An Ultra Wideband Reflective Polarization Conversion Surface for Near-Field Sensing

To enhance the quality of near-field frequency diversity imaging, we propose a novel reflective polarization converter consisting of split-ring resonators and a cross pattern, with a fractional bandwidth of 101.63%. Our proposed converter achieves a polarization conversion rate (PCR) exceeding 88% within the frequency range of 9.8-30.05 GHz. The converter efficiently facilitates the conversion between x-polarized and y-polarized waves, rendering it highly suitable for near-field microwave imaging applications. An example demonstrating the perception of metallic object is given, using the proposed polarization converter.