Dual-layer Ebg Structures for Low-profile “bent” Monopole Antennas

We propose in this paper the design, realization and experimental characterization of a low-profile metamaterial “bent” monopole antenna with a total height of 0.027λ0 and a fractional bandwidth of 24.4% around 1.3GHz. The metamaterial (MTM) structure is a dual-layer mushroom-like electromagnetic band gap (DLEBG) conceived and optimized to improve the antenna’s operating bandwidth. Moreover, a “Sabre-Type” antenna composed by two identical “bent” monopole metamaterial antennas placed on both sides of a composite thin slab material has been simulated and realized. The “sabre” antenna provides a vertically polarization and omnidirectional radiation patterns in the elevation plane while its radiation patterns are almost directional in the azimuth plane. A maximum gain of 8.7 dB is obtained by measurement at 1.45 GHz. A remarkable agreement is obtained between the measured and the simulated results.