Modeling of MEMS enabled reconfigurable frequency selective surfaces in aperture of waveguide antenna array

Influence of the reconfigurable frequency selective surface (FSS) with capacitive microelectromechanical (MEMS) switches on characteristics of matching, radiation and scattering of the antenna array (AA) of the open ends of X-band rectangular waveguides is investigated. It is shown that FSS transmits a radiation field of AA in case of switching on MEMS (return losses less than minus 13 dB in a band of 8–12 GHz). The best matching of AA is provided if the FSS is in close proximity to an aperture. Switching off MEMS weakens amplitude of the wave transmitting through FSS on 36 dB at resonance frequency of 9 GHz without varying the form of the radiation pattern; resonance frequency of AA-FSS system depends on distance between the FSS and the AA aperture. Difference of RCS of back scattering of phased AA on working linear polarization in two states of MEMS-switches is able to more than 10–15 dB.