Characteristic Modes Theory Exploitation for the Design of Transmission-Type Polarization Converters

A novel strategy for the design of a transmission-type polarization converter of linearly polarized (LP) plane waves is proposed. More in detail, a general and straightforward approach based on the exploitation of the characteristic modes analysis (CMA) for identifying the frequency selective surface (FSS) unit cell is described. The excitation of two current modes on the proposed FSS unit cell, both exhibiting a circularly polarized (CP) radiated field, are provided to obtain an efficient polarization rotator. Measurement campaigns confirm the benefits of adopting CMA as well as the remarkable performance.