Bandwidth-Enhanced Compact ENG Metamaterial Antenna for WLAN and X-Band Applications

In this paper, a compact and bandwidth-enhanced metamaterial antenna is presented. The proposed antenna is designed by embedding a two-unit cell epsilon-negative transmission line (ENG-TL) on an FR4 epoxy substrate with thickness of1.6 mm. A coplanar waveguide (CPW) feed is used as the hosting transmission line to facilitate a via-less design. The bandwidth is improved by merging the zeroth-order resonance (ZOR) and first positive-order resonance (FPOR) of the ENG-TL with feed patch’s resonance with proper frequency spacing. The antenna miniaturization is achieved through the ZOR excited in the ENG-TL. The CPW feed allows very less fields to be confined within the dielectric substrate and facilitates more fields to be radiated out in air which improves the radiation efficiency. The simulated results show -10dB fractional bandwidth of 81.40% (5.15-12.22 GHz), peak radiation efficiency of 86.80% and a peak realized gain of 2.23 dB. The proposed antenna has a compact footprint of 0.23$\lambda_{0}$x0.25kx0.02k at 5.15 GHz. It can be used for WLAN (5.15-5.85 GHz) and X-band (8-12 GHz) applications.