A Low-frequency-ratio Frequency-multiplexed Reflective Meta-atom

Frequency-multiplexed metasurfaces are widely used in EM control devices because of their advantages of achieving high efficiency multi-band wavefront control in smaller volume and higher integration. Most frequency-multiplexed metasurfaces usually reduce channel crosstalk by increasing the working spectrum width, which will waste spectrum resources and make the meta-atom not meet the electrical size. To solve this problem, this study proposes a low-frequency-ratio frequency-multiplexed meta-atom with high Q value. By constructing complementary a double C-shaped slotted and a double C-shaped metal resonators with high Q value on a double-layer dielectric substrate, the meta-atom realizes the amplitude of reflection wave approaching 1 and the independent $\boldsymbol{ 2 \pi}$ geometric phase shift at the resonant frequencies $\boldsymbol{f_{1}=9.2}$ GHz and $f_{2}= \boldsymbol{11.2}$ GHz under circular polarization wave excitation. This study presents an effective way to construct frequency-multiplexed metasurface with low frequency ratio.