In this paper an antenna array for imaging applications is presented. A two-step design process is used. In the first step, a wideband printed monopole antenna to be employed as the array element is synthesized by means of a Particle Swarm Optimization (PSO) procedure. The second step is aimed at obtaining an array fulfilling the requirements typical of imaging applications by properly arrange multiple copies of the optimized element on the walls of a cubic dielectric chamber. Simulated and measured data assessing the effectiveness of the proposed array are reported.