ULTRABROADBAND DIODE-LIKE ASYMMETRIC TRANSMISSION AND HIGH-EFFICIENCY CROSS-POLARIZATION CONVERSION BASED ON COMPOSITE CHIRAL METAMATERIAL

• Published in: Electromagnetic waves (Cambridge, Mass.) Vol. 160; pp. 89 - 101
• Main Authors: Cheng, Yongzhi, Zhao, Jingcheng, Mao, Xuesong, Gong, Rongzhou
• Format: Journal Article
• Language: English
• Published: Cambridge Electromagnetics Academy 01.01.2017
• Subjects: Applied research; Composite materials; Electric fields; Electric properties; Experiments; Magnetic properties; Polarization (Waves); Propagation; Simulation; Wave propagation
• ISSN: 1559-8985; 1070-4698; 1559-8985
• DOI: 10.2528/PIER17091303

In this paper, a three layer composite chiral metamaterial (CCMM) is proposed to achieve diode-like asymmetric transmission and high-efficiency cross-polarization conversion by 90[degrees] polarization rotation with ultrabroadband range in microwave region, which was verified by simulation and experiment. This CCMM is composed of a disk-split-ring (DSR) structure sandwiched between two twisted sub-wavelength metal grating structures. The simulation agrees well with experiment in principle. The simulation results indicate that the incident y(x)-polarized wave propagation along the -z(+z) direction through the CCMM slab is still linearly polarized wave with high purity, but the polarization direction is rotated by [+ or -] 90[degrees], and the polarization conversion ratio (PCR) is greater than 90% in the frequency range of 4.36-14.91 GHz. In addition, in the above frequency range, the asymmetric transmission coefficient (Alin) and the total transmittance ([T.sub.x]) for x-polarized wave propagation along the -z axis direction are both over 0.8. Finally, the above experiment and simulation results were further verified by the electric field distribution characteristics of the CCMM unit-cell structure. Our design will provide an important reference for the practical applications of the CCMM for polarization manipulation.