Dual-Band With Dual-Linear Polarization Frequency Selective Surface Utilizing Aperture Coupled Technique

This article investigates the design and development of a frequency selective surface (FSS) that achieves a dual-passband and dual-linear polarization. It consists of two independent corner-truncated square patch resonators to examine dual-passband responses, and a cross-coupled aperture is used to produce two independent linear polarizations (vertical and horizontal) for both passbands. The patch resonators are arranged back-to-back, separated by a metallic aperture-coupled layer located at the middle. The two passband responses correspond to Sub-section I (SS-I) and Sub-section II (SS-II). The first passband arises when a crossed aperture is etched into the middle metallic layer beneath the patch resonator in SS-I, while the second passband is achieved under similar conditions in SS-II. The incidence wave orientation to the designed FSS is either a vertically/horizontally/combination of both polarized waves. The FSS is designed, a prototype is fabricated, and its simulation results are compared with and validated by the measured results. The results are satisfactory and carry two passbands and dual linear polarization simultaneously with a low frequency band ratio and a maximum insertion loss of about 1.2 dB, which also indicates that the frequency performances of both designed FSSs are stable under different incident polarizations and angles (up to $30<^>{0}$ ). In addition, the proposed design is useful to improve the polarization diversity and enhance the frequency selectivity (allow or block the specific frequency) for dual passband by incorporating polarization conversion in various microwave applications.