Bandpass frequency selective surface with two sharp sidebands based on shunted quarter‐mode substrate integrated waveguide cavities

Abstract

AbstractA new highly selective bandpass frequency selective surface (FSS) is proposed with sharp sidebands and low profile. The unit element is composed of two shunted quarter‐mode substrate integrated waveguide (QMSIW) cavities with different dimensions and L‐shaped slots etched on both sides of dielectric substrates. Two transmission zeros and three transmission poles are obtained by TM0.5,0.5,0 resonance of cavities, slot resonance, and the coupling between them, which yield a flat passband with steep roll‐off in both sidebands. As unit dimension is miniaturized using quarter‐mode resonance, the FSS presents good angular stability for dual polarization. Simulated results indicate that the passband with insertion loss less than 1 dB covers 8.86–9.57 GHz, while the transitional bandwidth at both sides of the passband is 27 and 25 MHz, respectively. A prototype was fabricated and measured, the experimental results of which verified the design.