In this research, a novel multi-band reflecting polarization converter is proposed, which uses a single-layered substrate to convert between linear and circular polarization. The top FSS printed on the grounded dielectric spacer comprises an I-shaped metallic patch and an orthogonally connected inductive grid. For the y-polarized EM wave incidence, the design shows linear-cross polarization rotation with a Polarization Conversion Ratio (PCR) of a minimum of 90% from 15.28–17.86 GHz, 39.53–44.46 GHz, 55.46–56.26 GHz with 15.57%, 11.74%, and 1.43% Fractional Bandwidth (FBW). In addition, it also experiences linear-circular conversion with 3 dB minimum Axial Ratio (AR) from 12.06–14.04 GHz, 19.96–36.34 GHz, 47.08–54.74 GHz, and 56.60–57.06 GHz with 15.17%, 58.19%, 15.05%, and 0.81% FBW. Various oblique incidences in the design are studied, and the performance is stable up to 45°. Next, the proposed design is shorted at the end, replicating the diode ON condition mechanically, turning the proposed design into a perfect reflector in the operating range. The unitcell architecture is compact with a periodicity of 0.101 × 0.076 λL2, and overall thickness of 0.064 λL. The authors are certain that the design's small size and excellent angular stability make it ideal for applications calling for reflective type multi-band dual-polarized linear-circular and linear-cross polarization conversion, including reflector response. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.