The Chinese University of Hong Kong, Star Formation Group (CUHKSFG) is developing ROGer—China’s first submillimeter-wave polarimeter. The instrument integrates two 345 GHz microwave kinetic inductance detector (MKID) arrays with a room-temperature polarization modulation module. This study proposes a cryogenically compatible polarization modulation scheme embedded within the ROGer camera architecture, enabling a compact polarization modulation. The cryogenic module serves as both a functional alternative for ROGer and a technological benchmark for future integrated submillimeter-wave polarimeters requiring compact, low-temperature operation.