High-temperature broadband reflection reduction: design, fabrication, and characterization

We report the design, fabrication, and measurement of a refractory metamaterial with a broadband reflection reduction insensitive to temperature. This is achieved based on a polarization conversion, which demonstrates a significant bandwidth expansion due to the three electromagnetic resonances generated in a simple cut-wire unit. The unit cell can effectively convert linearly polarized waves into cross-polarized waves in the frequency band of 4.3 GHz to 7.3 GHz, with the polarization conversion ratio (PCR) above 90%. After arranging the polarization conversion units in chessboard layout with 0/1 form, a low specular reflection below -10dB from 4.3 GHz to 7.3 GHz is obtained. The broadband reflection reduction has been experimentally validated in a wide temperature range from room temperature to 500 degrees C. It is believed that these results may provide a new route to achieve broadband reflection reduction at a wide temperature range and are promising for many applications. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.