Reconfigurable Frequency Selective Surfaces With Complementary Reflection and Transmission Responses Using Duality Theorem-Based Elements

Reconfigurable frequency-selective surface (FSS) designs that come with switchable reflection and transmission bands are developed. According to the duality theorem, complementary periodic structures made of similar wire and slot elements shall yield opposite scattering responses. This is facilitated by placing diodes between tips of the proposed #-shaped wire elements. In the reverse-bias state, disconnected elements act as a band-stop-type FSS. By providing a forward bias, connected elements are transformed into a slot array, which generates an inverted passband at the designated resonant frequency. The proposed periodic structure comprises one layer of microstrip line laid on a thin substrate. The #-shaped elements also act as the biasing network for serially connected diodes. Only one bias voltage is needed to control the FSS panel. Range setups and signal processing techniques are devised so that simulated results of infinite FSS can be compared with measured results. By including diode’s equivalent circuits in simulation models, good agreements with prototype measurement results are observed. The complementary reflection and transmission characteristics can be forwarded to advance radome and antenna designs to achieve versatile performance features.