一种可齐平安装的机载复合结构宽带天线的设计

Design of an Airborne Complex-structural Wideband Flush-mounted Antenna

设计了一种可齐平安装的宽带超高频(UHF)天线。该天线由含有背腔结构的盘锥天线、盘锥顶盘与地板之间的短路结构、以及多板天线3个部分复合而成。这3个部分分别在频率的中端、低端和高端产生3个邻近的独立谐振点,从而有效地展宽了天线的工作带宽。分析了天线各主要结构参数对谐振频点和阻抗带宽的影响,给出了这些参数的最优值,并据此制作了天线样机。测试结果表明,设计的天线在430～845MHz的频带内,驻波比小于2.5,相对带宽为65%,辐射方向图水平全向。同时,该天线具有低剖面结构,整体高度小于最大工作波长的十分之一,在要求齐平安装的飞机和舰船等平台上具有广泛的应用前景。

In this paper, a wideband ultra-high frequency （UHF） antenna which can be flush-mounted is designed. The antenna is composed of three parts; the cavity-backed discone antenna, the short-circuited structure between the top plate of the discone and ground, and the multi-plate antenna. These parts respectively generate medium, low and high resonance frequencies, thus widening the bandwidth of antenna efficiently. The influences of primary structural parameters on the resonance frequencies and impendence bandwidth are analyzed, then the optimal values are given, and the prototype with optimal parameters is fabricated. The measurement results show that the impedance bandwidth of VSWR≤2.5 achieves 65 %, covering a frequency range from 430 MHz to 845 MHz, and the antenna has omni-directional patterns. Meanwhile, the anten- na has very low profile; the overall height of it is less than one tenth of the largest operating wavelength of the antenna. This antenna has great potential in practical applications to aircrafts and vessels where flush-mounted antennas are required.