An externally perceivable smart leaky-wave antenna based on spoof surface plasmon polaritons

Smart antennas have received great attention for their potentials to enable communication and perception functions at the same time.However,realizing the function synthesis remains an open challenge,and most existing system solutions are limited to narrow operating bands and high complexity and cost.Here,we propose an externally perceivable leakywave antenna(LWA)based on spoof surface plasmon polaritons(SSPPs),which can realize adaptive real-time switching between the“radiating”and“non-radiating”states and beam tracking at different frequencies.With the assistance of computer vision,the smart SSPP-LWA is able to detect the external target user or jammer,and intelligently track the target by self-adjusting the operating frequency.The proposed scheme helps to reduce the power consumption through dynamically controlling the radiating state of the antenna,and improve spectrum utilization and avoid spectrum conflicts through intelligently deciding the radiating frequency.On the other hand,it is also helpful for the physical layer communication security through switching the antenna working state according to the presence of the target and target beam tracking in real time.In addition,the proposed smart antenna can be generalized to other metamaterial systems and could be a candidate for synaesthesia integration in future smart antenna systems.

Spoof surface plasmon polaritons excited leaky-wave antenna with continuous scanning range from endfire to forward

A novel leaky-wave antenna(LWA)utilizing spoof surface plasmon polaritons(SSPPs)excitation is proposed with continuous scanning range from endfire to forward.The designed transmission line unit supports two SSPPS modes,of which the 2nd order mode is applied in the design.A novel strategy has been devised to excite the spatial radiation of the-1st order harmonics by arranging periodic counter changed sinusoidal structures on both sides of the SSPPs transmission line.Both full-wave simulation and measurement results show that the proposed LWA presents wide scanning angle from endfire to forward.In the frequency range from 4 GHz to 10 GHz,LWAs achieve scanning from 90°to+20°,covering the entire backward quadrant continuously.

High-confinement ultra-wideband bandpass filter using compact folded slotline spoof surface plasmon polaritons

A novel bandpass filter(BPF)based on spoof surface plasmon polaritons(SSPPs)using a compact folded slotline structure is proposed and experimentally demonstrated.The proposed novel SSPPs structure compared with a conventional plasmonic waveguide with slot line SSPPs unit structure at the same size,the considerable advantages in much lower asymptotic frequency with tight field confinement,which enable the proposed filter to be more miniaturization.A high-efficient mode conversion structure is designed to transition from TE-mode to SSPPs-mode by gradient slotline lengths.The low-frequency stop-band can be committed with microstrip to slotline evolution on both sides of the dielectric,while the high-frequency cutoff band is realized by the proposed SSPPs structure.The influence of dispersion relation,electric field distribution,surface current,and structural parameters on the transmission characteristics of the proposed BPF are analyzed by finite difference time domain(FDTD).To validate the design concept,the prototype of the miniaturized SSPPs BPF has been manufactured and measured.The experimental results show high performance of the fabricated sample,in which the working in a range of 0.9 GHz-5.2 GHz with the relative bandwidth is 142%,the insertion loss less than 0.5 dB,the reflection coefficient less than-10 dB,and the group delay is less than one ns.This works provides a mirror for realizing the miniaturization of waveguides,and the application and development of high-confinement SSPPs functional devices in the microwave and THz regimes.

A Cogwheel WGM Resonator Based on Spoof Surface Plasmon Polaritons

The optical WGM resonator plays an important role in modern physics due to its ultra-high quality factor and small volume mode. In optics, SPPs modes can effectively confine electromagnetic waves at the interface between metal and dielectric, providing extremely high sensitivity. New interesting WGM phenomena will emerge when the WGM is combined with the SPPs. In this paper, a cogwheel resonator based on spoof SPPs was designed, which can generate multi-order WGM modes. The transmission coefficients, dispersion relations and resonance modes of the WGM resonator were analyzed. The proposed resonator extends the WGM mode from optical band to microwave band, providing a new perspective for the applications of WGM mode at microwave band.

Polarization-insensitive unidirectional spoof surface plasmon polaritons coupling by gradient metasurface

A polarization-insensitive unidirectional spoof surface plasmon polariton（SPP） coupler mediated by a gradient metasurface is proposed. The field distributions and average Poynting vector of the coupled spoof SPPs are analyzed. The simulated and experimental results support the theoretical analysis and indicate that the designed gradient metasurface can couple both the parallel-polarized and normally-polarized incident waves to the spoof SPPs propagating in the same direction at about 5 GHz.

Spoof surface plasmon-based bandpass filter with extremely wide upper stopband

We investigate the guiding modes of spoof surface plasmon polaritons （SPPs） on a symmetric ultra-thin plasmonic structure. From the analysis, we deduce the operating frequency region of the single-mode propagation. Based on this property, a spoof SPPs lowpass filter is then constituted in the microwave frequency. By introducing a transmission zero at the lower frequency band using a pair of stepped-impedance stubs, a wide passband filter is further realized. The proposed filter is fed by.a transducer composed of a microstrip line with a flaring ground. The simulated results show that the presented filter has an extremely wide upper stopband in addition to excellent passband filtering characteristics such as low loss, wide band, and high square ratio. A prototype passband filter is also fabricated to validate the predicted performances. The proposed spoof-SPPs filter is believed to be very promising for other surface waveguide components in microwave and terahertz bands.

基于SSPPs传感器的金属凹槽填充工件检测

提出了一种基于液体开关控制的人工表面等离激元传感器,用于检测金属凹槽填充密度。该传感器由液体开关控制器和功分结构组成。液体开关由塑料管和带水的注射器组成,固定在SSPPs传感器的分支结构上。塑料管内充满水时,支路不能传输信号,这称为“OFF”状态。相反,塑料管内无水时称为“ON”状态。通过切换传感器支路的“ON”或“OFF”状态,可以控制SSPPs传感器的传感区域。该检测方法是基于凹槽填充质量变化引起的SSPPs传感器反射系数的变化,通过切换支路状态,可以检测各支路下方是否存在填充质量问题。实验结果表明,SSPPs传感器可以有效检测10 mg填充变化,可用于实现批量生产工件的快速筛选。

Single-beam leaky-wave antenna with wide scanning angle and high scanning rate based on spoof surface plasmon polariton

We propose a single-beam leaky-wave antenna(LWA) with a wide-scanning angle and a high-scanning rate based on spoof surface plasmon polariton(SSPP) in this paper. The SSPP transmission line(TL) is etched with periodically arranged circular patches, which converts the slow-wave mode into the fast-wave region for radiation. The proposed LWA is designed, fabricated, and tested. The simulated results imply that the proposed LWA not only achieves a high radiation efficiency of about 81.4%, and a high scanning rate of 12.12, but also has a large scanning angle of 176° over a narrow operation bandwidth of 8.3-9.6 GHz(for |S_(11)| <-10 dB). In addition, the simulated average gain of the LWA can reach as high as 10.9 d Bi. The measured scanning angle range is 175° in the operation band of 8.2-9.6 GHz, and the measured average gain is 10.6 dBi. The experimental results are consistent with the simulation, validating its performance. An antenna with high radiation efficiency, wide scanning angle range, and high scanning rate has great potential for application in radar and wireless communication systems.

基于人工表面等离激元的小型化电可调缺口带滤波器

具有小型化的缺口带滤波器在微波集成系统中具有广泛的应用前景.本文基于倒山形单元的人工表面等离激元(spoof surface plasmon polariton,SSPP)提出了一种新型小型化电可调缺口带滤波器.与相同横向尺寸的传统SSPP单元相比,所提出的倒山形单元的色散曲线表现出更好的慢波特性,渐近频率降低至原来的55%.缺口带的频率可通过调整变容二极管两端的偏置电压来动态控制.随着偏置电压从0.5 V增至30 V,缺口带频率从2.1 GHz移动到2.3 GHz,实现动态调节.仿真结果表明,缺口带滤波器通带内实现了较低的插入损耗(S_(21)<-1 dB)和良好的回波损耗(S_(11)>-10 dB),并且具有小型化的优势,尺寸仅为0.78λ_(g)×0.35λ_(g),λ_(g)是中心频率处的波长.采用印刷电路板技术实际加工了缺口带滤波器.实物测量和仿真结果吻合较好,验证了设计的可靠性.

面向极端环境的石墨烯人工表面等离激元天线阵

面向极端环境中的通信与探测需求,提出一种石墨烯人工表面等离激元天线阵。该天线采用高导电石墨烯薄膜材料制成,结构形式为人工表面等离激元。其中,人工表面等离激元电磁结构分为传输段与辐射段,传输段用以实现显著的慢波特性与场局域性,进而获得低剖面与小型化;辐射段用以实现高定向性的端射辐射,并进行方向图合成。高导电石墨烯薄膜使天线拥有多种物化环境下的耐受性。经仿真与实测验证,天线整体剖面为50μm,在1000次弯折试验、-200~200℃高低温试验、酸性试验、碱性试验、盐雾试验的极端条件试验后,能够提供5.5~6.5 GHz频段范围内S11参数小于-10 dB良好的阻抗匹配,工作带宽内峰值增益为9.3 dBi。

电磁超材料的发展与应用

电磁超材料也被称为新型人工电磁材料,是亚波长尺度单元按周期或非周期排列构成的人工结构,具有传统材料不存在或传统技术难以实现的超常规媒质参数,可对电磁波进行精细调控。超材料是材料、结构、功能的复合体,超越了传统材料的概念和范畴,并已遍布与“波”相关的领域,包括电磁、声学、力学、热学和量子等。近二十年来,电磁超材料一直是物理和信息领域的国际前沿研究热点,由此衍生的相关技术也在通信、雷达和成像等多个领域产生了具有颠覆性效应的一系列应用。

基于人工表面等离子激元的宽带谐振天线

针对传统微带和介质谐振天线(DRA)带宽较窄和尺寸较大的问题,提出了一种基于人工表面等离子激元波导谐振腔的宽带天线。该天线人工表面等离子激元(SSPPs)波导由对称的H型单元结构组成,谐振腔由同轴探针馈电,利用波导单元偶模和奇模两种模式的色散特性,实现了天线带宽的显著增大。该天线工作频段为8.8~12.4 GHz,相对带宽为33.9%。在工作频带内,天线的辐射效率大于92%,最大增益达到了6.8 dBi。此外,天线为低剖面结构,整体尺寸较小,结构简单,利于各种无线通信和传感系统的集成。

宽阻带的人工表面等离子激元微带低通滤波器

针对传统的人工表面等离子激元(SSPPs)微波滤波器的带外抑制水平较弱的问题,设计并制作了一款采用新颖蝶形结构的小型化SSPPs宽阻带微带低通滤波器。首先,通过将传统的微带滤波器中的扇形结构与SSPPs理论相结合,设计了蝴蝶形结构的SSPPs结构单元,实现了较宽的阻带。为了提升滤波器的带外抑制水平,引入了对向箭头形谐振贴片,抑制了所提出滤波器在阻带内25 GHz处的寄生通带。通过仿真模拟单元结构的色散特性,实现了对SSPPs单元的优化设计。设计了一个完整的SSPPs滤波器结构并仿真分析了关键参数对整个滤波器性能的影响。使用F4B板材制作了金属-介质-金属(MIM)结构的该滤波器并对其性能进行了测量。结果显示,该滤波器的3-dB截止频率为10.08 GHz,阻带的最高频率可达33 GHz;通带内回波损耗均高于15 dB,插入损耗最高为2.6 dB;阻带最小衰减在11~35 GHz的范围内最低为22.98 dB,而回波损耗在10~30 GHz范围内基本优于3 dB,且在10~34 GHz范围内最高为4 dB。本设计的测试结果满足设计指标,带外抑制效果理想,可与混频器、信号发生器等器件集成以发挥更好的电路性能。

基于SSPPs的低剖面宽带八木天线阵列设计

提出了一种基于新型人工表面等离子体激元(Spoof Surface Plasmon Polaritons,SSPPs)馈电带有引向器的低剖面宽带八木天线阵列。天线阵列包括两部分:基于人工表面等离子体激元波导的四路宽带功分器和八木天线阵列。人工表面等离子体激元具有高的场局限性,将信号束缚在人工表面等离子体激元的凹槽结构中保证了信号的高效传输,减少了传输损耗。八木天线通过进一步加载引向器结构能够实现端射辐射特性。测试结果表明:天线阵列的回波损耗在4.5~6.05 GHz频率范围内小于-10 dB。天线阵列实际增益在4.5~6.05 GHz范围内最高可达11.1 dBi。

混合基片集成波导的SSPPs带通滤波器设计与实现

人工表面等离子体激元(SSPPs)具有低损耗、高束缚、传输效率高的优点,易于平面集成,并被广泛应用于微波滤波器电路设计。文中在具有高通特性的基片集成波导(SIW)上表面刻蚀具有低通特性的SSPPs结构,将二者有机结合设计出一款混合基片集成波导带通滤波器。仿真结果表明,该滤波器在13 GHz^17 GHz的通带内回波损耗均在-11 dB以下,插入损耗在-1.2 dB左右,在截止频率以外较宽的频带内具有优于-80 dB的优越带外抑制;测试结果和仿真结果高度一致,其回波损耗优于-15 dB,插入损耗在-4 dB左右;通过对平坦和弯曲情况下的滤波器进行对比测试,发现两种状态下的测试高度吻合,证明混合SIW的SSPPs带通滤波器优异的微波特性,并为其在柔性电路的应用提供了研究依据。

Negative-index dispersion and accidental mode degeneracy in an asymmetric spoof-insulator-spoof waveguide

It has been recently demonstrated that negative-index dispersion and mode degeneracy can be achieved by manipulating a spoof-insulator-spoof（SIS） waveguide. In this paper, we propose a new SIS waveguide, which is composed of two spoof surface plasmon polaritons（SSPPs） waveguides drilled with periodic rhomboidal grooves. Both the symmetric and asymmetric cases are investigated. Our simulation results show that the asymmetric SIS waveguides are more significant.By tailoring the tilt of the rhomboidal grooves, the negative-index dispersion can be achieved and the microwave band gap（MBG） can be effectively modulated. At a critical tilt, there appears an accidental mode degeneracy at the edge of the first Brillouin zone. The excitation and propagation of the two coupled modes sustained by the asymmetric SIS waveguides are also demonstrated.

Design and verification of a broadband highly-efficient plasmonic circulator

Circulators play a significant role in radar and microwave communication systems.This paper proposes a broadband and highly efficient plasmonic circulator,which consists of spoof surface plasmon polaritons(SSPPs)waveguides and ferrite disks to support non-reciprocal mode coupling.The simulated performance of symmetrically designed circulator shows that it has an insertion loss of roughly 0.5 dB while the isolation and return loss is more than 12 dB in the frequency range of 6.0 GHz–10.0 GHz(relative bandwidth of 50%).Equivalent circuit model has been proposed to explain the operating mechanism of the plasmonic circulator.The equivalent circuit model,numerical simulations,and experimental results are consistent with each other,which demonstrates the good performance of the proposed plasmonic circulator.

基于人工表面等离激元的小型化微波器件研究进展

人工表面等离激元(Spoof Surface Palsmon Polaritons,SSPP)是由入射电磁波与电磁媒质相互作用,导致媒质表面电子发生集体振荡,所产生的一种表面混合电磁模式,具有波动与粒子的双重性质.在空气一侧,SSPP表现出波动的性质,以电磁波的形式沿媒质界面纵向传输,而在界面法向,场以指数函数衰减;在电磁媒质一侧,SSPP表现为群电子振荡的性质,在法向,场依然按照指数函数衰减;并且,群电子振荡的振幅略小于电磁波波动的振幅.因此,SSPP具有诸多奇特的电磁性质,如场局域特性,深亚波长特性,以及非线性频率色散特性,等等,在微波电胳设计、天线设计、隐身材料与隐身结构设计、电子对抗等领域都具有非常重要的应用价值.文章主要综述了SSPP在小型化微波器件方面的研究进展,包括微波集成电路、滤波器、环形器、传感器、天线、涡旋波发生器等等,为小型化微波器件设计与应用提供借鉴.

基于沙漏形人工表面等离激元和交指电容结构的双频滤波器设计

本文提出了一种在共面波导(coplanar waveguide,CPW)上加载沙漏形人工表面等离激元(spoof surface plasmon polaritons,SSPPs)和交指电容结构的双通带滤波器.首先,在共面波导传输线上引入了沙漏形SSPP单元结构和交指电容结构,以获得高分数带宽、低插损的通带特性.然后,通过加载交指电容环路谐振器激发陷波,形成双通带滤波器.仿真结果表明,所提出的双通带滤波器具有良好的上边带抑制和双通带滤波性能.两个通带的相对带宽分别为46.8%(1.49—2.40 GHz)和15.1%(2.98—3.63 GHz),可在4.77—7.48 GHz的范围内实现超过—40 dB的抑制,且可通过改变相应的结构参数独立调控两个通带的上、下截止频率.为深入了解双通带滤波器的工作原理,给出了相应的色散曲线和电场分布、LC等效电路分析.最后,根据优化后参数数值,加工出滤波器原型实物.实验结果与仿真结果吻合良好,由此表明提出的双通带滤波器在微波频率的集成电路应用中具有重要意义.

一种基于人工表面等离子体激元的小型化低剖面天线

针对高度集成化移动设备对贴片天线小型化与低剖面的需求,提出了一款基于人工表面等离子体激元(SSPPs)的小型化高效率低剖面端射天线,通过在传统孔型单元中引入叉指分支,可有效减小SSPPs传输线的宽度,从而实现天线小型化。该设计结合SSPPs传输线非对称结构和导向枝节结构,实现了天线的端射,并兼具单层低剖属性。实测结果表明,该天线的工作带宽为8.68~9.25 GHz,且在整个工作带宽范围内天线的平均增益和辐射效率分别达到10.05 dB和91.5%。