超表面加载极化可重构双极化微带天线设计

基于超表面结构设计了一种2.555~2.655 GHz频段的极化可重构双极化微带天线。首先根据微带天线理论设计了缝隙耦合正交馈电的双极化微带贴片天线,然后提出并设计了一种方形切角的新型超表面结构,并将该超表面放置在双极化微带天线上,通过机械方式旋转超表面,实现了左、右旋圆极化和水平、垂直线极化之间的极化转换。利用HFSS仿真软件对该超表面加载微带双极化天线进行了仿真。结果表明,该双极化天线能够便捷地实现极化转换,且在两种极化状态下,天线在工作频带内的回波损耗小于–10 dB,隔离度大于20 dB,圆极化工作状态下的轴比小于3 dB,天线的整体性能良好。     

极化可变可重构微带天线

设计了一种单点馈电的小型微带正方形贴片开槽天线,通过控制二极管的开关状态改变贴片上两个相互正交开槽的状态,可以实现左旋与右旋圆极化的切换.文中给出了Ansoft HFSS9.0的仿真结果和实测结果.仿真与测试结果表明,这种极化可变可重构微带天线具有较好的圆极化特性,可以应用于无线通讯与卫星通信领域.     

宽带极化与方向图可重构天线研究

随着无线通信系统的快速发展, 宽带可重构天线将在未来发挥巨大作用.文中综述了四种宽带极化与方向图可重构天线, 它们都具有提高通信系统容量, 消除极化失配, 扩大辐射范围等特点.首先介绍了一种宽带的多线极化可重构天线.此款天线基于L型探针馈电的贴片天线, 实现了0°, 45°, 90°以及—45°极化的选择, 具有宽带、低剖面、高增益的特点.其次, 同样基于L型探针馈电的贴片天线, 通过引入一个输出相位可重构的功分馈电网络, 实现了宽带的圆极化可重构天线, 其同样具有宽带、低剖面、高增益的特点.除了极化可重构天线, 文中还介绍了两款方向图可重构天线, 可分别实现线极化以及圆极化的全向锥状波束以及定向辐射波束的方向图可重构.前者是基于宽带的单极子贴片天线跟L型探针馈电的贴片天线的有机结合.后者是基于环缝隙的贴片天线配合激励端口可重构的功分馈电网络的组合.此两款天线均具有结构紧凑、宽带、增益稳定的特点.     

双频段双圆极化共孔径天线研究

通过利用多层混合介质层叠和空间孔径布局的方法,设计了一种双频段双圆极化共孔径的微带天线。该天线利用3 dB电桥作为馈电网络,选择双点馈电的结构形式在UHF频段实现了右旋圆极化;同时天线为了覆盖S频段,采用双层结构、双点馈电的天线阵元实现左旋圆极化,使用旋转布阵的方式优化阵列的圆极化轴比。对天线进行了仿真,加工和测试,实测结果和仿真结果吻合良好,验证了这种方法设计的双频段双圆极化共孔径天线的正确性和可行性。     

一种基于电调移相器的可重构天线

设计并实现了一种基于反射式移相器的极化可重构天线。该天线使用一对交叉摆放的领结型振子作为辐射单元,并在馈电网络中通过两路移相器调整双馈端口间的相位差实现线极化、左旋圆极化和右旋圆极化模式之间的切换。通过加载匹配枝节的方法扩展了反射式移相器的移相范围,提高了移相器的移相精度,降低了天线圆极化模式带内的轴比。所设计天线的中心频率为5.4 GHz,在线极化模式下10 dB 阻抗带宽为990 MHz,在圆极化模式下10 dB 阻抗带宽分别为760 MHz 和850 MHz,3 dB 轴比带宽分别为510 MHz和480 MHz。该天线在频带内具有稳定的波束方向图,其平均增益为5.3 dB,并且具有27 dB 的主极化-交叉极化隔离。最终的实测结果与仿真结果基本一致,表明该天线具有良好的性能。     

一种小型化双频双圆极化天线北大核心CSCD

本文设计了一款小型化单层单馈的双频双圆极化天线。在已有双偏心圆环天线结构研究的基础上,通过开槽来改善天线性能。本文设计的天线由两个尺寸不同的偏心圆环组成,在耦合馈电的对称圆环天线基础上改变内外圆心位置,从而改变其电流的分布,实现左旋或右旋圆极化。通过在圆环上蚀刻弧形槽来改变电流路径,从而改善轴比带宽。利用同一个弧形微带馈电线对两个非对称的圆环激励,实现馈电和阻抗匹配。经过仿真验证,本文提出的双圆环开槽天线在25.6GHz和37.1GHz处分别实现左旋和右旋圆极化。     

四维多极化天线阵

针对通信感知一体化应用,利用四维天线阵技术实现了能够同时辐射多个极化波的新型天线阵。该天线阵列由四维天线阵馈电网络和4端口圆环阵列组成。四维天线阵特有的时间调制特性可以在不改变天线结构且不引入移相器的情况下,在中心频率产生垂直极化全向辐射波束,在第一边带产生左旋圆极化定向辐射波束,在负一边带产生右旋圆极化定向辐射波束。相比于传统极化可重构、波束可重构天线,四维天线阵结构简单,且三种极化状态和两种辐射波束可以同时实现,更好地满足多功能一体化系统需求。     

Ka波段圆极化平板阵列天线设计

本文设计了一种规模为 8×8 的 Ka 波段圆极化平板阵列天线。2×2 子阵为一个圆极化基本单元,子阵馈电方波导腔体中插入极化膜片形成圆极化特性,使用全并馈 E 面波导功分网络对 16 个子阵实现等幅同相馈电。设计的阵列天线实现了良好的圆极化特性与高增益特性。     

新型共口径双频双圆极化微带天线设计

论述了一种共口径双频双圆极化微带天线的设计方法。通过工作于主模和高次模的两辐射贴片嵌套来实现双频双圆极化辐射和满足双馈电端口高隔离度的要求。依据此设计方法按照内外贴片不同频段分配研制了两种天线实物样机,并对天线样机的电性能进行了测量,测量结果表明,天线在两频段上圆极化性能良好,并且双端口隔离度高于35dB,证明了此设计方法的有效性。     

一种方向图可重构圆极化阵列天线的设计北大核心CSCD

为了实现天线波束的灵活重构和调控,提出了一种方向图可重构圆极化阵列天线。阵列天线选用L型探针耦合馈电以拓宽阻抗带宽和圆极化轴比带宽,并基于提出的相位变换器设计输出端口间相位差可调的馈电网络。通过控制馈电网络中相位变换器上各PIN二极管工作状态,实现了天线的主辐射波束指向在+40°,+15°,-15°和-40°角度间切换。实测结果表明,该阵列天线在四种工作状态下的重叠阻抗带宽约为22%(2.2~2.74 GHz),重叠轴比带宽约为12.2%(2.33~2.62 GHz),且圆极化峰值增益为6.48 dBi。     

MEMS开关可重构矩形缝隙环天线的设计

提出一种基于MEMS开关的可重构矩形缝隙环天线设计.其关键部件之一是射频微波MEMS开关,选取了接触式MEMS开关.该天线为用共面波导馈电的多频率可重构天线,通过多个MEMS开关来改变矩形缝隙环天线的拓扑结构,按照一定的规则控制开关可实现多频率可重构.其结构简单,剖面低,易于与电路集成.     

Dice‐Five Polarization‐Agile Corner‐Fed Patch Array Antenna

A novel planar polarization‐agile microstrip subarray is proposed and its performance assessed by a thorough numerical investigation. The subarray consists of five square patches with a central element, directly coupled to a pair of microstrip feed lines by a cross‐shaped aperture, which spreads the power outwards to the other patches through a network of suitable connections. By properly exciting the antenna at its input ports, any kind of polarization of the radiated field can be accomplished with fairly low cross‐polarization levels. Moreover, since only two feed lines are required to drive the whole subarray, polarization agility is simply and attractively achieved by a single phase‐shift circuit. The design concept is described and the results of the analyses and simulations performed by two completely independent full‐wave approaches are presented and discussed.     

短波水平极化测向中的交叉极化波

通过对水平偶极子和定向天线的计算,分析了水平天线对主极化波和交叉极化渡不同的幅相响应特性,并讨论了到达接收点的两个正交极化波之间的相关性和相干性,进而讨论了交叉极化波对水平极化测向精确度的影响.     

Bandwidth and frequency agile MIMO antenna for cognitive vehicular communications

A reconfigurable MIMO antenna for heterogeneous vehicular networks is reported in this paper. The frequency and bandwidth characteristics of the MIMO antenna can be reconfigured to meet multi-standard and multi-frequency requirements in automobiles. The antenna element evolved from an edge-chamfered ultra-wideband (UWB) antenna operating from 2.1 to >15 GHz. The bandwidth reconfiguration is achieved through the selection of excitation paths connecting the feed and radiator. The feedline selection is performed using PIN diodes, making the antenna operate in three distinct modes, namely, UWB mode (Mode 1: 2.1–>15 GHz), industrial, scientific and medical/Internet of Things (ISM/IoT) mode (Mode 2: 2.45 GHz), and wireless local area network (WLAN) mode (Mode 3: 5–6 GHz). The feed path corresponding to Mode 2 and Mode 3 is incorporated with a suitable filtering network to shape the frequency response of the antenna based on the user's requirements. Owing to the requirement of cognitive selection of frequency bands, the frequency tunability in Mode 2 is realized using varactor diodes. The varactor-incorporated feed path reconfigures the center frequency between 2.45 and 3.5 GHz. The proposed MIMO antenna offers gain and total efficiency greater than 2.94 dBi and 76%, respectively. The prototype of the 4-port MIMO antenna is being fabricated to test its functionality in real time.     

A Novel Single-Feed Circular Microstrip Antenna With Reconfigurable Polarization Capability

A single-feed circular microstrip antenna with reconfigurable polarization capability is proposed. This antenna has a simple structure, which consists of a radiating circular patch, five switches (PIN diode), three matching stubs, and a 50 microstrip feed line. It can be switched between 4 different states: two states (low-frequency and high-frequency) for linear polarization (LP), one state for left hand circular polarization (LHCP) and one for right hand circular polarization (RHCP) by controlling the bias voltage of two PIN diodes. At the same time, three switchable matching stubs are used for matching every polarization state. Simulation results and experimental results show that the proposed antenna demonstrates a low cross polarization level, good impedance bandwidth, and a very good axial ratio in the circularly polarized states.     

微带线-槽线馈电缝隙等角螺旋天线设计

被动雷达导引头为探测与跟踪目标可采用宽带等角螺旋天线,针对降低等角螺旋天线剖面,该文提出一种低剖面背腔式微带线-槽线馈电缝隙等角螺旋天线。微带线-槽线巴伦(Balun)中渐变微带线将同轴线激励的不平衡电场最终转化为槽线处平衡电场。实测结果表明,该缝隙等角螺旋天线实现了1:9的电压驻波比(VSWR)带宽,良好的辐射方向图与圆极化特性。在天线背面加入高度仅有0.05L(L为最低工作频率所对应自由空间中波长)的反射腔,腔内放置矩形环状吸波材料,有效拓展了天线低频段带宽。测试结果表明带有反射腔的缝隙等角螺旋天线实现了1:6.4的电压驻波比带宽,天线增益大于4 dB,良好的圆极化与方向图特性。平面化、一体化的馈电方式与低剖面反射腔有效降低了缝隙等角螺旋天线剖面,测试结果验证了该文所提出的微带线-槽线巴伦馈电缝隙等角螺旋天线设计方法的有效性。     

Electromechanical controlled phased array dumbbell EBG beam steerer

A steerable phased array antenna driven mechanically is realized by utilizing the variation of dumbbell electromagnetic bandgap (EBG) structures. The variation takes place under the feed line of a 4-element array that gives the change in relative phase shift. The phase shift achieved from different shaping combinations of EBGs shifting under the feed lines. The feed lines are connected with four microstrip patches to yield a 4-element phased array antenna. The mechanical controlled pattern shapes of phase array antenna are simulated in electromagnetic (EM) software Zeland IE3D. Finally the design is fabricated with the help of optical lithography. It can be seen that the beam steering angle can be controlled mechanically without phase shifter and PIN switches.     

新型RF-MEMS可重构分形天线

设计了一种新型的集成RF-MEMS开关的混合分形可重构天线,该天线为加载了1阶Koch曲线的1阶Sierpinski三角垫片结构.仿真结果表明:所设计的天线在MEMS开关全闭合和全断开的状态下分别具有多个不同的工作频带.详细地分析了天线的重构特性,按照仿真模型在高阻硅片上运用微电子工艺制作出了天线样品.对样品进行了测试,最后比较和分析了测试结果.     

微带磁流振子天线综述

文章综述了微带磁流振子天线的最新发展情况,从理论上对比了微带磁流振子天线和电流振子天线的辐射机理,阐述了微带磁流振子具有水平极化和高增益的新颖性,最后介绍了微带磁流振子在新型天线阵列、圆极化天线、高增益天线的应用。