A compact stacked quarter-wave circularly polarized patch antenna

Two miniaturization techniques, the use of high dielectric substrate and vertical shorting walls, are combined in this design to implement a compact circularly polarized patch antenna for use in low frequency (400-500 MHz) applications. Two different high dielectric substrates are utilized to achieve a compact footprint with a stacked structure. Vertical shorting walls are incorporated into the structure to provide quarter-wave operation in both orthogonal directions. The coaxial feed position on the diagonal provides the rotation of the fields in a circular manner from the upper to lower layer.