Differential antenna feeding system for short range UWB radar

The use of a differential or hi-polar antenna configuration is discussed for Ultra-Widehand Ground Penetrating Radar measurements. The system comprises a central fed TEM horn antenna and two similar receive antennas placed symmetrically on either side. The difference signal from the two receive antennas is used to realize a differential footprint on the ground, and to reduce both antenna coupling and clutter return from a homogenous ground interface. The success of such a system depends in no small measure on symmetry being maintained, and a simple yet effective "loop" balun configuration is introduced to feed the TEM horn.