High-Low-Epsilon Biaxial Anisotropic Lens for Enhanced Gain and Aperture Efficiency of a Linearly Polarized Antenna

This communication presents a high-low-epsilon (HLE) biaxial anisotropic lens for enhancing the gain of a linearly polarized antenna at 28 GHz. The theory and mechanism of gain enhancement using the biaxial anisotropic HLE lens is presented along with the realization of the HLE media using metamaterials (MTMs). First, the gain enhancement is studied using a microstrip patch antenna loaded with the HLE slab, and a peak gain of 13.9 dBi achieved with HLE slab in simulations. This gain enhancement is attributed to the special propagation properties of the waves in biaxial anisotropic media. The HLE media is practically realized using seven MTM layers stacked over each other and then loaded to the patch antenna and the substrate integrated waveguide (SIW) fed aperture coupled patch antenna (ACPA) to verify the gain enhancement. The measurement results confirm realized peak gain of 13.71 and 13.67 dBi for patch and ACPAs, respectively. Both the antennas have an overall height of 0.65λ
₀
, and the proposed technique results in aperture efficiencies greater than 97% and 94% for the two antennas, respectively, at 28 GHz.