High gain and circularly polarized substrate integrated waveguide cavity antenna array based on metasurface

Two substrate integrated waveguide (SIW) cavity antenna arrays based on metasurface are proposed in this paper. By rotating the metasurface element, circularly polarized and high gain antennas are achieved respectively. Firstly, multi-mode resonance theory is employed to broaden the bandwidth of the slot antenna. And then, an SIW cavity composed of 4×4 cornercut elements is added on the top of the slot antenna to achieve the circular polarization and improve the front-to-back ratio. Thirdly, the metasurface elements are sequentially rotated and a high gain antenna with 2-dBi enhancement on average in the operation band is obtained. Based on the two antenna units, two 2×2 antenna arrays are designed. The circularly polarized and high gain antenna arrays are both fabricated to verify the correctness. Furthermore, the novel wideband phase shifter is employed in the circularly polarized antenna to obtain an operating bandwidth of 38% (4.05 GHz-5.95 GHz) and AR bandwidth of 24.9% (4.4 GHz-5.65 GHz). The bandwidth of the high gain antenna can reach 42.7% (3.95 GHz-6.1 GHz) and with the gain enhancement of 2 dBi compared with that of the circularly polarized antenna. The gain remains steady in most of operating band within a variation of 1 dBi. It is remarkable that the rotating of the metasurface element has a great influence on the antenna performance, which provides a new explication for the multi-function antenna design.     

一种兼有高增益和宽带低散射特征的波导缝隙天线设计

设计了一种同时具备高增益和宽带低散射特征的波导缝隙天线.将蚀刻有互补开口谐振环的方形贴片人工磁导体正交布阵得到宽带低雷达截面积(RCS)反射屏并以之代替原天线的全金属反射板,通过优化反射屏的加载方式,在展宽天线工作频带、提高天线增益的同时,实现了宽频域范围内天线鼻锥方向RCS减缩.实测结果表明:加载低RCS反射屏的缝隙天线工作带宽增加了100 MHz,前向增益提高了3.2 dB,在5.52—6.63GHz范围内RCS减缩量达10 dB以上,减缩带宽达到20%.     

W波段基片集成波导缝隙阵天线的研究

介绍了一种低成本高效率的W波段4×4基片集成波导(SIW)缝隙阵天线。天线阵为双层结构,上层为辐射层,采用宽边纵向偏移缝隙驻波阵,可以实现高的辐射功率,下层为馈电层,采用SIW串联缝隙馈电方式,减小了传统功分网络带来的传输损耗和实现难度。对天线阵进行了优化设计,采用标准低成本PCB工艺制作了天线阵实物样品并进行测试。测试结果与仿真结果吻合较好,天线阵在94 GHz时,最大增益为16.8 dB,反射系数-30.1 dB,-10 dB带宽为92.6~96 GHz,副瓣电平19.5 dB,天线阵口径效率为83%。     

Novel Broadband Reflectarray Antenna with Windmill-Shaped Elements for Millimeter-Wave Application

A novel broadband millimeter-wave reflectarray antenna composed of windmill-shaped elements of variable lengths is proposed. Compared to the conventional single-layer reflectarray elements, the windmill-shaped elements can realize much larger phase variation range (over 600°), leading to broader bandwidth. Using this technique, a 15°-beam-steering reflectarray operating at 30 GHz is designed. The computed results demonstrate the agreement of the main beam steering with the design requirement, and a 1-dB gain bandwidth close to 20% is obtained. The validity of the obtained results is verified by comparing the ones generated by Ansoft High Frequency Structure Simulator (HFSS) with those produced by Ansoft Designer. The antenna is useful for millimeter-wave applications. This work was supported by the National Natural Science Foundation of China (No. 90505001), the High-Tech Research and Development Program of China (No. 2006AA01Z275), and the Creative Research Group Program of UESTC.     

基于极化转换超表面的宽带低雷达散射截面缝隙天线阵

提出了一种利用极化转换超表面(PCM)来缩减雷达散射截面(RCS)并保持缝隙天线阵列辐射特性的新型天线,在不影响天线性能的情况下实现了天线的宽带RCS缩减。该PCM由45°倾斜的开槽矩形贴片周期排布构成,它被放置在缝隙阵列天线的上表面,起到RCS缩减的功能。分析了RCS缩减的特点和原理,仿真和实验结果表明,带有PCM的缝隙天线阵在x极化和y极化波冲击下,单站RCS缩减带宽为8.0～21.8 GHz。同时天线的辐射特性在阻抗带宽、增益和辐射模式等方面都能保持良好性能。     

基于极化旋转超表面的圆极化天线设计

本文通过设计出一种反射型极化旋转超表面,在8—12 GHz频域内实现高效的极化旋转,并将其加载于微带缝隙天线下方构成新型的极化旋转超表面天线,利用超表面的90°极化旋转效应,成功实现了天线的圆极化辐射调制.仿真与实验结果表明:圆极化天线的中心工作频率为GHz,阻抗带宽为8.3—10 GHz.当微带缝隙天线与极化旋转超表面的间距H=4.5mm时,天线在8.3—8.8 GHz频带内实现了圆极化辐射;当mm时,天线在8.8—9.3 GHz频带内实现了圆极化辐射;当=8mm时,天线在9.3—10 GHz频带内实现了圆极化辐射.实验结果与仿真结果相符,证明了此种设计方法的有效性,也为微带缝隙天线的圆极化设计提供了一种新的途径.     

Planar oscillators for monolithic integration

Planar oscillators for monolithic millimeter-wave integrated circuits are considered, and a design based on a coplanar-waveguide resonator is described. Design data are obtained from simulation at 1 GHz. the resonator has a Q of 195 (50 when scaled to 100 GHz) and is mechanically tunable over a range of 12%. Combining this resonator with a Gunn diode, a model oscillator is obtained. Output is obtained quasi-optically through a transmitting antenna. Twenty one milliwatts of output at 4.5 GHz are obtained with high spectral purity. A 100 GHz monolithic planar oscillator based on this design should be possible.Research supported by the U.S. Army Research Office Contract DAAG29-79CO134, the National Science Foundation under Grant ECS-8116018, and the Joint Services Electronics Program (AFOSR Contract F49620-79-C-0178).     

用于宽带高功率微波辐射的双层贴片天线特性

 研究了用于宽带高功率微波辐射的双层贴片微带天线输入阻抗带宽和辐射特性,提出一种适合于高功率微波辐射的圆锥传输线馈电结构以减小传统馈电探针的引线感抗,使天线的功率容量提高到百MW级,同时作为同轴线到径向传输线的过渡变换,使反射系数降低近50%。通过数值计算分析了不同的介质基底厚度组合和贴片尺寸对天线带宽的影响,优化参数后的天线带宽达到了34.9%(电压驻波比小于3),带内平均增益高于6.5 dB,最大增益8.3 dB,主辐射方向上的远场辐射因子与馈入宽带脉冲幅度比值大于1.3。分析了天线的功率容量,模拟计算表明该天线可用于辐射幅值300 kV的宽带高功率微波。     

Design of 45-degree Linearly Polarized Substrate Integrated Waveguide-fed Slot Array Antennas

This paper presents a method of designing substrate integrated waveguide-fed (SIW-fed) slot array antennas. The design theory is based on the circuit model of slot and via as well as the reflection canceling. To prove the feasibility of this method, a 10-element K-band SIW-fed 45-degree linearly polarized slot array antenna with uniform power distribution is designed. By full-wave simulation, the antenna has a good impedance bandwidth of 7.5% and uniform power distribution. Besides, a maximum gain of 15.3dBi is obtained in the broadside and the cross polarization is suppressed below -23.5dB in the boresight. This type of SIW-fed slot array antennas can be a good candidate for microwave and millimeter-wave applications, especially for auto-motive collision-avoidance radar systems.     

基于缺陷接地结构的太赫兹双频微带天线

提出了一种工作在太赫兹频段的双频微带天线。在普通矩形微带天线的基础上,在辐射贴片上加载45°和135°的矩形贴片增大辐射面积,增大高频谐振点处阻抗带宽。通过引入缺陷接地结构使得天线在接地板处的电流路径改变,并与辐射贴片相互耦合,从而实现双频特性。为提高天线增益,在辐射贴片边缘加载若干寄生矩形贴片,并增加了寄生贴片处的基板厚度。该款天线可以同时在520 GHz(508~532 GHz)和680 GHz(581~766 GHz)的频段下工作,其中高频段的相对带宽达到了27.5%,最大增益达到了3.54 dB和4.11 dB。该双频天线结构相对简单,各项性能指标稳定,对于工作在太赫兹频段上的通信系统和无线传输系统具有一定的应用价值。     

Design of Low-Profile Millimeter-Wave Substrate Integrated Waveguide Power Divider/Combiner

A low-profile millimeter-wave substrate integrated waveguide (SIW) power divider/combiner is presented in this paper. The simplified model of this compact SIW power dividing/combining structure has been developed. Analysis based on equivalent circuits gives the design formula for perfect power dividing/combining. In order to verify the validity of the design method, a four-way SIW power divider/combiner circuit operating at Ka band is designed, fabricated and measured. Good agreement between simulated and measured results is found for the proposed passive power divider/combiner. Experiments on the four-way passive divider/combiner back-to-back design demonstrate a minimum overall insertion loss of 1.5 dB at 31.1 GHz, corresponding to a power-combining efficiency of 84%. The measured 10-dB return loss bandwidth is demonstrated to be 2.2 GHz, and its 0.5-dB bandwidth was 2 GHz.     

Theoretical and experimental researches on C-band three-cavity transit-time effect oscillator

In recent years great progress has been made in the plasma technology, pulsed-power technology, and the PIC simulation tools. At the same time, great efforts have been made in the research of the directed energy weapon. As a result, the technol-ogy of the high power microwave (HPM) has been developing rapidly[1]. Over the past 30 years, dozens of HPM sources have been found, with the maximum peak power reaching 15GW, the maximum energy of the single pulse 600 J, and the frequency stretchi…     

一种新型宽带定向性贴片天线设计

利用超材料概念,通过在接地面上蚀刻条形缝隙图案,并引入"八木"天线中的反射器和引向器的设计思想,设计并且制作了一种超宽带强定向型贴片天线.仿真结果表明,天线相对带宽为65.3%(6.9—13.6 GHz),带内回波损耗均在-10 d B以下,整个频段内天线的增益均在4.4 d Bi以上.由于接地板上蚀刻的超材料结构的左手特性影响了天线介质基底的等效媒质参数,天线电磁场的传播方向被改变,天线辐射场主要集中在水平方向而不是传统贴片天线的垂直方向.在传统的贴片天线上引入反射器和引向器增强了天线的方向性.实验结果与仿真结果有较好的一致性.     

2.4/4.8/7.2 GHz三频段谐波雷达天线的研究与设计

研究设计了一种应用于手持式谐波雷达的三频段单极子天线。天线采用共面波导馈电,通过在单极子天线主辐射体加载L型辐射枝节、在接近主辐射体的接地平面开三角形切口的方法,使其谐振于2.4 GHz,4.8 GHz和7.2 GHz三个频段。同时,在距离天线10 mm处加载金属挡板,使天线辐射方向性增强,并能接收多个方向反射的电磁波。所实现的天线尺寸为54 mm×53 mm×1.6 mm,在三个工作频段上的带宽分别为0.51 GHz(2.35～2.86),1.39 GHz(4.17～5.56),1.46 GHz(6.17～7.63),能够有效覆盖谐波雷达全部的工作频段;由天线的峰值增益和辐射方向图可知,天线在工作频段内增益性能和整体辐射性能良好。     

利用互补天线原理求解孔缝的共振性能

 利用互补天线原理从理论上推导了真空、介质窄缝的共振频率公式,在理想窄缝长度小于5倍波长、辐射角度偏离垂直方向小于30°的情况下,孔缝的共振频率点仍然可以用半波振子的辐射情况来解释,共振点满足孔缝长度等于入射波的半个波长;介质窄缝等效为半个孔缝深度的微带贴片天线,不同介电常数介质填充时的共振频率理论公式推导值和数值模拟值基本一致,相对误差在5%以内。进一步分析了窄缝阵列的耦合性能,结果表明互补天线原理可以很好地应用于分析和求解孔缝的共振性能。     

一种基于油介质开关振荡器的紧凑宽带高功率微波源

紧凑宽带高功率微波源研制过程中，为了提高工作电压，开关振荡器采用变压器油作为绝缘介质。研制了一种具有较小几何尺寸和前向辐射方向图的组合振子天线作为辐射天线。在设计阶段，采用电磁仿真软件对开关振荡器和辐射天线的性能进行了仿真和预测。然后，对该宽带高功率微波源进行了实验研究，并对辐射场进行了测量。结果表明:开关振荡器的工作电压超过300 kV，辐射场rE值(距离和辐射电场峰值的乘积)达到125 kV；辐射场中心振荡频率为375 MHz，3 dB带宽为24%。     

Efficacy of a wideband flexible antenna on a multilayer polymeric nanocomposites Fe3O4-PDMS substrate for wearable applications

The recently introduced polymeric nanocomposites substrate layer technology is used in the design of a flexible antenna array for wearable applications. This new technology allows a considerable widening of the bandwidth of classical microstrip topologies. This means that a relatively wide band can be combined with a full ground plane in a very simple structure, which is an ideal combination in wearable applications. The wideband and flexible features enabled the antenna to mitigate body-detuning effects. The proposed antenna prototype consists of a 2 × 2 array of rectangular patch elements with dimensions of 70 × 70 × 4.2 mm³. The measurements are performed in free space, and on-body under bent conditions. The antenna working within the frequency band of 5 GHz–8.2 GHz, with a fractional impedance (FBW) bandwidth of 50.34%. The antenna demonstrates a maximum radiation efficiency of 60%, and 9.8 dB of realized gain. Since this antenna is intended for on body-centric wireless communication application, the specific absorption rate is evaluated when the antenna is placed on the right arm of a realistic human phantom. The performances and features of the proposed antenna paved the way for off-body connections in a WBAN and wearable applications including WiFi, telemedicine and Vehicle-to-Everything (V2X).     

Metamaterial-embedded dual wideband microstrip antenna for 2.4 GHz WLAN and 8.2 GHz ITU band applications

ABSTRACT

A compact dual-band antenna designed for operating in IEEE 802.11b/g WLAN (2.4–2.484?GHz) and ITU frequency bands (8.01–8.5?GHz) is presented in this communication. The antenna has two distinct resonant modes generated with the help of three U-shaped transmission lines and a modified ground plane. A periodic repeating pattern of metamaterial unit cells integrated on the same plane of the substrate has enhanced the antenna performances using improved loading method. The measured bandwidth of the metamaterial-embedded antenna is increased by 16% in the lower operating band and 6% in the upper operating band. The compact proposed antenna provides wide measured bandwidths of about 40% (2–3?GHz) in the lower and 16% (8.19–9.63?GHz) in the upper frequency spectra. The maximum measured gain of the proposed antenna is increased around 3.63?dB at 2.36?GHz and 1?dB at 8.45?GHz. The proposed antenna radiator is about 89.6% compact with respect to a conventional antenna. An excellent agreement of the simulation with the benchmark results validates the design of the proposed structure.     

一种兼具宽带增益改善和宽带、宽角度低雷达散射截面的微带天线

设计并制备了一种兼具高增益和低雷达散射截面(radar cross section, RCS)的微带天线, 通过给原始微带天线加载双屏频率选择表面(frequency selective surface, FSS)覆层, 使其具有宽带的3 dB增益带宽和宽带、宽角度的低RCS特性. 该FSS单元的上层是四个开口处都焊有电阻的金属环结构, 下层是中间和四边都开缝的金属贴片结构. 上层加载的电阻主要用于吸收雷达入射波, 减缩天线RCS; 下层的贴片和天线地板构成Fabry-Perot谐振腔, 提高天线增益. 在5.75–11.37 GHz频带内, S₂₂<-10 dB, S₁₂<-10 dB; 在11.21–11.54 GHz频带内, S₁₁反射系数相位曲线斜率为正, 幅度模值均在0.86以上. 实验结果表明: 与原始天线相比, 在谐振频点11.73 GHz处, 天线增益提高3.4 dB, E, H面的半功率波束宽度分别减小16°和50°; 天线的3 dB增益带宽为10.00–12.40 GHz, 完全覆盖阻抗带宽. 在4.10–11.30 GHz 频带内, 天线法向RCS均有3 dB以上的减缩, 最大减缩23.08 dB; 4.95 GHz处的单站RCS在-20°–20°的角域、双站RCS 在-37°–37°的角域均有3 dB以上的减缩. 实验结果证实了该FSS覆层可用于同时改善天线的辐射和散射 性能. 关键词： 频率选择表面 低雷达散射截面 高增益 宽带