A C-band broadband antenna based on double-layer metasurface

Abstract

This invention discloses a C-band broadband antenna based on a double-layer metasurface, belonging to the field of microwave communication technology. The antenna comprises, from top to bottom, an upper layer, a middle layer, and a lower layer dielectric substrate. The upper dielectric substrate has a first metasurface layer on its upper surface, the middle dielectric substrate has a second metasurface layer on its upper surface, and the lower dielectric substrate has a metal plate with a stripe groove on its upper surface and a tuning fork-type T-shaped power divider on its lower surface. The T-shaped power divider includes one main stub and two parallel branch stubs, with the branch stubs located directly below the stripe groove, which is perpendicular to the branch stubs. This invention achieves excellent performance in the 4.568 to 6.141 GHz frequency band by coupling the power divider with the stripe groove to excite multiple resonant modes, combined with the synergistic control of the double-layer metasurface of different sizes. This results in an S11 < -10 dB, a bandwidth of 34%, and a maximum gain of 8.25 dBi, making it suitable for 5G communication, satellite communication, and IoT devices.

Description

Technical Field

[0001] This invention relates to the field of microwave communication technology, specifically to a C-band broadband antenna based on a double-layer metasurface, which is particularly suitable for wireless communication systems in the 4.5-6.2 GHz frequency band and can be widely used in 5G communication, satellite communication and Internet of Things devices. Background Technology

[0002] With the rapid development of 5G communication technology and the popularization of IoT applications, the demand for broadband antennas is increasing. Among existing technologies, microstrip antennas are widely used in wireless communication systems due to their advantages such as simple structure, low cost, and easy integration. However, traditional microstrip antennas have limited bandwidth, usually only 5%-15%, which is difficult to meet the needs of modern communication systems for multi-band and broadband communication.

[0003] Metasurface technology, as a novel electromagnetic control method, has been applied in antenna design. However, in existing metasurface antenna designs, the synergistic optimization between the feed network and the metasurface is insufficient, resulting in suboptimal overall performance. T-type power dividers, as common feed networks, are frequently used in multi-port antenna systems, but research on their synergistic design with metasurface structures is limited. In existing technologies, the combination of T-type power dividers and metasurfaces often leads to structural redundancy, failing to achieve an optimal balance between bandwidth and gain. Furthermore, the application of double-layer metasurface structures in antenna design lacks systematic optimization methods, making it difficult to simultaneously meet the requirements of wide bandwidth, high gain, and compact structure.

[0004] Therefore, there is an urgent need for a new antenna design that can achieve wideband, high-gain antenna performance while maintaining a simple structure and ease of manufacturing, so as to meet the practical application requirements of modern wireless communication systems. Summary of the Invention

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

[0006] This invention is achieved through the following technical solution:

[0007] A C-band broadband antenna based on a double-layer metasurface includes three dielectric substrates stacked sequentially from top to bottom; wherein the upper surface of the upper dielectric substrate is provided with a first metasurface layer, the upper surface of the middle dielectric substrate is provided with a second metasurface layer, and the upper surface of the lower dielectric substrate is provided with a metal plate with a strip groove, and the lower surface is provided with a T-type power divider.

[0008] The T-type power divider has a tuning fork structure, including a main branch and two branch branches arranged in parallel; both branch branches are located directly below the strip groove, and the main branch is connected to the same side end of the two branch branches and extends outward.

[0009] Both the first metasurface layer and the second metasurface layer are 6×6 square patch arrays; wherein the side length of the square patch of the first metasurface layer is greater than the side length of the square patch of the second metasurface layer.

[0010] Furthermore, the dielectric constant of both the upper and lower dielectric substrates is 2.2, and the loss tangent is 0.0007. The thickness of the upper dielectric substrate is 1.2 mm, and the thickness of the lower dielectric substrate is 4 mm. The dielectric constant of the middle dielectric substrate is 2.5, the loss tangent is 0.0007, and the thickness is 0.1 mm.

[0011] Furthermore, the strip groove is perpendicular to the branching spur below it.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1. By using a synergistic design of a T-type power divider and a double-layer metasurface, broadband coverage of the 4.568GHz-6.141GHz frequency band was achieved, with a bandwidth of 34%, which is significantly better than existing technologies.

[0014] 2. By introducing the strip grooves on the metal plate, the radiation bandwidth of the antenna is effectively expanded, while the radiation efficiency is improved.

[0015] 3. The dual-layer metasurface structure optimizes the antenna's radiation characteristics through the synergistic effect of the first and second layers, achieving a maximum gain of 8.25 dB.

[0016] 4. The three-layer dielectric substrate structure ensures both antenna performance and structural compactness, making it easy to integrate into various wireless communication devices. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a T-type power divider according to an embodiment of the present invention.

[0018] Figure 2 This is a structural diagram of a strip groove on a metal plate according to an embodiment of the present invention.

[0019] Figure 3 This is a structural diagram of the first metasurface layer according to an embodiment of the present invention.

[0020] Figure 4 This is a structural diagram of the second metasurface layer according to an embodiment of the present invention.

[0021] Figure 5 This is a side view of the antenna.

[0022] Figure 6 This is the impedance matching S11 curve of the antenna.

[0023] Figure 7 This is the gain diagram of the antenna.

[0024] In the figure: 1. T-shaped power divider, 2. strip groove, 3. first metasurface layer, 4. second metasurface layer, 5. upper dielectric substrate, 6. middle dielectric substrate, 7. lower dielectric substrate. Detailed Implementation

[0025] The following is in conjunction with the appendix Figure 1-7 The embodiments and examples will further illustrate specific implementations of the present invention in detail.

[0026] This embodiment provides a C-band broadband antenna based on a double-layer metasurface. For example... Figures 1 to 5 As shown, the antenna adopts a multi-layer stacked structure, which includes, from top to bottom, an upper dielectric substrate 5, a middle dielectric substrate 6, and a lower dielectric substrate 7.

[0027] 1. Overall Implementation Principle

[0028] The core working principle of this antenna is to excite and modulate multiple resonant modes through a multi-layered structure, ultimately achieving broadband, high-gain radiation characteristics. Specifically: the T-shaped power divider 1 at the bottom layer is responsible for efficient feeding and exciting the initial radiation of the slot 2; the double-layer metasurface at the top, as the main radiator and beam modulator, is coupled and excited by the bottom layer structure and can also generate independent resonances; these multiple resonant modes generated by the slot and the double-layer metasurface superimpose and merge with each other in the frequency band, thereby significantly expanding the antenna's operating bandwidth. At the same time, the double-layer metasurface structure acts like an electromagnetic lens, effectively concentrating electromagnetic wave energy and significantly improving the antenna gain.

[0029] 2. Functions and descriptions of each layer of the structure

[0030] 2.1 Feeding Network Layer: T-type Power Divider 1

[0031] Structure and Location: This power divider adopts a tuning fork structure and is fabricated on the lower surface of the lower dielectric substrate 7. Its specific components include: a main branch 1-1 and two parallel branch branches 1-2.

[0032] Function: Its main function is to achieve equal amplitude and in-phase signal distribution. The signal enters from the input terminal of the main branch 1-1 and is evenly distributed to the two branch branches 1-2, ensuring that energy is uniformly fed to both sides of the upper radiating structure. This is the basis for forming a symmetrical radiation field and good impedance matching. The design also achieves a characteristic impedance matching of 50Ω, effectively reducing signal reflection.

[0033] 2.2 Coupled Radiation Layer: Grooved Metal Plate

[0034] Structure and Position: A metal plate is provided on the upper surface of the lower dielectric substrate 7, on which a strip groove 2 is etched. The orientation of the strip groove 2 is designed to be perpendicular to the branch nodes 1-2 directly below it.

[0035] Function: The core function of slot 2 is to achieve electromagnetic coupling and mode excitation. The current on stubs 1-2 is coupled to slot 2 through the electromagnetic field, exciting it to generate a slot resonant mode. This resonance is one of the fundamental frequencies for antenna operation. At the same time, slot 2 disturbs the normal current distribution on the metal plate, introducing additional resonant modes, which, combined with the resonance of the metasurface, broaden the antenna bandwidth.

[0036] 2.3 Core Radiation and Control Layer: Bilayer Metasurface

[0037] Structure and location:

[0038] The second metasurface layer 4 is located on the upper surface of the intermediate dielectric substrate 6.

[0039] The first metasurface layer 3 is located on the upper surface of the upper dielectric substrate 5.

[0040] Both metasurfaces use a 6×6 square patch array, and the side length of the square patch in the first metasurface layer 3 is greater than the side length of the square patch in the second metasurface layer 4.

[0041] Function: The dual-layer metasurface structure with different sizes is the key to the high performance of this antenna.

[0042] Multiple resonances are generated: Due to the different patch sizes, the first and second metasurface layers will generate different but adjacent resonant frequencies, and their superposition directly contributes to the broadband characteristics.

[0043] Co-controlled beamforming: These two metasurface layers, together with the slot below, form a complex resonant cavity and partial reflective surface (PRS) structure. Electromagnetic waves are reflected and interfered with multiple times between them, ultimately being effectively guided and radiated. This synergistic effect optimizes the antenna's radiation direction and, like a lens, focuses electromagnetic wave energy, thereby significantly improving the antenna gain.

[0044] 2.4 Support and isolation layers: dielectric substrate

[0045] Structure and parameters:

[0046] Upper dielectric substrate 5: thickness 1.2mm, dielectric constant 2.2, loss tangent 0.0007.

[0047] Intermediate dielectric substrate 6: thickness 0.1mm, dielectric constant 2.5, loss tangent 0.0007.

[0048] Lower dielectric substrate 7: 4mm thickness, dielectric constant 2.2, loss tangent 0.0007.

[0049] Function: The three dielectric substrates constitute the mechanical body of the antenna. They not only provide support for the metal structures of each layer, but their specific thickness and dielectric constant distribution are also part of the antenna performance optimization. In particular, the extremely thin middle dielectric substrate 6 ensures strong electromagnetic coupling between the first metasurface layer 3 and the second metasurface layer 4, which is crucial for stimulating synergistic effects. The extremely low loss tangent of all substrates ensures low loss in high-frequency signal transmission.

[0050] 3. Performance and Effects

[0051] In this embodiment, the key dimensions of the antenna structure are as follows (unit: millimeters):

[0052] a = 20; b = 20; c = 4; d = 16; e = 6; f = 5.

[0053] like Figure 6 As shown, the return loss S11 of this antenna is less than -10dB in the frequency band from 4.568GHz to 6.141GHz, and the relative bandwidth reaches 34%, proving that the above-mentioned multi-resonance principle has successfully achieved excellent broadband impedance matching characteristics.

[0054] like Figure 7 As shown, the antenna achieves a maximum gain of 8.25 dB near the 5 GHz band, verifying the excellent effect of the double-layer metasurface structure in improving radiation efficiency and controlling beam.

[0055] In summary, this invention successfully constructs a high-performance C-band broadband antenna through a synergistic design of "uniform feeding with a tuning fork-type T-shaped power divider + introducing multiple resonances with a strip slot + expanding bandwidth and improving gain with a double-layer metasurface of different sizes".

Claims

1. A C-band broadband antenna based on a double-layer metasurface, characterized in that, It includes three dielectric substrates stacked from top to bottom; wherein the upper dielectric substrate (5) has a first metasurface layer (3) on its upper surface and the middle dielectric substrate (6) has a second metasurface layer (4) on its upper surface; the lower dielectric substrate (7) has a metal plate with a strip groove (2) on its upper surface and a T-shaped power divider (1) on its lower surface. The T-type power divider (1) is a tuning fork structure, including a main branch (1-1) and two branch branches (1-2) arranged in parallel; both branch branches (1-2) are located directly below the strip 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 greater than the side length of the square patch of the second metasurface layer (4); The dielectric constant of the upper dielectric substrate (5) and the lower dielectric substrate (7) are both 2.2, and the loss tangent is both 0.0007. The thickness of the upper dielectric substrate (5) is 1.2 mm, and the thickness of the lower dielectric substrate (7) is 4 mm. The dielectric constant of the middle dielectric substrate (6) is 2.5, the loss tangent is 0.0007, and the thickness is 0.1 mm. The strip groove (2) is perpendicular to the branching nodes (1-2) below it.

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