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

Abstract

A low profile double-layer polarizer structure is presented for planar patch antennas to obtain circular polarization in 3.5GHz WiMAX band (3.4-3.6GHz ≈ 5.7% bandwidth). Each polarizer layer is composed of 45° 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 2 × 2 array prototype has been implemented and measured, with a 8% average bandwidth in reflection and dual linear/circular polarization.