Ultra wideband coplanar waveguide fed spiral antenna for humanitarian demining

Abstract

-A cavity backed coplanar waveguide to coplanar strip fed logarithmic uniplanar spiral antenna, which covers a 9 to 1 bandwidth with a return loss better than 10 dB from 0.4 to 3.8 GHz is presented. A wideband balun covering the frequency range of the antenna was developed.The constructed spiral antenna is very useful in a stepped frequency ground penetrating radar for humanitarian demining due to the very wide bandwidth, relatively small size, and being uniplanar. Successful detection of a small 5.4 cm non-metallic AP-mines in a pseudo minefield are presented.

Inkjet printed ultra wideband spiral antenna using integrated balun on liquid crystal polymer (LCP)

“…Equiangular spirals have been of the first antennas to be used as UWB antennas because they are selfcomplementary [2] and therefore their input impedance is frequency independent, however they generally require a bulky external balun which makes the antenna big and high profile [3]. Instead of the conventional central feeding, it is possible to feed a spiral externally so the balun can be integrated into the antenna in order to overcome the need of a bulky balun [4].…”