Wideband Radiation From an Offset-Fed Split Ring Resonator With Multi-Order Resonances

In this letter, we exhibit the design of an ultrawideband antenna, covering WLAN, WIMAX, and the forthcoming 5G communications band, i.e., from 2.3 to 6.1 GHz, by using the natural oscillating modes of a split ring resonator (SRR). The antenna is composed of a radiating SRR and a coplanar waveguide feeding structure. The excitation of multiple resonances on a single SRR is achieved through an offset feeding technique. In order to improve the impedance bandwidth of the proposed antenna, the width of the SRR's branch is tuned, and several slits are carefully designed on the ground region. Detailed analysis reveals that the proposed antenna can not only radiate in an ultrawideband but also resonate at its lowest mode of a high quality. This peculiar property indicates that the antenna would be a good candidate for incorporating sensing and communication applications.