-gain resonant cavity, and finally forms a beam with the same phase at the radiation aperture surface and radiates out, greatly improving the gain of the antenna. The metasurface structure has the characteristics of a polarization grating in the high-frequency band, can fully transmit the electromagnetic wave of one polarization mode and fully reflect the electromagnetic wave with orthogonal polarization. The reflection units printed and arranged on the lower dielectric substrate can not only fully reflect the high-frequency electromagnetic wave, but also achieve the effects of polarization conversion and phase compensation, and can jointly form a folded reflector antenna with the polarization grating of the upper dielectric substrate. The standard WR34 waveguide connected to the lower dielectric substrate feeds the folded reflector antenna in the high-frequency band. The electromagnetic wave emitted from the waveguide is fully reflected back when it reaches the polarization grating for the first time. After the polarization conversion and phase compensation of the reflection unit, a plane wave with the same phase can be formed at the radiation aperture surface when it reaches the polarization grating for the second time and radiates out, greatly improving the gain of the antenna.

[0007] The height of the low-frequency resonant cavity satisfies the condition of H=(1 / 2 + n / 2)λ 1 where λ 1 is the free-space wavelength of the electromagnetic wave at the low-frequency center frequency, and n = 0, 1, 2...; the focal ratio of the folded reflector antenna in the high-frequency band satisfies 2H / D = 1 / 2, where D is the diameter length of the antenna aperture surface.

[0008] Beneficial effects: Compared with the prior art, the present invention has the following characteristics.

[0009] 1. Compared with the existing multi-band common-aperture antennas, the present invention eliminates the complex feeding network of the traditional common-aperture antenna, has a smaller profile height, and a simpler structure;

[0010] 2. The present invention forms two types of high-gain antennas through two dielectric substrates, and both the high-gain resonant cavity antenna and the folded reflector antenna can be studied separately, making the dual-band common-aperture antenna have high independence and flexibility in design. In theory, a common-aperture antenna with any frequency ratio can be designed. Description of the Drawings

[0011] Figure 1 is the overall structural schematic diagram of the present invention.

[0012] Figure 2 is the side view of the present invention.

[0013] Figure 3 Schematic diagram of the structure and principle of the low-frequency high-gain resonant cavity antenna of the present invention.

[0014] Figure 4 Schematic diagram of the structure and principle of the high-frequency folded reflector antenna of the present invention.

[0015] Figure 5 Schematic diagram of the structure of the periodic metasurface of the present invention.

[0016] Figure 6 Schematic diagram of the structure of the polarization conversion reflector of the present invention.

[0017] Figure 7 Schematic diagram of the periodic unit structure of the metasurface of the present invention.

[0018] Figure 8 Curve diagram of the reflection coefficient and port isolation of the low-frequency band of the present invention.

[0019] Figure 9 E-plane gain pattern of the low-frequency band of the present invention.

[0020] Figure 10 H-plane gain pattern of the low-frequency band of the present invention.

[0021] Figure 11 Curve diagram of the reflection coefficient and port isolation of the high-frequency band of the present invention.

[0022] Figure 12 E-plane gain pattern of the high-frequency band of the present invention.

[0023] Figure 13 H-plane gain pattern of the high-frequency band of the present invention.

[0024] In the figure: periodic metasurface unit structure 1, microstrip patch antenna 2, polarization conversion reflection unit 3, ground plane 4, standard WR34 waveguide 5. Detailed implementation manners

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] As Figure 1 , 2, as shown in Figures 3, 4, 5, and 6, a dual-band high-gain common-aperture antenna with a large frequency ratio includes two dielectric plates and a standard WR34 waveguide 5. Among them, a periodic metasurface unit structure 1 is printed on the upper dielectric plate; a microstrip patch antenna 2 and a polarization conversion reflection unit 3 are printed on the upper side of the lower dielectric plate, and a ground plane 4 is printed on the lower side of the lower dielectric plate. The ground plane 4 is connected to the standard WR34 waveguide 5. At low frequencies, the periodic metasurface unit structure 1 has the characteristics of a partial reflection surface, which can transmit a small part of the electromagnetic wave and reflect most of the electromagnetic wave, and forms a high-gain resonant cavity antenna with the ground plane 4. The microstrip patch antenna 2 feeds the resonant cavity antenna. The low-frequency electromagnetic wave is reflected back and forth many times in the high-gain resonant cavity, and finally forms a beam with the same phase on the radiation aperture surface and radiates out, greatly improving the gain of the antenna. The periodic metasurface unit structure 1 has the characteristics of a polarization grating in the high-frequency band, which can fully transmit the electromagnetic wave of one polarization mode and fully reflect the electromagnetic wave with orthogonal polarization thereto. The polarization conversion reflection unit 3 printed and arranged on the lower dielectric plate can realize the effects of polarization conversion and phase compensation while fully reflecting the high-frequency electromagnetic wave, and can jointly form a folded reflection array antenna with the polarization grating on the upper dielectric plate. The standard WR34 waveguide 5 connected to the lower dielectric plate feeds the folded reflection array antenna in the high-frequency band. The electromagnetic wave emitted from the waveguide is fully reflected back when it reaches the polarization grating for the first time. After the polarization conversion and phase compensation of the polarization conversion reflection unit 3, a plane wave with the same phase can be formed on the radiation aperture surface when it reaches the polarization grating for the second time and radiates out, greatly improving the gain of the antenna. The height of the low-frequency resonant cavity satisfies the condition of H = (1 / 2 + n / 2)λ 1 , where λ 1 is the free-space wavelength of the electromagnetic wave at the low-frequency center frequency, n = 0, 1, 2...; the focal ratio of the folded reflection array antenna in the high-frequency band satisfies 2H / D = 1 / 2, where D is the diameter length of the antenna aperture surface.

[0027] As Figure 7 shown, the periodic metasurface unit structure 1 printed on the upper dielectric plate is composed of periodic unit structures with a period of P. The unit structure is a square ring with grid-shaped strips. The side length of the square ring is L and the width is s. There are 8 grid-shaped strips in each square ring, the width of each grid-shaped strip is s, and the spacing between adjacent two grid-shaped strips is g. This structure presents the characteristics of a partial reflection surface for low-frequency signals and the characteristics of a polarization grating for high-frequency signals.

[0028] For the convenience of explaining the design process of each structural parameter, the following structural parameters are given: the side length of the square loop of the periodic metasurface structural unit is L = 7.4 mm, the width is s = 0.2 mm, and the period is P = 7.6 mm. The width of each grating bar is s = 0.2 mm, and the distance between two adjacent grating bars is g = 0.6 mm. The center frequency f L of the low frequency is 5.4 GHz, and the distance between the two dielectric plates is approximately H = 30 mm; the center frequency f H of the high frequency is 25 GHz, and the diameters of the two dielectric plates are both D = 120 mm. The height of the low-frequency high-gain resonant cavity satisfies the condition of H ≈ 1 / 2λ 1 , where λ 1 is the free-space wavelength of the electromagnetic wave at the low-frequency center frequency; the focal diameter ratio of the high-frequency folded reflector antenna satisfies 2H / D = 1 / 2, where D is the diameter length of the antenna aperture plane. Select high-frequency simulation software such as HFSS of Ansoft Corporation and Microwave Studio CST of CST Corporation, and simulate on the computer to obtain: as shown in Figure 8 、 Figure 11 the reflection coefficient (S 11 ) curve graphs of the two frequency bands and the port isolation (S 21 ) curve graphs; as shown in Figure 9 、 Figure 10 the E-plane and H-plane gain pattern graphs of the low-frequency band; as shown in Figure 12 、 Figure 13 the E-plane and H-plane gain pattern graphs of the high-frequency band. The curves obtained above are obtained under the given conditions. Similar curves can also be obtained if the structural parameters are changed. If the height of the resonant cavity or the diameter of the aperture plane is further changed, different operating frequency bands and the corresponding antenna gains can be obtained.

[0029] The above is only the preferred embodiment of the present invention. It should be noted that: for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A dual - band high - gain common - aperture antenna with a large frequency ratio, characterized in that: The antenna includes a periodic metasurface unit structure (1) arranged on the upper dielectric substrate, a microstrip patch antenna (2) arranged on the lower dielectric substrate, a polarization - conversion reflection unit (3), a back - plane ground (4), and a standard WR34 waveguide (5) located under the lower dielectric substrate; The periodic metasurface unit structure (1) consists of multiple elements arranged on the upper dielectric substrate to form a periodic metasurface, which acts as a partial reflection surface of a high - gain cavity antenna at low frequencies and as a polarization grating of a folded reflector antenna at high frequencies; The microstrip patch antenna (2) is located at the center of the lower dielectric substrate and feeds the high - gain cavity antenna in the low - frequency band; The polarization - conversion reflection unit (3) is arranged around the microstrip patch antenna (2) on the lower dielectric substrate. The polarization - conversion reflection unit (3) is a rectangular structure, which reflects high - frequency electromagnetic waves and also plays a role in polarization conversion and phase compensation; The back - plane ground (4) is located on the lower surface of the lower dielectric substrate, and the standard WR34 waveguide (5) is connected to the center of the lower surface of the lower dielectric substrate.

2. The dual - band high - gain common - aperture antenna with a large frequency ratio according to claim 1, characterized in that: A plurality of periodic metasurface unit structures (1) are arranged on the upper dielectric substrate along the x - axis and y - axis directions according to a set period length.

3. The dual - band high - gain common - aperture antenna with a large frequency ratio according to claim 1, characterized in that: The polarization - conversion reflection unit (3) is arranged around the microstrip patch antenna (2) on the lower dielectric substrate along directions with an angle of 45° and - 45° with the x - axis according to a set period length.

4. The dual - band high - gain common - aperture antenna with a large frequency ratio according to claim 1, characterized in that: Rectangular notches are left on both the microstrip patch antenna (2) and the back - plane ground (4).

5. The dual - band high - gain common - aperture antenna with a large frequency ratio according to claim 1, characterized in that: The periodic metasurface unit structure (1) is a square ring with a grid - shaped strip in the middle. The high - gain cavity antenna in the low - frequency band and the folded reflector antenna in the high - frequency band share the upper dielectric substrate printed with the periodic metasurface unit structure (1) as the antenna radiation aperture.

6. The dual - band high - gain common - aperture antenna with a large frequency ratio according to claim 1, characterized in that: The microstrip patch antenna (2) is a rectangular structure.

7. The dual - band high - gain common - aperture antenna with a large frequency ratio according to claim 1, characterized in that: The polarization - conversion reflection unit (3) is a rectangular patch rotated 45° around the z - axis.

8. The dual - band high - gain common - aperture antenna with a large frequency ratio according to claim 1, characterized in that: The standard WR34 waveguide (5) is connected to the lower dielectric substrate and feeds the folded reflector antenna in the high - frequency band.

9. The dual - band high - gain common - aperture antenna with a large frequency ratio according to claim 1, characterized in that: The height of the high-gain resonant cavity in the low-frequency band satisfies the condition of H = (1 / 2 + n / 2)λ 1 , where λ 1 is the free-space wavelength of the electromagnetic wave at the low-frequency center frequency, and n = 0, 1, 2...; the focal diameter ratio of the high-frequency folded reflector antenna satisfies 2H / D = 1 / 2, where D is the diameter length of the antenna aperture surface.

10. The dual - band high - gain common - aperture antenna with a large frequency ratio according to claim 1, Characterized in that: The backplane ground plane (4) is made of copper foil material.

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