Standardized Design Technique of PPS-Based 90° Linear Polarization Converters by Means of Coupler Theory

Abstract

A standardized design method of planar periodic structure (PPS)-based 90° linear polarization (LP) converters is presented. This procedure enables standardized designs centered at an arbitrary frequency in either reflection or transmission at normal incidence, which may be achieved with no computational cost and can be used to obtain suitable designs at oblique incidence. It uses both Foster’s equivalent circuits and the classic coupler synthesis, which allow the number of layers, the values of the lumped elements, and the lengths and impedances of the spacers needed to fulfill any prescribed requirements in terms of XP, insertion losses, and bandwidth to be known. The selection of the PPS scatterer that provides the appropriate values of the circuit elements is also studied. Several designs are presented to validate the proposed method, one of which converts a vertical polarization into the horizontal in transmission, exhibiting simulated results of XP < −30 dB, insertion losses better than 0.1 dB, and bandwidth that improves other rotators in the state of the art for the same number of layers. The designed device has been manufactured and experimentally tested, and the results validate the methodology.