一种低剖面宽带二维宽角扫描圆极化阵列天线

A low profile and wideband circularly-polarized array antenna with 2D wide-angle scanning

针对现有圆极化平面阵列的扫描角受限和三维宽角扫描阵列体积大的问题,设计了一种基于阵因子方向图和单元因子方向图互补的低剖面宽角扫描圆极化阵列天线.该阵列单元采用新型圆极化正交偶极子天线,并由其组成多个圆环子阵,每一子阵内单元的法向均偏离阵列法向一个固定倾角并等间距排布在"涟漪"状金属地板上.这种阵列排布方式使得在主波束扫描至大角度时天线单元因子增益可以补偿阵因子的增益下降.设计的一个64元阵列天线的实测结果表明:在8~9GHz工作带宽内,且波束扫描覆盖0°~±62°,各阵元的有源驻波比均小于2.1,中心频点扫描增益起伏小于1.71dB,扫描波束的圆极化轴比小于2dB.

In order to overcome scanning angle limitation of planar array and bulky volume of three- dimensional wide-angle scanning array, we propose a low profile ripple-shaped wide-angle scanning circu- larly-polarized array based on the compensation method of array factor pattern and element factor pattern. This array is composed of several ring subarrays, which include different numbers of novel circularly- polarized crossed dipoles, and the element normal of each ring subarray deviates from array normal with a fixed angle. These ring subarrays are aligned on the surface of a ripple-shaped ground plate. Based on this array structure, the element gain can compensate the array gain degradation when array main-beam steers to a large angle. An array with 64 elements is designed and fabricated, and the measured results show that the active voltage standing wave ratio （VSWR） of the array elements are less than 2.1, the scanning gain fluctuation of center frequency is less than 1.71 dB, and the axial ratio （AR） is less than 2 dB, when the operation frequency range is 8--9 GHz and scanning angle is from 0° to ±62°.