低互耦星载相控阵天线设计

摘要

Design of a phased array antenna with lower mutual coupling for the satellite application operating in Ku band is introduced in this paper.By loading the metal cavity around the array element,the mutual coupling effect can be reduced and then improve the scanning performance of the phased array antenna.With this method,the characteristics of phased array antenna with ±60° scanning in two dimensions are analyzed.To verify this design,5×5 subarray and 16×16 array are studied.The measured results show that the mutual coupling between the elements is less than-16dB.The array element has an impedance bandwidth (VSWR≤2) of 11％ (15.1-16.8 GHz).In addition,within the bandwidth of f0 ± 500 MHz,the E-plane of the radiation pattern has a 3dB beam-width of more than 113° and a 5 dB beam width of more than 122°,while the H-plane has a 3 dB beam-width of more than 98° and a 5 dB beam-width of more than 113°.Based on the simulation,a prototype of the 5 × 5 array antenna is fabricated herein.The measured results agree well with the simulated ones,which proves the effectiveness of the design.The beam width of the proposed element fully meets the requirement of a phased array antenna with a ± 60° scanning range and can be used in phased radar system.%介绍了一款工作于Ku频段的低互耦星载相控阵天线的设计方法,采用在阵列单元周围加载金属腔体的方式降低阵列单元之间的互耦效应,从而改善相控阵天线的方向图扫描特性.针对相控阵天线在二维±60°范围内低副瓣波束扫描的特点,对5×5子阵和16×16阵列进行了研究,验证了阵列的互耦降低方法的有效性和电性能.研究结果表明:相控阵单元间互耦小于-16 dB,而相控阵单元在15.1～16.8GHz电压驻波比小于2,相对带宽11％;在频率为f0±500 MHz范围内,E面3 dB波束宽度大于98°,5 dB波束宽度大于113°,H面3 dB波束宽度大于113°,5 dB波束宽度大于122°.在仿真设计的基础上,研制了子阵天线试验样机,测试结果与设计结果吻合良好,证明了降低互耦方法的有效性,天线单元方向图满足在±60°范围内波束扫描的要求,可应用于相控阵雷达系统.