Miniaturised bandstop frequency selective surface based on quasi‐lumped inductor and capacitor

Abstract

A novel frequency selective surface (FSS) based on quasi-lumped inductor and capacitor is proposed to miniaturise FSS unit cell size. The quasi-lumped inductor and capacitor, implemented by meander line and parallel-plate capacitor, respectively, are connected in series to achieve a bandstop filtering response. This FSS provides the advantages of small unit cell size, independent control of the filtering response for different polarisations, and easy optimal design of desired resonant frequency and bandwidth. To validate the proposed design concept, a bandstop FSS operating at 2.42 GHz was designed, fabricated, and measured. Its unit cell size is only (λ 0/28) × (λ 0/28), where λ 0 refers to the resonant wavelength in free space. Both the simulated and measured results exhibit stable filtering performance under different polarisations and incident angles (up to 60°).