Compact SIW Cavity Backed Dual-Polarized Antenna for Torso Imaging

A compact, on-body matched substrate-integrated waveguide (SIW) antenna is designed for torso imaging. The antenna has wideband performance and thus the capability of deep power penetration into the human torso. The design includes two central patches to enable dual polarization, left-hand and right-hand circularly polarization, with an auxiliary patch to improve impedance matching. To minimize back and side radiation and enhance electromagnetic penetration into the torso, the SIW technique is utilized by fencing the substrate edges with metalized vias. Simulation results demonstrate that the antenna operates across a frequency range of 0.72 to 1.70 GHz, achieving an 80% fractional bandwidth with more than 10 dB of return loss. The antenna occupies a compact size of 82×82×8 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>, equivalent to 0.19×0.19×0.01 ${\lambda _0}^3$, where λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> is the wavelength at the lowest operating frequency. The proposed antenna is a proposed candidate for deep torso imaging.