Artificial surface plasmon polariton antenna structure
By loading parasitic SSPP TL at the end of the main SSPP TL of the antenna and using the periodic slot structure to excite different frequency bands, the gain optimization problem of traditional antennas in large frequency ratio dual-band design is solved, and the gain improvement in millimeter wave and Sub-6GHz bands is achieved.
Patent Information
- Application Number
- CN202510261735.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-06
- Publication Date
- 2025-05-16
AI Technical Summary
In the design of high frequency ratio dual-band antennas, it is difficult to optimize the gain performance of both frequency bands simultaneously, especially in the design of millimeter wave and Sub-6GHz bands.
Using an artificial surface plasmon antenna structure, by loading parasitic SSPP TL at the end of the main SSPP TL, different modes are excited using the periodically distributed groove structure, thereby achieving gain enhancement in different frequency bands.
A significant increase in gain in the millimeter wave and Sub-6GHz bands is achieved, with an average gain of 4dB and 1.6dB, and a high degree of integration and compactness of the antenna structure is maintained.
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Figure CN120016147A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of antennas, and in particular to an artificial surface plasmon antenna structure. Background Art
[0002] With the rapid development of modern communication technology, especially the widespread application of 5G technology, the requirements for antenna performance are increasing. High-gain antennas have become a key technology to meet the needs of high-speed data transmission, low latency and high reliability. However, traditional antennas have limitations in gain enhancement, especially in the design of large frequency ratio dual-band antennas, it is difficult to optimize the gain performance of two frequency bands at the same time.
[0003] In order to improve the antenna gain, the existing technology has adopted a variety of methods. For example, the omnidirectional radiation gain in the Sub-6GHz band is improved by forming an array structure through multiple identical or similar antenna elements. However, this method usually requires a complex feeding network, which increases the difficulty of design and implementation. Another method is to load an artificial surface plasmon structure on the basis of the traditional antenna structure to improve the gain of the directional antenna in the millimeter wave band. However, most of these methods are only aimed at improving the gain of single-band antennas, and the design of dual-band antennas with large frequency ratios still faces challenges. Summary of the invention
[0004] The purpose of the present application is to overcome the defects in the above-mentioned prior art and provide an artificial surface plasmon antenna structure.
[0005] The present application provides an artificial surface plasmon antenna structure, comprising: a single-layer substrate, a metal ground, a main artificial surface plasmon transmission line and a parasitic artificial surface plasmon transmission line;
[0006] The metal ground is arranged at the bottom of the single-layer substrate;
[0007] The main artificial surface plasmon transmission line is arranged on the top of the single-layer substrate, and the parasitic artificial surface plasmon transmission line is loaded on the end of the main artificial surface plasmon transmission line;
[0008] The main artificial surface plasmon transmission line and the parasitic artificial surface plasmon transmission line use periodically distributed slot structures as units.
[0009] Optionally, the unit of the main artificial surface plasmon transmission line realizes a double-sided inclined groove structure by rotating the non-inclined unit 45 degrees counterclockwise.
[0010] Optionally, the parasitic artificial surface plasmon transmission line excites an odd mode in a millimeter wave frequency band.
[0011] Optionally, the parasitic artificial surface plasmon transmission line excites an even mode through coupling in the Sub-6 GHz frequency band.
[0012] Optionally, the main artificial surface plasmon transmission line and the metal ground are both made of metal-plated copper.
[0013] Optionally, the parasitic artificial surface plasmon transmission line controls the phase of the unit in the millimeter wave frequency band by adjusting the geometric parameters of the unit, thereby controlling the propagation of the electromagnetic surface wave.
[0014] Optionally, through the parasitic artificial surface plasmon transmission, a new monopole mode introduced in the Sub-6 GHz frequency band generates a new resonance point.
[0015] Optionally, the artificial surface plasmon antenna structure does not include a feeding network.
[0016] Optionally, the main artificial surface plasmon transmission line is divided into four regions, region I consists of a microstrip transmission line, region II includes a group of rectangular grooves, region III includes a group of rectangular grooves with a constant groove depth, and region IV includes rectangular grooves with a decreasing groove depth gradient.
[0017] The beneficial effects of this application are:
[0018] The present application provides an artificial surface plasmon antenna structure, comprising: a single-layer substrate, a metal ground, a main artificial surface plasmon transmission line and a parasitic artificial surface plasmon transmission line; the metal ground is arranged at the bottom of the single-layer substrate; the main artificial surface plasmon transmission line is arranged on the top of the single-layer substrate, and the parasitic artificial surface plasmon transmission line is loaded at the end of the main artificial surface plasmon transmission line; the main artificial surface plasmon transmission line and the parasitic artificial surface plasmon transmission line use a periodically distributed slot structure as a unit. The main artificial surface plasmon transmission line and the parasitic artificial surface plasmon transmission line in the present application use a periodically distributed slot structure as a unit. This structure can excite different modes, thereby achieving gain enhancement. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a schematic diagram of the structure of an artificial surface plasmon antenna in this application;
[0020] Figure 2 It is a schematic diagram of the dual-band antenna structure in this application;
[0021] Figure 3 is an H-plane schematic diagram of the surface current and radiation pattern on the SSPP TL at 25.5 GHz in this application;
[0022] Figure 4 is an H-plane schematic diagram of the surface current and radiation pattern on the SSPP TL at 2.5 GHz in this application;
[0023] Figure 5 is a schematic diagram of the surface current and surface electric field on the parasitic SSPP TL at 25.5 GHz in this application;
[0024] Figure 6 is the gain and S of the parasitic and non-parasitic SSPP TL antennas of different lengths in this application 11 Schematic diagram;
[0025] Figure 7 is a schematic diagram of the current distribution on the parasitic SSPP TL surface electric field distribution at 2.5 GHz in this application;
[0026] Figure 8 This application is SSPP TL in different L m S under and without parasitic SSPP TL 11 Schematic diagram;
[0027] Fig. 9 is the parasitic SSPP TL in this application at different L m Schematic diagram of TL gain with and without parasitic SSPP;
[0028] Fig.10 is a schematic diagram of the antenna prototype in this application;
[0029] Fig.11 It is the S of the antenna Sub-6GHz band in this application 11 and gain diagram;
[0030] Fig.12 It is a schematic diagram of the radiation pattern of the antenna in the Sub-6GHz frequency band in this application;
[0031] Fig.13 is the S of the millimeter wave frequency band of the antenna in this application 11 and gain diagram;
[0032] Fig.14 It is a schematic diagram of the radiation pattern of the antenna in the millimeter wave frequency band in this application. DETAILED DESCRIPTION
[0033] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that various forms of implementing the present disclosure should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.
[0034] Please refer to Figure 1 As shown, the present application provides an artificial surface plasmon antenna structure.
[0035] The overall design idea is to load a parasitic SSPP TL at the end of an SSPP TL antenna with a large frequency ratio and dual-band characteristics, and use the parasitic structure to excite different modes in different frequency bands to achieve gain enhancement. Specifically, in the millimeter wave band, the parasitic SSPP TL excites the odd mode and acts as a gradient refractive index lens to enhance the antenna gain; in the Sub-6GHz band, the parasitic SSPP TL excites the even mode through coupling, forming a 1×2 array with the tilted SSPP TL to improve the omnidirectional radiation gain. This technical solution not only improves the gain performance of the antenna, but also introduces a monopole mode to generate a resonance point to optimize the impedance bandwidth and maintain the high integration and compactness of the antenna structure.
[0036] Antenna structure configuration:
[0037] The antenna is built on a single-layer RT / Duroid5880 substrate with a relative dielectric constant of 2.2 and a substrate thickness of t=0.508 mm. Figure 1 As shown on the left side of the figure, the bottom of the antenna is a metal ground with a length of W = 50 mm and a width of L = 12 mm. The main SSPP TL on the top uses a periodically distributed double-sided tilted slot structure as its unit. The tilted unit is realized by rotating the non-tilted unit 45 degrees counterclockwise, as shown in Figure 1 Shown enlarged on the right.
[0038] like Figure 2 As shown in the top view of the antenna, the antenna is divided into four different regions: Region I consists of a microstrip TL with a width of 1.5mm; Region II has a set of rectangular grooves etched on the right, as shown in the enlarged view; Region III maintains a constant groove depth; Region IV has a gradient reduction in the groove depth. The top main SSPP TL and the bottom ground are both 0.035mm thick metal-plated copper.
[0039] A parasitic SSPP TL is loaded at the end of the main SSPP TL. The parasitic SSPP TL is a straight slot, and the rest of the structure remains the same as the preliminary dual-band antenna design. The periodicity of the parasitic SSPP unit is p2 = 1mm, the slot width is a3, and the depth h3 is 0.5mm and 0.9mm respectively. The width W of the parasitic SSPP TL is p =2.7mm, length is L m =44mm distance from main SSPP TL is L p =4mm.
[0040] like Figure 1 As shown, L1 = 8, L2 = 4, L3 = 21, L4 = 6, W S =4, a=0.6, p=1, h=0.8, p1=0.72, a1=0.32, W m =0.508, units are mm.
[0041] like Figure 2 As shown, L p =4, L m =44, L=100, W=50, W p =2.7, all units are mm.
[0042] Working principle:
[0043] A set of rectangular slots is introduced on the right side of region II. This design creates a half-wavelength path length difference between the two sides of the main SSPP TL in mm-wave, resulting in a 180-degree phase shift. This phase shifter effectively converts the even mode of the main SSPP TL to the odd mode in the mm-wave band.
[0044] like Figure 3 The current distribution on the SSPP TL in odd mode, shown on the left, shows that the current vectors flow into and out of both sides of the symmetrical SSPP cell.
[0045] like Figure 3 As shown on the right, this allows the odd-mode SSPP TL to act as an array of small current sources, producing end-launched radiation along the y-axis in the far field.
[0046] like Figure 4 As shown on the left, in the Sub-6 GHz band, the path length of the phase shifter is much shorter than the operating wavelength, which makes its effect on the phase of the transmission line negligible. Therefore, it does not change the even-mode characteristics of the main SSPP TL.
[0047] like Figure 4 As shown on the right, the symmetrical SSPP TL generates current vectors with opposite phases on both sides, forming standing waves along its finite length. This results in omnidirectional radiation.
[0048] Gain enhancement principle:
[0049] Millimeter wave band: The parasitic SSPP structure controls the propagation of electromagnetic surface waves by adjusting the geometric parameters of the unit to control its phase. The wave propagation along the SSPP TL is slower than light, resulting in a higher effective refractive index than air. This creates a lateral gradient in front of the antenna, acting as a gradient refractive index lens, thereby significantly improving the gain.
[0050] like Figure 5As shown on the left, the odd-mode surface current distribution on the antenna parasitic SSPP TL, and the current direction is distributed in the same direction on both sides.
[0051] like Figure 5 The right side shows the surface electric field distribution at 25.5 GHz, where the SSPP TL concentrates the electric field and acts as an equivalent lens, significantly improving the antenna gain.
[0052] like Figure 6 As shown in the figure, the different parasitic SSPP TL lengths (L m ) and the antenna gain when there is no L m As the gain of the antenna increases, the gain of the antenna will also increase. m =44, the gain enhancement effect weakens, considering that the antenna's Sub-6GHz band gain begins to decrease (such as Fig. 9 Therefore, select L m =44 is the optimal choice. The results show that the average gain across the entire operating bandwidth is improved by 4dB compared to the preliminary antenna. Importantly, the addition of the parasitic SSPP TL does not affect the antenna's operating frequency band.
[0053] Microwave band: In the Sub-6 GHz band, the main SSPP TL excites the parasitic SSPP TL through coupling to generate even modes.
[0054] like Figure 5 As shown on the left, the even-mode surface current distribution on the antenna parasitic SSPP TL, with the current direction opposite on both sides.
[0055] like Figure 7 The right side shows the surface electric field distribution of the antenna after adding the parasitic SSPP TL, indicating that both the main SSPP TL and the parasitic SSPP TL are excited. The addition of the parasitic SSPP TL introduces a monopole mode to generate a resonance point, significantly broadening the impedance bandwidth.
[0056] like Figure 8 As shown in Figure 1, without the parasitic SSPP TL, the antenna has only one resonance point (f1). However, adding the parasitic SSPP TL introduces a second resonance point (f2). m As L increases, f2 shifts to a lower frequency. m At 44mm, the impedance bandwidth of the antenna increases by 100%.
[0057] In addition, the main SSPP TL and the parasitic SSPP TL form a 1 × 2 array, eliminating the need for a complex feeding structure through coupled feeding.
[0058] like Fig. 9 As shown in Figure 1, without the parasitic SSPP TL, the antenna gain fluctuates between 0.89 and 1.85 dBi. Adding the parasitic SSPP TL significantly affects the gain. m As L increases, the peak gain initially rises and then decreases. m =44mm, the antenna gain ranges from 1.96 to 3.69dBi. Compared with the antenna without adding parasitic SSPP TL, the average gain of the proposed antenna is improved by about 1.6dB.
[0059] In order to evaluate the performance of the antenna, a prototype was fabricated and tested.
[0060] Fig.10 Two schematic diagrams of the prototype are depicted. The S 11 The parameters were measured using a network analyzer and the far-field performance was measured in a microwave anechoic chamber and the results of the antenna were compared with those of a simulated antenna.
[0061] like Fig.11 As shown in the figure, the measured and simulated S 11 The measured results are in good agreement with the simulated results. The antenna achieves the measured impedance bandwidth (S 11 <-10dB) is 21.4% (2.21–2.74GHz), including 5G bands n7, n30, n34, n40, n41, n53, and n90. The measured gain and simulated gain of the Sub-6GHz band are 1.69-3.69dBi and 1.96-3.69dBi, respectively.
[0062] like Fig.12 The following are the normalized radiation patterns measured and simulated in the E-plane and H-plane at 2.4 GHz and 2.6 GHz. The antenna exhibits good omnidirectional radiation characteristics. In addition, the cross-polarization level is lower than -17 dB in both planes.
[0063] like Fig.13 As shown in the figure, the measured and simulated S 11 The measured results show that the impedance bandwidth is 24.9% (22.2-28.5GHz), and the simulation results show 23.6% (22.1-28GHz), both covering the 5G FR2 n258 band and most of the n257 band. The figure also shows that the measured and simulated peak gains of the antenna are 13.2dBi and 13.4dBi respectively.
[0064] like Fig.14Figure 2 shows the measured and simulated radiation patterns at 24 GHz and 26 GHz. All measured radiation patterns show stability in the main radiation direction and are in good agreement with the simulation predictions.
Claims
1. An artificial surface plasmon antenna structure, characterized in that: include: A single-layer substrate, a metal ground, a main artificial surface plasmon transmission line and a parasitic artificial surface plasmon transmission line; The metal ground is arranged at the bottom of the single-layer substrate; The main artificial surface plasmon transmission line is arranged on the top of the single-layer substrate, and the parasitic artificial surface plasmon transmission line is loaded on the end of the main artificial surface plasmon transmission line; The main artificial surface plasmon transmission line and the parasitic artificial surface plasmon transmission line use periodically distributed slot structures as units.
2. The artificial surface plasmon antenna structure according to claim 1, characterized in that: The unit of the main artificial surface plasmon transmission line realizes a double-sided inclined groove structure by rotating the non-inclined unit 45 degrees counterclockwise.
3. The artificial surface plasmon antenna structure according to claim 1, characterized in that: The parasitic artificial surface plasmon transmission line excites odd modes in the millimeter wave frequency band.
4. The artificial surface plasmon antenna structure according to claim 1, characterized in that: The parasitic artificial surface plasmon transmission line excites an even mode through coupling in the Sub-6 GHz frequency band.
5. The artificial surface plasmon antenna structure according to claim 1, characterized in that: The main artificial surface plasmon transmission line and the metal ground are both made of metal-plated copper.
6. The artificial surface plasmon antenna structure according to claim 1, characterized in that: The parasitic artificial surface plasmon transmission line controls the phase of the unit by adjusting the geometric parameters of the unit in the millimeter wave frequency band, thereby controlling the propagation of the electromagnetic surface wave.
7. The artificial surface plasmon antenna structure according to claim 4, characterized in that: Through the parasitic artificial surface plasmon transmission, new monopole modes and resonance points are introduced in the Sub-6GHz band.
8. The artificial surface plasmon antenna structure according to claim 1, characterized in that: The artificial surface plasmon antenna structure does not include a feeding network.
9. The artificial surface plasmon antenna structure according to claim 1, characterized in that: The main artificial surface plasmon transmission line is divided into four regions, region I consists of a microstrip transmission line, region II includes a group of rectangular grooves, region III includes a group of rectangular grooves with a constant groove depth, and region IV includes rectangular grooves with a decreasing groove depth gradient.