Multi-band metamirrors for linear to circular polarization conversion with wideband and wide-angle performances

摘要

Multi-band operation of the elements of electromagnetic systems can result in merging multiple systems and cost reduction. A challenge for multi-band operation is the circular polarization which is frequently a requirement for these systems. However, circular polarization can be obtained from linearly polarized waves using transmissionmode or reflection-mode linear to circular polarization converters. Therefore, advanced multi-band reflection-mode linear to circular polarization converters are proposed in this paper. Two versions of the polarizers are designed with different design methodologies. The first polarization converter has 3 dB axial ratio bandwidths of 29.3, 21.8, and 7.6% on 2, 8, and 12 GHz with 15 degrees permitted incident angle difference. The second polarization converter with incident angle range of 25 degrees(theta(min) = 23 degrees and theta(max) = 48 degrees) has 17.8, 10, and 22.5% bandwidths on 2, 5.5, and 8 GHz, respectively. In addition, the bandwidths can be improved to 32.1, 28.3, and 26.5% by reducing the incident angle range to 10 degrees with theta(min) = 30 degrees and theta(max) = 40 degrees. Finally, a prototype of the second polarization converter is fabricated and simulations are met by measurement results.