Resonance frequency formulation for planar rectangular monopole antenna

Ultra-wide band response in planar monopole microstrip antenna is realized due to coupling between fundamental and higher order patch modes. In the reported literature, formulation in resonant length at fundamental and higher order modes of planar monopole patch is not given. In this paper, by studying the surface current distributions for planar monopole rectangular microstrip antenna, a formulation in resonant length at fundamental patch mode for different patch aspect ratio is presented. The frequencies calculated using the same closely agrees with the simulated results. Thus proposed formulations can be used to realize ultra-wide band planar monopole antenna from the desired frequency range.