A Polarization Independent Frequency Selective Surface Based on the Matryoshka Geometry

Frequency selective surfaces, FSS, are well known structures with applications from microwave to terahertz. One of the most adjustable parameters in the design of the FSS is the geometry of the basic cell element. Recently, the Matryoshka geometry was introduced, with very interesting characteristics, highlighting the miniaturization. However, this geometry was polarization dependent. To overcome this drawback, in this paper a polarization independent FSS, based on the Matryoshka geometry, is described, keeping the miniaturization features. Initial project equations are proposed, achieving very good results. Three FSS were fabricated and characterized, verifying a good agreement between numerical and experimental results. When compared to the circular ring geometry, a reduction in the resonant frequency up to 44% was attained. The stability of the resonant frequency for three different incident angles, from 0° to 45°, confirms the polarization independence, extending the potential applications of the Matryoshka geometry.

I. Introduction

Frequency selective surfaces, FSS, have been widely used in in telecommunications systems. Initially, FSS were employed in radomes, absorbers and dual band antennas sub-reflectors systems [1], [2]. More recently the FSS principles have been used in reconfigurable antennas [3], sensors [4], thermal and communication efficiency in smart buildings [5] etc. Essentially, the FSS consist of basic elements etched on a dielectric substrate, arranged in a planar periodic structure, providing filtering properties. The FSS frequency response depends on the polarization of the incident wave, the substrate properties, the geometry and periodicity of the basic cell elements [1], [2], Fig. 1. Fig. 1.

FSS geometry and parameters that affect the FSS frequency response.