Dual linear/circular polarized plannar antenna with low profile double-layer polarizer of 45º tilted metallic strips for wimax applications

摘要

A low profile double-layer polarizer structure is presented for planar patch antennas to obtain circular polarization in 3.5 GHz WiMAX band (3.4-3.6 GHz≈5.7% bandwidth). Each polarizer layer is composed of 45º tilted metallic strips on a printed circuit. A bandwidth widening is obtained due to a significant reduction of the distance between polarizer and patches. The associated effects from the interaction of the two structures have been studied. A 2x2 array prototype has been implemented and measured, with a 8% average bandwidth in reflection and dual linear/circular polarization.