Wideband slot antennas for wireless communications

The paper presents a wideband antenna design, referred to as the planar volcano-smoke slot antenna (PVSA), useful for wideband wireless communication applications. The antenna is a planar slot - with an appearance reminiscent of a volcanic crater and a puff of smoke - and is fed by a coplanar waveguide (CPW) to achieve the wide bandwidth. A coax-to-CPW transition, which is crucial for achieving wide bandwidth performance, is modelled and introduced into the antenna, and the impedance, pattern bandwidths and radiation patterns of the antenna are investigated. It is demonstrated that the PVSA has an impedance bandwidth between 0.8 and 6.7 GHz (for a VSWR <2.3) and a pattern bandwidth ranging from 0.8 GHz to 2.0 GHz for the radiation in the upper hemisphere. Finally, an absorber-backed PVSA is designed to suppress the radiation along the side- and back-directions. A front/back (F/B) ratio of better than 15dB has been achieved over the band with an absorbing enclosure backed by a PEC plate.