Gain enhancement and miniaturization of microstrip antennas using MTM superstrates

This paper introduces two metamaterial (MTM) unit cells with negative permittivity and permeability. Both unit cells are incorporated with three conventional rectangular patch antennas that resonate at frequencies 9.64 GHz, 7.2 GHz, and 17.7 GHz, respectively. To achieve the best results, the dimensions of the structures have been optimized. The simulation results such as return loss, gain, half power beamwidth (HPBW) and radiation patterns have been analyzed. The gain of the antennas which resonate at frequencies 9.64GH and 7.2GHz, increased up to 2.2 dB. Incorporation of the second superstrate structure with the last antenna brings a size reduction about 43% for this antenna. For both superstrate structures, by increasing the number of MTM layers above the antenna, the HPBW is decreased and antenna became more directive. The second structure cause HPBW decrease more, because we omitted some edges from the first unit cell´s structure.