A Miniaturized and Angular Stability Switchable Frequency Selective Surface

This paper proposes a novel switchable Frequency Selective Surface (FSS) design. The designed FSS unit size is only 0.12 λ 0 (where λ 0 represents the wavelength corresponding to the lowest resonant frequency in free space), and its angle stability can reach up to 65°. Meanwhile, it can form stable resonances at the three commonly used frequency bands of 2.4, 3.3, and 5.2 GHz in communication systems. During the switching process, the difference in transmission coefficients between different states exceeds 15 dB, and the insertion loss in the transmission state is stably controlled within the range of 0.92–2.15 dB. Additionally, this design supports independent control of the electromagnetic responses to transverse electric and transverse magnetic polarized incident waves in four modes. After verifying the design feasibility through an equivalent circuit model, a 100 mm × 100 mm FSS prototype was fabricated, and its performance was verified through experimental tests.