A Single-Layer Miniaturized Patch Antenna Based on Coupled Microstrips

A new method to miniaturize patch antennas is presented by using coupled microstrip patches. A design example is given at 8.45 GHz. The resultant patch antenna has an electrical size of 0.146 × 0.146 × 0.04
λ
₀
³
, which is about 60% area reduction with respect to a conventional patch antenna. The miniaturized patch antenna shows similar broadside radiation patterns and a lower cross-polarization level as compared with the conventional one. It exhibits a realized gain of 5.4 dBi with the half-power beamwidths of 107° in the E-plane and 87° in the H-plane, respectively. Both simulated and measured results demonstrate that the miniaturized patch antenna exhibits excellent impedance and radiation characteristics and is a promising candidate for highly integrated wireless systems.