Stable permittivity and low loss Al2O3 ceramic based metasurface achieves broadband polarization conversion at high temperature

Metasurface devices with EM polarization conversion property and high temperature resistance are promising. In this work, an ultra-thin Al2O3 based ceramic with metasurface structure was designed to realize high-temperature broadband polarization conversion. The key is to utilize the merit of meta-structure and high-temperature resistant ceramics with stable permittivity and low loss tangent. To optimize the target performance, transgenic genetic algorithm (TGA) was introduced to search the optimal parameters of the conversion unit, which achieved over -1dB cross-polarized reflection in a broad range of 11.46 GHz–20.17 GHz with only 1.1 mm thickness under 45° incidence. In the measurement, the prototype, fabricated by screen printing and laser cutting, displayed highly consistent performance to the simulation from room temperature to 500 °C, verifying the practicability of the proposed metasurface.