Slot bowtie antenna for dual-frequency operation

A slot bowtie, cut in a conducting plate on a dielectric substrate, is backed by a conducting reflector, where the distance between the bowtie and the reflector is chosen to be small to make a low-profile antenna. The antenna is designed for dual-frequency operation at 2.45 and 5.2 GHz. It is found that operation at 2.45 GHz depends on the length of the bowtie, while operation at 5.2 GHz depends on the location of the feed point. Frequency bandwidths of 4.8 and 6.2% (for a VSWR = 2 criterion) are obtained around 2.45 and 5.2 GHz, respectively. The radiation is unidirectional and the cross-polarisation component is small.