Multifunctional Metasurface for Linear-to-Linear and Linear-to-Circular Polarization Conversion

This paper presents a compact, multifunctional, passive polarization-converting metasurface (PCM) designed for linear-to-linear polarization (LTLP) and linear-to-circular polarization (LTCP) conversion across distinct, non-overlapping frequency bands. Unlike conventional single-function metasurfaces, the proposed PCM offers two distinct polarization conversion functionalities within a compact single-layer design. The simulated and experimental results show that the PCM performs LTLP conversion in dual frequency bands 5.6 GHz to 6.5 GHz (C-band) and 9.6 GHz to 11.9 GHz (X-band)) with a polarization conversion ratio (PCR) greater than 99% and 95% respectively. Furthermore, the PCM also performs LTCP conversion at 5.4 GHz and from 6.9 GHz to 8.9 GHz (spanning the upper C-band and lower X-band) with an axial ratio (AR) below 3 dB. The design demonstrates minimal reduction in polarization conversion for incident angles from 0° to 30°, which makes it appropriate for practical application where angular variation is inevitable. The broad frequency range and dual-mode polarization conversion, and angular stability of the PCM make it useful for multi-band communication systems, satellite links, polarization-sensitive antennas, and polarimetric radar systems. The design was fabricated on printed circuit board (PCB) and the performance experimentally validated with good similarity between simulated and measured results.