Symmetry-breaking manipulation in the design of multifunctional tunable frequency selective surface

The design and characteristics of a PIN diode based tunable Frequency Selective Surface (FSS) is provided. Spatial filtering, polarization filtering and polarization control are all features the FSS exhibits in the considered 2-14 GHz frequency band. The proper symmetries required for the different features are explained and controlled by a holistic approach that includes the effects of the biasing network in the design. Symmetry breaking due to the presence of the biasing network used to bias the active elements are compensated by predistorsion of the initial geometry of the main structure that presents rotational symmetry. The proof of concept presented here allows extending the method to achieve proper design goals.