Group delay performance of ultra wideband monopole antennas for communication applications

While limited in dimensions, the shape of small ultra wideband (UWB) antennas can significantly impact on the required gain pattern stablity and the inherent impulse spreading throughout the bandwidth. The comparative gain performance of a square monopole and two Bezier-spline shaped monopoles (optimised for low insertion losses on small groundplanes) as portable UWB device antennas solutions are reported. By measuring the transmission group delay for the three geometries in paired combinations, the time-domain spreading due to each individual antenna is solved numerically with a system of equations.