An Electrically Smaller Ultra-Wideband Monopole Antenna for Ground Penetrating Radar Application

In this paper, the design and prototyping of an electrically smaller planar monopole antenna suitable for ultra-wideband radar application is presented. The antenna is
$14.3\ \mathbf{cm} (0.23\lambda_{0}) \times 12.5\ \text{cm}\ (0.2\lambda_{0})$
in its lateral dimension. The antenna geometry is basically a multi-resonant structure consisting of a spiral arm and a wider rectangular arm embedded on the top layer of a low loss substrate. The designed antenna yields almost -10 dB impedance bandwidth from 0.5-6.5 GHz with an average boresight gain of 4.5-7.5 dB by using a reflector. While testing its imaging capabilities, we find that the antenna can accurately image subsurface buried targets.