Near-Reflectionless Polarization Control Based on Cascaded Metasurfaces

Wireless powering and communication for implanted medical devices have been an attractive topic in recent years. Avoiding polarization isolation and reducing reflection at the interface between air and body are two important solutions to promote the performance of wireless powering and communication for implanted medical devices. In this paper, we proposed a three-layer cascaded metasurface, forming anisotropic responses that provide both near-reflectionless wireless transmission from external into the body and polarization conversion at 28 GHz. Wave-matrix analysis is used to obtain values of the sheet admittances. Then, patterned metallic claddings are used to realize the sheet admittances. Finally, we validate the solution of wave-matrix analysis through numerical simulation. The proposed metasurface realized an axial ratio of 0.3171 dB with an efficiency up to $\mathbf{9 6. 4 \%}$ at 28 GHz. With the ability to reduce the reflection between two different media and control polarization, the metasurface shows great application prospects in medical communication, sensing, and powering.