A Compact Ultrawideband Antipodal Vivaldi Antenna and Its Efficacy in Through-Wall Imaging

An ultrawide band (UWB) antipodal Vivaldi antenna (AVA) is presented in this paper for through wall imaging application. The traditional Vivaldi antenna is modified by introducing asymmetric elliptical slots at the edges, an extended dielectric substrate and modified ground. The fabricated antenna prototype is of compact size of 119 × 70 mm². The measurement in anechoic chamber shows a ultrawide operating band from 1.85 to 9.2 GHz and the peak gain of 9.2 dBi. Both simulation and experimental results for the S11 and Gain are presented and compared which come in close agreement. Further, the designed antenna is tested for through wall imaging applications. The emitted signal has been sent in stepped frequency continuous wave (SFCW) mode with 201 frequency points from the VNA and the target under investigation was placed behind the brick wall at a standoff distance. The target location was correctly detected and also the width of the target was further calculated using the delay-sum algorithm.