A Study of Ultrawideband Antennas for Near-Field Imaging

A compact ultrawideband (UWB) antenna has been designed for UWB cancer detection systems. The numerical analysis and experimental characterization of a printed monopole antenna fed by a 50-$\Omega$ coplanar waveguide (CPW) and operating in a lossy coupling medium is presented. A detailed 3D model of the antenna and the biological environment has been constructed and simulated in XFDTD and HFSS. The near-field pattern of the antenna in the proximity of a multilayer human body model and the effect of the human body on the input matching of the antenna are studied. Experimental results show that the return loss is below -9.6 dB from 3.4 GHz to 9.9 GHz.