DRFM (Digital Radio Frequency Memory) is now widely utilized by modern radar jammers due to its high efficiency in jamming generation. However, its jammer structure is somewhat complex, since the up-conversion and down-conversion processes must be included. This paper proposes a new Synthetic Aperture Radar (SAR) jammer architecture utilizing Direct Radio Frequency Processing (DRFP), wherein both the up-conversion and down-conversion modules can be excluded. DRFP has a very compact hardware structure which employs Direct Digital Synthesizer (DDS), phase shifter and delay lines for jamming modulation.