A Compact and Broadband Metamaterial-Inspired Antenna

In this letter, a small-size metamaterial-inspired antenna with extended bandwidth is presented. Metamaterial structures are extensively used for realization of compact antennas. However, many of these antennas suffer from narrow bandwidth. The presented antenna in this letter is inspired from an epsilon-negative transmission line (ENG TL) with coplanar stripline (CPS) structure. The size of antenna is reduced because of using an ENG TL and operating at its zeroth-order resonance (ZOR) frequency. Antenna bandwidth is also enhanced due to using CPS-like structure. The measured ${-}$ 10-dB impedance bandwidth of this antenna is 12.4%, its size is $0.10\lambda _{0}\times 0.08\lambda _{0}$ , and it is placed over a $0.35\lambda _{0}\times 0.21\lambda _{0}$ ground plane.