Design of Multichannel Triple-Band Reflective Metasurfaces With Large Frequency Ratio Supporting Spin Decoupling and Full-Polarization Decoupling

This article presents multichannel triple-band reflective metasurfaces (MSs) with a large frequency ratio, which support spin decoupling and full-polarization decoupling. First, by introducing the frequency-selective surface (FSS) and considering the mutual influence between the meta-atoms operating at different frequencies, the triple-band operation from microwave band to millimeter-wave (mmW) band can be realized. Next, by adopting the spin-decoupled strategy, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 3$ </tex-math></inline-formula> bit and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 2$ </tex-math></inline-formula> bit dual circularly polarized (CP) phase coding strategies for C and K/Ka unit cells are designed, respectively. Meanwhile, the independent full-polarized operation could also be realized from the spin-decoupled strategy. Finally, two types of MSs with a radius of 147.9 mm are designed, fabricated, and measured. Both the simulated and measured results confirm the feasibility of the proposed MSs. The first type of MS, illuminated by CP feed sources, generates well-performed left-handed CP (LHCP) and right-handed CP (RHCP) beams independently at C-, K-, and Ka-bands. The second type of MS, illuminated by linearly polarized (LP) feed sources, generates well-performed x-polarized, y-polarized, LHCP, and RHCP beams independently at C-, K-, and Ka-bands.