ABSTRACT 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 diff