Single‐Layer Polarization Insensitive Frequency Selective Surface Design for Microwave Applications

ABSTRACT This study introduces a compact, single‐layer frequency selective surface (FSS) with multiple frequency bands, designed and simulated using CST Microwave Studio. The FSS is made to resonate at multiple frequencies, achieving significantly lower attenuation levels of −37 dB at 4.4 GHz, making it suitable for medical diagnostic applications, such as breast cancer detection. It also operates with −29 dB at 8.7 GHz (X and C bands, IEEE 802.11a for wireless networks), −13 dB at 13 GHz (low Ku band, commonly used in satellite communications per ITU standards), and −18 dB at 16.5 GHz, which supports microwave thermal therapies for cancer treatment. The FSS is designed on an FR4 substrate with a dielectric constant of 4.4. It has a thickness of 0.8 mm, resulting in a compact unit cell dimension of 0.147λ x 0.147λ. This compact structure makes it appropriate for embedded or space‐limited applications. The design exhibits strong angular stability, maintaining consistent resonant behavior up to a 60° angle of incidence, and demonstrates polarization insensitivity up to 90°, ensuring reliable performance across a range of signal orientations. These characteristics make the FSS highly adaptable to real‐world applications across healthcare, telecommunications, and satellite industries. This study underscores the FSS's broad applicability in advanced microwave technologies, providing a versatile solution for interference suppression and signal control within critical frequency bands.