C-band broadband antenna based on double-layer metasurface

Abstract

The invention discloses a C-band broadband antenna based on a double-layer metasurface, and belongs to the technical field of microwave communication. The antenna comprises an upper-layer dielectric substrate, a middle-layer dielectric substrate and a lower-layer dielectric substrate from top to bottom, a first metasurface layer is arranged on the upper surface of the upper-layer dielectric substrate, a second metasurface layer is arranged on the upper surface of the middle-layer dielectric substrate, a metal plate with a strip-shaped groove is arranged on the upper surface of the lower-layer dielectric substrate, and a tuning fork type T-shaped power divider is arranged on the lower surface of the lower-layer dielectric substrate. The T-shaped power divider comprises a main branch knot and two parallel branch knots, the branch knots are located under the strip-shaped groove, and the strip-shaped groove is perpendicular to the branch knots. Through a power divider and strip-shaped groove coupling excitation multi-resonance mode, in combination with cooperative regulation and control of the double-layer different-size metasurfaces, the excellent performance that S11 is smaller than-10 dB, the bandwidth is 34% and the maximum gain is 8.25 dBi is achieved within the frequency band of 4.568-6.141 GHz, and the ultra-wideband ultra-wideband antenna is suitable for 5G communication, satellite communication and Internet of Things equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microwave communication, in particular to a C-band broadband antenna based on double-layer metasurface, which is particularly suitable for wireless communication systems in the frequency band of 4.5-6.2GHz and can be widely applied in the fields of 5G communication, satellite communication and Internet of Things devices. BACKGROUND

[0002] With the rapid development of 5G communication technology and the popularity of Internet of Things applications, the demand for broadband antennas is increasing. In the prior art, microstrip antennas are widely used in wireless communication systems due to their simple structure, low cost and easy integration. However, the bandwidth of traditional microstrip antennas is limited, usually only 5%-15%, which cannot meet the demand of modern communication systems for multi-band and wideband communication.

[0003] As a new type of electromagnetic control method, metasurface technology has been applied in antenna design. However, in existing metasurface antenna design, the coordination optimization of the feed network and the metasurface is insufficient, resulting in suboptimal overall performance. T-type power divider, as a common feed network, is often used in multi-port antenna systems, but there is little research on the coordinated design of T-type power divider and metasurface structure. In the prior art, the combination of T-type power divider and metasurface often leads to structural redundancy, which cannot achieve the best balance between bandwidth and gain. In addition, the application of double-layer metasurface structure in antenna design lacks systematic optimization methods, making it difficult to meet the requirements of wideband, high gain and compact structure at the same time.

[0004] Therefore, there is an urgent need for a new antenna design to achieve wideband and high gain antenna performance while maintaining a simple structure and easy manufacturing to meet the practical application requirements of modern wireless communication systems. SUMMARY

[0005] To achieve the above-mentioned purpose, the present application proposes a C-band broadband antenna based on double-layer metasurface structure, which has a compact structure and can be integrated into various wireless communication devices.

[0006] The present application is realized by the following technical solutions: A C-band broadband antenna based on double-layer metasurface, comprising three layers of dielectric substrates stacked from top to bottom; wherein the upper surface of the upper layer of dielectric substrate is provided with a first metasurface layer, and the upper surface of the middle layer of dielectric substrate is provided with a second metasurface layer; the upper surface of the lower layer of dielectric substrate is provided with a metal plate with a strip-shaped slot, and the lower surface is provided with a T-type power divider; The T-type power divider is a tuning fork structure, comprising one main branch and two branch branches arranged in parallel; the two branch branches are located directly below the strip-shaped slot, and the main branch is connected to the same side of the two branch branches and extends outward; The first super surface layer and the second super surface layer are both square patch arrays of 6*6; wherein the side length of the square patch of the first super surface layer is greater than the side length of the square patch of the second super surface layer.

[0007] Further, the dielectric constant of the upper layer medium substrate and the lower layer medium substrate is 2.2, and the loss tangent is 0.0007, wherein the thickness of the upper layer medium substrate is 1.2mm, and the thickness of the lower layer medium substrate is 4mm; the dielectric constant of the middle layer medium substrate is 2.5, the loss tangent is 0.0007, and the thickness is 0.1mm.

[0008] Further, the strip-shaped groove is perpendicular to the shunt branch below it.

[0009] Compared with the background art, the present application has the following advantages: 1. Through the cooperative design of the T-shaped power divider and the double-layer super surface, wideband coverage of 4.568GHz-6.141GHz frequency band is realized, and the bandwidth reaches 34%, which is significantly better than the prior art.

[0010] 2. Through the introduction of the strip-shaped groove on the metal plate, the radiation bandwidth of the antenna is effectively expanded, and the radiation efficiency is improved.

[0011] 3. The double-layer super surface structure optimizes the radiation characteristics of the antenna through the cooperative action of the first layer and the second layer, so that the highest gain reaches 8.25dB.

[0012] 4. The three-layer medium substrate structure not only ensures the performance of the antenna, but also maintains the compactness of the structure, which is convenient for integration into various wireless communication devices. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a T-shaped power divider schematic diagram of the embodiment of the present application.

[0014] Figure 2 is a strip-shaped groove structure diagram on the metal plate of the embodiment of the present application.

[0015] Figure 3 is a first super surface layer structure diagram of the embodiment of the present application.

[0016] Figure 4 is a second super surface layer structure diagram of the embodiment of the present application.

[0017] Figure 5 is a side view of the antenna.

[0018] Figure 6 is an impedance matching S11 curve diagram of the antenna.

[0019] Figure 7 is a gain diagram of the antenna.

[0020] In the figure: 1, T-type power divider, 2, strip slot, 3, first metasurface layer, 4, second metasurface layer, 5, upper layer dielectric substrate, 6, middle layer dielectric substrate, 7, lower layer dielectric substrate. DETAILED DESCRIPTION

[0021] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings and examples. Figures 1-7

[0022] The present embodiment provides a C-band broadband antenna based on double-layer metasurface. As shown in the figure, the antenna adopts a multi-layer stacked structure, which includes, from top to bottom, an upper layer dielectric substrate 5, a middle layer dielectric substrate 6 and a lower layer dielectric substrate 7. Figures 1 to 5

[0023] 1. Overall implementation principle The core working principle of the antenna is to excite and control multiple resonance modes through a multi-layer structure, and finally realize the radiation characteristics of wideband and high gain. Specifically: the T-type power divider 1 located at the bottom is responsible for efficient feeding and exciting the initial radiation of the strip slot 2; the double-layer metasurface located at the top as the main radiator and beam controller is coupled and excited by the bottom structure, and can also produce independent resonance by itself; these multiple resonance modes produced by the slot and the double-layer metasurface are superimposed and fused on the frequency band, thereby significantly expanding the working bandwidth of the antenna. At the same time, the double-layer metasurface structure can effectively converge electromagnetic wave energy, significantly improving the antenna gain.

[0024] 2. Function and description of each layer structure 2.1 Feeding network layer: T-type power divider 1 Structure and position: The power divider adopts a tuning fork structure and is made on the lower surface of the lower layer dielectric substrate 7. Its specific composition includes: one main branch 1-1 and two parallelly arranged branch branches 1-2.

[0025] Function: Its main function is to realize the equal-amplitude and in-phase distribution of signals. The signal enters from the input end of the main branch 1-1 and is evenly distributed to the two branch branches 1-2, ensuring that the energy is uniformly fed to the two sides of the upper radiation structure, which is the basis for forming a symmetrical radiation field and good impedance matching. This design also realizes a characteristic impedance matching of 50Ω, effectively reducing signal reflection.

[0026] 2.2 Coupling radiation layer: slotted metal plate Structure and position: A metal plate is provided on the upper surface of the lower layer dielectric substrate 7, and a strip slot 2 is etched on the metal plate. The orientation of the strip slot 2 is designed to be perpendicular to the branch branch 1-2 directly below it.

[0027] ​​Function: The core function of this strip slot 2 is to realize electromagnetic coupling and mode excitation. The current on the shunt branch 1-2 is coupled to the strip slot 2 through electromagnetic field, exciting it to generate slot resonance mode. This resonance is one of the basic frequency points of the antenna operation. At the same time, the strip slot 2 disturbs the normal current distribution on the metal plate, introducing additional resonance modes, which, combined with the resonance of the metasurface, together expand the antenna bandwidth.

[0028] 2.3 Core radiation and regulation layer: double-layer metasurface Structure and position: The second metasurface layer 4 is located on the upper surface of the middle layer dielectric substrate 6.

[0029] The first metasurface layer 3 is located on the upper surface of the upper layer dielectric substrate 5.

[0030] Both layers of metasurfaces use 6x6 square patch arrays, and the square patch side length of the first metasurface layer 3 is larger than that of the second metasurface layer 4.

[0031] Function: The double-layer metasurface structure with different sizes is the key to realizing high performance of the antenna.

[0032] Multiple resonances: Due to the different patch sizes, the first and second layers of metasurfaces themselves will produce different but adjacent resonance frequencies, and their superposition directly contributes to the wideband characteristics.

[0033] Co-regulation beam: The two layers of metasurfaces together with the slot below form a complex resonant cavity and partially reflective surface (PRS) structure. Electromagnetic waves are reflected and interfered multiple times between them, and finally effectively directed and radiated out. This synergistic effect optimizes the antenna's radiation direction and converges electromagnetic wave energy like a lens, thereby significantly improving the antenna gain.

[0034] 2.4 Support and isolation layer: dielectric substrate Structure and parameters: Upper layer dielectric substrate 5: thickness 1.2mm, dielectric constant 2.2, loss tangent 0.0007.

[0035] Middle layer dielectric substrate 6: thickness 0.1mm, dielectric constant 2.5, loss tangent 0.0007.

[0036] Lower layer dielectric substrate 7: thickness 4mm, dielectric constant 2.2, loss tangent 0.0007.

[0037] Function: The three-layer dielectric substrate constitutes the mechanical body of the antenna. They not only provide support for the metal structures of each layer, but also their specific thickness and permittivity distribution are part of the antenna performance optimization. In particular, the extremely thin middle layer dielectric substrate 6 ensures strong electromagnetic coupling between the first metasurface layer 3 and the second metasurface layer 4, which is essential for exciting the synergistic effect. The extremely low loss tangent of all substrates ensures low loss of high-frequency signal transmission.

[0038] 3. Performance and effects In this embodiment, the key dimensions of the antenna structure are as follows (unit: millimeter): a = 20; b = 20; c = 4; d = 16; e = 6; f = 5.

[0039] As shown in Figure 6 , the return loss S11 of the antenna in the frequency band of 4.568GHz to 6.141GHz is less than -10dB, and the relative bandwidth reaches 34%, which proves that the above-mentioned multi-resonance principle successfully realizes excellent wideband impedance matching characteristics.

[0040] As shown in Figure 7 , the highest gain of the antenna near the 5GHz frequency band reaches 8.25dB, which verifies the excellent effect of the double-layer metasurface structure in improving the radiation efficiency and controlling the beam.

[0041] Summary: Through the synergistic design of "tuning fork type T-shaped power divider uniform feeding + bar slot multi-resonance + double-layer different size metasurface to expand bandwidth and improve gain", a high-performance C-band wideband antenna is successfully constructed.

Claims

1. A C-band broadband antenna based on double-layer metasurface, characterized in that, The application relates to a three-layer medium substrate which is stacked from top to bottom; wherein the upper surface of the upper layer medium substrate (5) is provided with a first metasurface layer (3), the upper surface of the middle layer medium substrate (6) is provided with a second metasurface layer (4), the upper surface of the lower layer medium substrate (7) is provided with a metal plate with a strip-shaped groove (2), and the lower surface is provided with a T-shaped power divider (1). The T-shaped power divider (1) is of a tuning fork type structure and comprises one main branch (1-1) and two branch branches (1-2) which are arranged in parallel; the two branch branches (1-2) are located directly below the strip-shaped groove (2), and the main branch (1-1) is connected to the same side end of the two branch branches (1-2) and extends outward. The first metasurface layer (3) and the second metasurface layer (4) are both 6*6 square patch arrays; wherein the side length of the square patch of the first metasurface layer (3) is larger than that of the second metasurface layer (4).

2. The dual-layer metasurface-based C-band broadband antenna according to claim 1, wherein, The dielectric constant of the upper layer medium substrate (5) and the lower layer medium substrate (7) is 2.2, and the loss tangent is 0.0007; wherein the thickness of the upper layer medium substrate (5) is 1.2 mm, and the thickness of the lower layer medium substrate (7) is 4 mm; the dielectric constant of the middle layer medium substrate (6) is 2.5, the loss tangent is 0.0007, and the thickness is 0.1 mm.

3. The dual-layer metasurface-based C-band broadband antenna according to claim 1, wherein, The strip-shaped groove (2) is perpendicular to the branch branch (1-2) below.

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