Antennas Based on Helipad-Shaped Metamaterials for Applications at 5.8 GHz

In this study, we propose two metamaterials (MTM) inspired ground structures for improving the performance of a rectangular microstrip patch antenna (MPA) while reducing the antenna volume. The dimensions of the presented metamaterial, which has a helipad shape, were optimized to operate the MPA with better performance at 5.8GHz. Simulations showed that including MTM ground can increase the bandwidth from 212MHz to 593MHz and reduce the return losses at the resonant frequency. Moreover, using the proposed MTM has reduced the antemna volume by $64 \%$ (from $1413 \mathrm{~mm}^{3}$ to $508.68 \mathrm{~mm}^{3}$). Finally, the antennas were fabricated, and return losses were measured.