The wideband antenna that we developed has a small and thin structure (W 41 /spl times/ H 34 /spl times/ t 0.3 mm); and it is suitable to be installed in small spaces. This antenna has a resonance frequency from 3 GHz to 6 GHz, where VSWR was below 2.0. The radiation pattern is omnidirectional and the average gain curve is almost flat over this frequency range, and the values were around 0 dBi. The group delay is almost flat and its perturbation is within 1 ns over the above frequency range.