A Miniaturized Bandpass Frequency Selective Surface Exploiting Three-Dimensional Printing Technique

This letter proposes a miniaturized-element bandpass frequency selective surface using three-dimensional (3-D) printing. The proposed design comprises convoluted metallic patterns on both sides of a dielectric substrate (interdigital capacitors on top, and meander lines on bottom) in an orthogonal arrangement. The novel feature of the structure lies in exploiting 3-D printing technique to selectively extend the dielectric thickness, thereby reducing the resonance frequency. This results in an improved miniaturization characteristic with unit cell dimensions of 0.056λ0 × 0.056λ0, where λ0 is the free-space wavelength corresponding to the resonance frequency 1.05 GHz (having 1.26 dB insertion loss) of the geometry. The topology also demonstrates excellent angular stability under oblique incidence (up to 75° incident angle). We fabricated a 3-D printed prototype, and the measured response was consistent with the simulated result under normal incidence.