Gain enhancement evaluation in superstrate-loaded planar antennas

An analytical method is proposed for the estimation of gain enhancement in superstrate-loaded microstrip patch antenna, when its dielectric substrate and superstrate are replaced by air. The validity of the proposed analytical model is verified over different physical dimensions of the antenna. Analysis is carried on a rectangular microstrip patch antenna and a hexagonal microstrip patch with various combinations of air and dielectric materials as substrate and superstrates. Rectangular microstrip patch antenna etched on dielectric substrate and loaded with superstrate resonates at 1.67GHz and the same antenna resonates at 2.97GHz when both the dielectrics are replaced with air. Similarly the rectangular microstrip patch resonates at 2.41 GHz when only the substrate is replaced with air and resonates at 1.8 GHz when the superstrate is replaced with air. The hexagonal microstrip patch antenna resonates at 3.9GHz when it is etched on dielectric substrate and loaded with dielectric superstrate. By replacing both dielectric substrate and superstrate with air the hexagonal microstrip patch antenna resonates at 8.3GHz. Similarly, when the substrate is alone replaced with air the hexagonal microstrip patch antenna resonates at 6.7GHz. The hexagonal microstrip patch antenna resonates at 4.3GHz when the superstrate is alone replaced with air. The antenna´s performance evaluation is done at their respective resonant frequencies. Alternatively Finite element method based 3D simulator is utilized to calculate the gain enhancement. Both the theoretical and simulation results are comparable with the proposed analytical model.