Conformal antenna array for ultra-wideband direction-of-arrival estimation

Abstract

The design and full-wave analysis of an antenna system for ultra-wideband radio direction finding applications is presented. The elliptical dipole antenna is selected as antenna element due to its robust circuital and radiation properties. The influence of the conformal deformation on the antenna performance has been studied in details. A suitable radome is designed to enhance the antenna front-to-back radiation ratio, as well as to increase the environmental durability of the structure. The considered antennas are optimized for their adoption in two different sub-arrays covering the [250, 950] MHz and [0.9, 3.3] GHz frequency bands, respectively. A uniform circular array (UCA) with five elements is used for the array topology. The full-wave analysis of the whole array structure is carried out in order to evaluate the coupling between the antenna elements. In particular, a novel calibration technique is developed in order to compensate for the mutual coupling between the array elements, possible variations in the antenna characteristics, and the effects of the array bearing structure. The performance of the designed array in terms of direction-of-arrival estimation is thoroughly analyzed and discussed.