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

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 circularly-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°.