An Ultrawideband Microstrip Dual-Ring Antenna for Millimeter-Wave Applications

A new ultrawideband (UWB) dual-ring antenna is presented in this letter. Two ring resonators are combined to provide a broadband operation bandwidth of 33.2%, from 31 to 42.8 GHz, with an average gain of 4.5 dBi. The radiation patterns over the whole operation band are stable. The antenna is printed on R/T Duroid 5880 substrate with epsivr = 2.2 and a thickness of 1.3 mm. The newly developed UWB antenna is useful for commercial and military mobile communications, and can be easily redesigned for the applications of microwave or higher millimeter-wave bands.