Thick frequency selective surfaces

As an additional means of controlling bandwidth, the use of periodic screens in free space with thick metallization was investigated for single-square loop and double-concentric-square loop elements. These loops elements were chosen because the passbands of such screens, with tight lattice spacing, display a remarkable insensitivity to incident polarization and angle of incidence. The effect of thick metallization on passband width was investigated for both transmitted and reflected radiation. All results obtained are from a method of moments solution of the electric field integral equation. For FSS (frequency selective surface) screens with thick metallization, triangular patch basis functions were utilized to represent electric current on the surface of the three-dimensional unit cell structure.<>