Investigations on high impedance surface size effect to low-profile antenna performance

A low-profile wideband antenna is designed by employing the high impedance surface (HIS) as ground reflector of bowtie antenna. The overall thickness is less than 0.1λ at the lowest operating frequency. The ground size effect to the performance of antenna is investigated. It achieves relatively wide bandwidth of 33.3% for the 6×6 HIS array, and 36.4% for the 4×6 array. The peak directive gains of these two arrays are 5.64 dBi and 5.06 dBi, respectively. It indicates that the ground can be minimized to certain limit while maintaining operational bandwidth, with the cost of gain reduction.