Compact UWB Monopole Antenna for Automotive Communications

This communication presents a bandwidth-enhanced, compact, monopole antenna with modified ground plane for modern automotive ultra wide-band (UWB) applications. The proposed antenna has hybrid geometry and is constructed using half circular ring and half square ring. The ground plane of the fundamental radiator is curved and defected to improve the VSWR bandwidth. An extended ground stub is added to further enhance the bandwidth to suit the modern automotive requirements. The designed antenna covers 3.1-10.9 GHz frequency spectrum with VSWR <= 2. This antenna can be conveniently placed inside the shark fin housing or it can be printed along with the existing print circuit board (PCB) electronics nullifying the need for dedicated location for in-car communications. Furthermore, a simple two-port multiple input multiple output (MIMO) antenna is constructed and its diversity performance is estimated. The prototype is fabricated and tested for impedance and radiation characteristics.