A Crescent-Shaped Multiband Planar Monopole Antenna for Mobile Wireless Applications

A planar multiband monopole antenna is presented for mobile wireless applications. The antenna is constructed from a crescent-shaped radiator patch, microstrip feed line, and defected ground structure (DGS). Theoretical and experimental characteristics are presented for this antenna, which achieves an impedance bandwidth of 58.3% (over 1.7-3.1 GHz), at a reflection coefficient |S11| < -10 dB and has an average gain of 1.75 dBi.