A Quad-Band Near-Field Antenna Array for a Multistatic Microwave Imaging Chamber

A new quad-band tapered patch transmit–receive antenna array designed for a multistatic microwave imaging cavity system is presented. The reverberating cube-shaped chamber is filled with a matching fluid emulsion and encompasses 64 antenna elements mounted on its sidewalls (16 per panel). Four resonant frequencies that lie in the range of
$\text{0.5--3}$
GHz are achieved. The design procedure is provided based on system constraints and performance requirements that need to be taken into account, which include: first, the near-field nature of the electromagnetic wave in the presence of a shielded chamber and, second, the propagation of waves into the immersion fluid within the imaging domain. The antenna array design was numerically verified, and its prototype was fabricated. Results show a good agreement between measurements and simulations, achieving antenna system performance requirements.