Metamaterial Slabs Covered UWB Antipodal Vivaldi Antenna

Abstract

An ultrawideband metamaterial slab (meta-slab) covered antipodal Vivaldi antenna (AVA) with high-gain and stable radiation patterns is presented. The meta-slab exploiting the dispersive nature of metamaterial exhibits an effective permittivity function higher than the one of the bare dielectric slabs. The high-permittivity meta-slab sucks energy from the tapered slot and the flare termination of the Vivaldi antenna and transmits the energy to the endfire direction. Both the original antenna and proposed antenna are simulated, fabricated, and tested. The simulated results show good agreement with the measured results. In the measured range of 3.68-43.5 GHz, S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> of both antennas are less than -10 dB. Measured far-field results show the proposed antenna provides boresight gain >10 dBi over the 10-20 GHz, >15 dBi over the 20-32 GHz, and >17 dBi over the 32-40 GHz. It also exhibits stable radiation patterns with narrower beamwidth and lower sidelobe level in both the E- and H-plane compared to the AVA.