A broadband dual-polarized metasurface indoor access point antenna

Abstract

The application discloses a broadband dual-polarized metasurface indoor access point antenna, which comprises a first dielectric substrate and a second dielectric substrate, the first dielectric substrate is located above the second dielectric substrate, and an air gap is left between the first dielectric substrate and the second dielectric substrate; a first copper cladding layer is arranged on the upper surface of the first dielectric substrate, a metasurface radiation structure is arranged on the first copper cladding layer, the metasurface radiation structure comprises uniform and non-uniform metasurface units, a gap is left between every two metasurface units, the uniform metasurface units are combined together, and an X-shaped slot is formed to expand the bandwidth; a second copper cladding layer and a third copper cladding layer are arranged on the upper surface and the lower surface of the second dielectric substrate respectively; a plurality of H-shaped feeding slots which are rotationally symmetrical about the center of the second copper cladding layer are arranged on the second copper cladding layer; a first feeding network and a second feeding network are arranged on the third copper cladding layer, and the first feeding network and the second feeding network couple energy to the first copper cladding layer to radiate electromagnetic waves through the H-shaped feeding slots. The antenna has the characteristics of wideband operation, simple structure, low profile and high integration.

Description

Technical Field

[0001] This invention relates to the technical field of communication antennas, and in particular to a broadband dual-polarized metasurface indoor access point antenna. Background Technology

[0002] Metasurface antennas are widely used in wireless communication systems due to their wide bandwidth, low profile, and ease of fabrication. Previous designs focused on the 5G or Wi-Fi bands to improve their coverage. However, with increasing user demands for mobile network coverage, it is often necessary to simultaneously provide good coverage for both 5G and Wi-Fi bands. To achieve both low profile and wide bandwidth, researchers have proposed metasurface antennas capable of generating dual-polarized electromagnetic waves, i.e., broadband dual-polarized metasurface antennas. These designs often focus on independently covering the 5G or Wi-Fi 6 5GHz band, but wider bandwidth antennas often cannot achieve dual polarization due to structural limitations. However, using a dual-polarized antenna that can simultaneously cover the 5G (3.3-5GHz) and Wi-Fi 6 5GHz band (5.17-5.835GHz) can effectively reduce the number of antennas required for indoor coverage and mitigate signal loss caused by polarization mismatch.

[0003] An investigation and understanding of existing technologies was conducted, specifically as follows:

[0004] In 2021, F. Lin et al. proposed a metasurface antenna that utilizes two pairs of straight slots for feeding. By generating radiation at low frequencies through the straight slots, they achieved an extended impedance bandwidth, reaching a relative bandwidth of 25%, which can cover the 5GHz band of Wi-Fi 6. However, it cannot further cover the N77 / N78 / N79 bands of 5G communication systems.

[0005] In 2021, Z. Wang et al. proposed a metasurface-based tripolarized 5G indoor antenna. By constructing two metasurface transmission lines, they realized a tripolarized indoor antenna that can cover the N78 band of 5G communication. However, its bandwidth is relatively narrow, making it difficult to further extend to simultaneously cover the N77 / N78 / N79 bands of 5G communication systems and the 5GHz band of the Wi-Fi 6 protocol.

[0006] In summary, while there is considerable research on broadband indoor antennas in existing works, many are limited by their structural design, only able to cover either the 5G N77 / N78 / N79 bands or the 5GHz band of the Wi-Fi 6 protocol. Therefore, designing a simple and effective broadband dual-polarized indoor antenna capable of simultaneously covering both the N77 / N78 / N79 bands of 5G communication systems and the 5GHz band of the Wi-Fi 6 protocol is of great significance. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings and deficiencies of existing technologies and propose a simple and reliable broadband dual-polarized metasurface indoor access point antenna. Broadband excitation is achieved through a specially designed H-shaped feed slot and feed network. Simultaneously, a metasurface radiating structure with appropriate slots and non-uniform metasurface elements is used as the upper radiating structure to achieve broadband radiation. This antenna can operate stably in the 3.3GHz-5.9GHz frequency range, with a reflection coefficient of less than -10dB in the same range; and a gain of 8-12dBi in the passband.

[0008] To achieve the above objectives, the technical solution provided by this invention is as follows: a broadband dual-polarized metasurface indoor access point antenna, comprising a first dielectric substrate and a second dielectric substrate, wherein the first dielectric substrate is located above the second dielectric substrate and an air gap is left between them; a first copper-clad layer is provided on the upper surface of the first dielectric substrate, and a metasurface radiating structure is provided on the first copper-clad layer, wherein the metasurface radiating structure comprises uniform and non-uniform metasurface units, with gaps left between each pair of metasurface units, and energy is coupled through the gaps as equivalent capacitance; the uniform metasurface units are combined together and have X-shaped slots to expand the bandwidth; a second copper-clad layer and a third copper-clad layer are provided on the upper and lower surfaces of the second dielectric substrate, respectively; a plurality of H-shaped feed slots are provided on the second copper-clad layer, and the plurality of H-shaped feed slots are rotationally symmetrical about the center of the second copper-clad layer; a first feed network and a second feed network are provided on the third copper-clad layer, and the first feed network and the second feed network couple energy to the first copper-clad layer to radiate electromagnetic waves through the H-shaped feed slots.

[0009] Furthermore, the uniform metasurface units are combined together to form a cross-shaped structure, the X-shaped slit is located at the center of the cross-shaped structure, and the non-uniform metasurface units are distributed in the four quadrants of the cross-shaped structure.

[0010] Furthermore, the first power supply network is provided with a first power supply port, a first impedance input feed line, a first impedance transformation line and a first impedance output feed line connected in sequence.

[0011] Furthermore, the second power supply network is provided with a second power supply port, a second impedance input feed line, a second impedance transformation line, and a second impedance output feed line connected in sequence.

[0012] Furthermore, the first impedance input feed and the second impedance input feed are 50-ohm characteristic impedance input feeds.

[0013] Furthermore, the first impedance output feed and the second impedance output feed are 50-ohm characteristic impedance output feeds.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0015] This invention uses the input feed line coupled with an H-shaped feed slot as the feed structure to achieve broadband excitation. At the same time, it uses a metasurface radiation structure with appropriate slits and non-uniform metasurface units as the upper radiation structure to achieve broadband radiation, giving the antenna broadband operating characteristics. Its structure is simple, low profile, and high integration, and it has good application prospects. Attached Figure Description

[0016] Figure 1 This is an exploded view of the antenna of the present invention.

[0017] Figure 2 This is a cross-sectional view of the antenna of the present invention.

[0018] Figure 3 This is a schematic diagram of the structure of the first copper cladding layer.

[0019] Figure 4 This is a schematic diagram of the second copper cladding layer.

[0020] Figure 5 This is a schematic diagram of the third copper cladding layer.

[0021] Figure 6 The figure shows the simulation results of the S-parameters of the antenna of this invention.

[0022] Figure 7 The figure shows the simulation results of the gain and envelope correlation coefficient (ECC) curves of the antenna of the present invention.

[0023] Figure 8 This is a simulated radiation pattern of the center frequency of the antenna of this invention. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0025] See Figures 1 to 5As shown, this embodiment discloses a broadband dual-polarized metasurface indoor access point antenna, including a first dielectric substrate 2 and a second dielectric substrate 4. The first dielectric substrate 2 is located above the second dielectric substrate 4, with an air gap 6 between them. A first copper-clad layer 1 is provided on the upper surface of the first dielectric substrate 2, and a metasurface radiating structure is provided on the first copper-clad layer 1. The metasurface radiating structure includes uniform and non-uniform metasurface units 11 and 13, with gaps between each pair of metasurface units, and the energy is coupled through the gaps as equivalent capacitance. The surface units 11 are assembled together and have X-shaped slots 12 to expand the bandwidth; the upper and lower surfaces of the second dielectric substrate 4 are respectively provided with a second copper clad layer 3 and a third copper clad layer 5; the second copper clad layer 3 is provided with four H-shaped feeding slots 31, which are rotationally symmetrical about the center of the second copper clad layer 3; the third copper clad layer 5 is provided with a first feeding network 51 and a second feeding network 52, which couple energy to the first copper clad layer 1 through the H-shaped feeding slots 31 to radiate electromagnetic waves.

[0026] Specifically, the uniform metasurface units 11 are combined to form a cross-shaped structure, the X-shaped slits 12 are located at the center of the cross-shaped structure, and the non-uniform metasurface units 13 are distributed in the four quadrants of the cross-shaped structure.

[0027] Specifically, the first power supply network 51 is provided with a first power supply port 511, a first impedance input feed line 512, a first impedance transformation line 513 and a first impedance output feed line 514 connected in sequence; the second power supply network 52 is provided with a second power supply port 521, a second impedance input feed line 522, a second impedance transformation line 523 and a second impedance output feed line 524 connected in sequence.

[0028] Specifically, the first impedance input feed line 512 and the second impedance input feed line 522 are 50-ohm characteristic impedance input feed lines, and the first impedance output feed line 514 and the second impedance output feed line 524 are 50-ohm characteristic impedance output feed lines.

[0029] Specifically, the first dielectric substrate 2 and the second dielectric substrate 4 have a thickness of 0.508 mm, a length of 80 mm, a width of 80 mm, a dielectric constant of 2.55, and a loss tangent of 0.0029.

[0030] See Figure 6 The figure shows the S-parameter simulation results of the broadband dual-polarized metasurface indoor access point antenna described in this embodiment. As can be seen from the figure, the antenna of this invention has a reflection coefficient less than -10dB in the frequency range of 3.3GHz-5.9GHz, an inter-port isolation greater than 30dB, and a relative bandwidth exceeding 56.5%.

[0031] See Figure 7 The figure shows the gain curve and envelope correlation coefficient (ECC) simulation results of the broadband dual-polarized metasurface indoor access point antenna described in this embodiment. As can be seen from the figure, the antenna gain of this invention is flat and stable in the frequency range of 3.3 GHz to 5.9 GHz, with a gain of 8-12 dBi and an ECC of less than 0.001, exhibiting high gain and low correlation coefficient.

[0032] See Figure 8 The figure shows the simulation results of the center frequency direction of the broadband dual-polarized metasurface indoor access point antenna described in this embodiment. As can be seen from the figure, the antenna of this invention exhibits unidirectional radiation at the center frequency, and the cross-polarization level of the two principal planes is better than -28.5dB, demonstrating a low cross-polarization level.

[0033] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A broadband dual-polarized metasurface indoor access point antenna, characterized in that: The system includes a first dielectric substrate (2) and a second dielectric substrate (4), with the first dielectric substrate (2) located above the second dielectric substrate (4) and an air gap (6) between them. The upper surface of the first dielectric substrate (2) is provided with a first copper cladding layer (1), and a metasurface radiation structure is provided on the first copper cladding layer (1). The metasurface radiation structure includes uniform and non-uniform metasurface units, with gaps between each pair of metasurface units, and energy is coupled through the gaps as equivalent capacitance. The uniform metasurface units (11) are combined together and have X-shaped slits (12). To expand the bandwidth; the upper and lower surfaces of the second dielectric substrate (4) are respectively provided with a second copper clad layer (3) and a third copper clad layer (5); the second copper clad layer (3) is provided with a plurality of H-shaped feeding slots (31), which are rotationally symmetrical about the center of the second copper clad layer (3); the third copper clad layer (5) is provided with a first feeding network (51) and a second feeding network (52), which couple energy to the first copper clad layer (1) through the H-shaped feeding slots (31) to radiate electromagnetic waves.

2. The broadband dual-polarized metasurface indoor access point antenna according to claim 1, characterized in that: The uniform metasurface units (11) are combined to form a cross-shaped structure, the ×-shaped slit (12) is opened at the center of the cross-shaped structure, and the non-uniform metasurface units are distributed in the four quadrants of the cross-shaped structure.

3. The broadband dual-polarized metasurface indoor access point antenna according to claim 2, characterized in that: The first power supply network (51) is provided with a first power supply port (511), a first impedance input feed line (512), a first impedance transformation line (513) and a first impedance output feed line (514) connected in sequence.

4. The broadband dual-polarized metasurface indoor access point antenna according to claim 3, characterized in that: The second power supply network (52) is provided with a second power supply port (521), a second impedance input feed line (522), a second impedance transformation line (523), and a second impedance output feed line (524) connected in sequence.

5. A broadband dual-polarized metasurface indoor access point antenna according to claim 4, characterized in that: The first impedance input feed (512) and the second impedance input feed (522) are 50-ohm characteristic impedance input feeds.

6. A broadband dual-polarized metasurface indoor access point antenna according to claim 5, characterized in that: The first impedance output feed (514) and the second impedance output feed (524) are 50-ohm characteristic impedance output feeds.

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