Analysis of stacked rectangular patch antennas with nonalignedpatches or unequal patch sizes

Using the spectral domain technique, changes in the characteristics of electromagnetically coupled stacked rectangular patch antennas due to variations in the alignment of patches and patch sizes are investigated. Some of the observations can be used in the design of these antennas in order to equalize the input impedances at the resonances, shift the resonant frequencies, broaden the bandwidth, and estimate changes in the radiation patterns. It is specifically shown that a displacement in the top patch in the direction of resonance can broaden the beamwidth in the E-plane at the upper resonance at the expense of some distortion in the radiation pattern