A Circuit-Driven Design Methodology for a Circular Polarizer Based on Modified Jerusalem Cross Grids

This paper presents an accelerated methodology to design a circular polarizer based on modified Jerusalem cross unit cells. The proposed three-layer planar polarizer features a high transparency to both TE and TM polarized fields while providing a quadrature phase difference between them, as required for the generation of circularly polarized fields. The structure is designed employing a circuit-driven approach in which two independent equivalent circuits describe the behavior of TE and TM modes through the polarizer. Featuring a unit cell volume of 0.17λ0× 0.17λ0× 0.21λ0, the polarizer offers axial ratios of less than 3 and 1 dB over 20% and 7% bandwidths around 20 GHz, respectively, with an insertion loss less than 0.4 dB. Full-wave numerical simulations and experimental measurements verify not only the performance of the proposed polarizer but also the accuracy of the circuit-driven approach and its ability as a design tool.