Modeling of Circularly Polarized Stacked Patch Antenna

In this paper, a coupled-resonator circuit model is proposed for a circularly polarized (CP) stacked patch antenna. The x- and y-polarized far-field radiations are regarded as two virtual output ports while the degenerate resonant modes of both the lower and upper patches are considered. Then, a three-port fourth-order filtering network is constructed. The coupling matrix can be established, with the definite physical meanings for all the elements, to predict the performance of the CP stacked patch antenna, including the port reflection, antenna efficiency and axial ratio. The modeling method is verified numerically. It is expected that this method will provide an efficient way for the design and optimization of CP stacked patch antennas.