Digital Beamforming and Nulling in Conformal Antennas Using Software Defined Radio

Conformal antenna arrays are of significant interest for automotive and aerospace applications. Such arrays can be conformed to the surface of vehicles and aircraft while providing minimum impact on aerodynamics. However, the design and analysis of such antenna systems differs from the planar case. Also, beamforming and nulling for curved antenna arrays with directional elements requires modification of the beamforming and nulling algorithms. Here, a linear array of four elements is considered on a curved surface. Instead of using traditional beamforming with phase shifters, software defined radio (SDR) is used. A method is proposed to achieve adaptive beamforming and nulling of the flexible array, by using a SDR platform to feed the antenna array, in various conformed configurations. Minimum Variance Distortionless Response (MVDR) beamforming is used and adapted to the conformal antenna. Experimental results show good agreement with simulations.