Polarization converters based on metamaterial have broad application in imaging, sensing and communication from microwave to optical frequency. However, its performance is limited by single function and narrowband. In this paper, a new type of polarization converter based on square loop shaped metamaterial has been presented. It works in the reflection mode to achieve broadband polarization conversion for both circular and x/y linear polarization waves. The incident linearly polarized wave will be converted to its cross-polarized state with a polarization conversion ratio (PCR) lager than 0.9 in two distinct broad frequency ranges; on the other hand, circularly polarized wave will be reflected to its co-polarized state efficiently in the same spectrum regimes. Good agreements have been observed for both simulation and measurement results. This work offers a further step in developing high performance multi-function microwave or optical devices.
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