A 26.1:1 Bandwidth Ultrawideband low-profile Tightly Coupled Dipole Array

This design presents a novel tightly coupled dipole array (TCDA) with a bandwidth of 26.1:1 (VSWR < 3) in the 0.20-5.22 GHz band. By adding a new dual-stopband resistive frequency selective surface (RFSS) between the TCA and the floor, the short-circuit points formed by the floor at the frequency points corresponding to λ = 2h and h (h is the height from the antenna to the floor) are both eliminated. By placing a specific wide-angle impedance matching (WAIM) above the antenna, the impedance bandwidth and beam scanning ability of the new dipole antenna are further improved under the premise of ensuring lightweight and a low profile of 0.05 λlow. Simulation and experimental results show that the designed TCA has extremely wide bandwidth, good directivity and wide-angle scanning characteristics. Compared with previous designs, it greatly extends the bandwidth and improves the gain.

本设计提出一种新型紧耦合偶极子阵列（Tightly Coupled Dipole Array, TCDA），其在0.20~5.22 GHz频段内可实现26.1:1的工作带宽（电压驻波比VSWR < 3）。通过在紧耦合偶极子阵列与接地板之间增设一款双阻带电阻型频率选择表面（Dual-stopband Resistive Frequency Selective Surface, RFSS），本设计消除了接地板在对应于λ=2h与λ=h（h为天线至接地板的高度）的频率点处形成的短路点。在天线上方布设特定的宽角阻抗匹配（Wide-angle Impedance Matching, WAIM）结构后，本设计在保证天线轻量化且剖面高度仅为0.05λ_low（λ_low为最低工作频率对应的波长）的前提下，进一步提升了该新型偶极天线的阻抗带宽与波束扫描能力。仿真与实验结果表明，所设计的紧耦合偶极子阵列具备超宽带宽、优异的方向性以及宽角扫描特性；相较于此前的设计方案，本设计大幅拓展了工作带宽并提升了天线增益。