Analysis of Miniature Frequency Selective Surfaces Based on Fractal Antenna–Filter–Antenna Arrays

A novel type of miniature bandpass frequency selective surface (FSS) based on fractal antenna-filter-antenna (AFA) array is proposed. The AFA-based FSSs exhibit superior frequency selectivity and have lower profile than conventional FSSs. However, they commonly occupy considerably large unit sizes. Fractal geometries are utilized in this letter to reduce the unit cell of AFA-based FSSs. The iteration order and iteration factors of the utilized fractals including Minkowski island-shaped transmit/receive patches and fractal cross-shaped coupling aperture are analyzed. A prototype of the proposed FSS operated at C-band is fabricated and tested using waveguide measurement setup, and good agreement is obtained between measured and simulated results.