A novel transmission type polarizer for K-and Ka-band applications is demonstrated in this work. A thin dielectric substrate is sandwiched between the top and bottom Frequency Selective Surfaces (FSSs) that comprise the polarizer's unitcell. The transmitted wave is circularly polarized for the linearly polarized wave incidence, with a minimum 3dB Axial Ratio (AR) over the frequency from 16.52-39.93 GHz (82.94% relative bandwidth). The performance is stable up to 45° for Transverse Electric (TE) and Transverse Magnetic (TM) incidences. The equivalent circuit model of the polarizer is extracted, and the response agrees with the EM solver results. The possibility to perceive the circular polarization rotation sense is captured by studying electric field patterns at two frequencies. The design is compact with a structural periodicity of 0.088?Lx 0.116?L and thickness of 0.044?L, where ?L is the free-space wavelength corresponds to the lowest frequency of the operating range. The minimum Polarization Extinction Ratio (PER) of 21 dB is observed over the entire operating range. Realtime satellite applications could benefit from the miniaturized volumetric design 0.448(?3L/1000), and the stable angular response of the presented wideband polarizer. © 2022 The Institute of Electronics Information and Communication Engineers (IEICE) of Japan.