A new reconfigurable frequency selective surface design with wide tuning range

A new reconfigurable frequency selective surface (RFSS) design is introduced. The structure comprises a planar array of vertical dipoles which are pinned to the substrate at the center. The dipoles in each row are connected together with two long horizontal stripes at the top and the bottom so that by moving connecting stripes forward and backward horizontally, dipoles can rotate around their center. By controlling the movement of connecting stripes, the resonant frequency of the structure can be tuned. A very wide tuning range (more than 140% fractional bandwidth), with a negligible loss of performance, is obtained in filtering response. In order to attain physical insight of the performance of the structure we will first consider the equivalent circuit of the unit cells to obtain resonant frequencies and then simulate the structure using CST Microwave Studio. A good agreement between the results is observed. Moreover some preliminary experimental results provided to allow justification of the validity of our novel design. These features make the proposed structure promising for designing smart surfaces and filters to null out interference and also for implementing as an efficient switching device. The design can be scaled to find applications in different ranges of frequencies.