Equivalent-circuit models for frequency-selective surfaces at oblique angles of incidence

TLDR

Equivalent‑circuit modelling is a valuable tool for designing printed frequency‑selective surfaces, and the use of immittance correction terms is highlighted as important. The authors derive a correction term that enables transmission responses to be modeled at oblique angles and validate models for gridded‑square and double‑square arrays against experimental data for normal and oblique TE and TM incidence. The models show good agreement with measurements for incidence angles up to 45° in the principal planes.

Abstract

The equivalent-circuit-modelling technique is useful for designing printed frequency-selective surfaces. A correction term is derived which enables transmission responses to be modelled at oblique angles of incidence. Models derived for arrays of gridded-square and double-square elements are compared with experimental results for plane waves at normal incidence and at oblique angles for TE- and TM-incidence. Good agreement is obtained for angles of incidence up to 45° in the principle planes. The importance of using the immittance correction terms in the models is also discussed.