New Pawn-Shaped Dielectric Ring Resonator Loaded Hybrid Monopole Antenna for Improved Ultrawide Bandwidth

A new pawn-shaped dielectric ring resonator (DRR) fed by a simple quarter-wave monopole has been investigated as a new variant of the hybrid monopole-dielectric resonator antenna (DRA). The new geometry, conceived intuitively, significantly improves the impedance bandwidth compared to all earlier versions reported in open literature. S-11 < -10 dB occurring over 5.5-23 GHz has been experimentally demonstrated, indicating over 4: 1 ratio bandwidth, i.e., more than 122% impedance bandwidth around the center of the band. The prototype has been shaped from a dielectric rod with epsilon(r) = 10. Such ultrawideband (UWB) response is caused by multiple resonances occurring by the hybrid monopole-DRA structure. These resonances are identified through several experimental and simulation studies. Uniform monopole-type radiation occurring over the entire bandwidth has been confirmed using measured and simulated results. The peak gain varies from 4 to 6 dBi as a function of frequency. Such useful properties can be successfully used to realize UWB monopole antennas for wireless communications and as wideband electromagnetic interference (EMI) sensors.