An Ultrathin Bandpass Frequency Selective Surface With Miniaturized Element

An ultrathin bandpass frequency selective surface (FSS) with miniaturized unit cell is proposed in this letter. A significant coupling capacitance can be introduced by the large overlapping areas between the two metallic layers of the structure; therefore, the dimension of the unit cell can be decreased to only 0.050λ × 0.050λ, where λ represents the free-space wavelength corresponding to the resonant frequency. The dimension of the proposed FSS can be further miniaturized to 0.034λ × 0.034λ as three more ultrathin patch array layers are added symmetrically. In addition, the proposed FSS exhibits excellent stability for different incident angles and different polarizations. A prototype of the proposed FSS is fabricated and measured, and the measured results agree well with the simulated results.