Research of High Performance Frequency Synthesizer for X-Band LFMCW Radar Application

This paper describes a low phase noise and low spurious frequency synthesizer based on DDS (Direct Digital Synthesis)-PLL (Phase-Locked Loop)-MIX (Mixer) architecture. The architecture combines the advantages of both DDS and PLL, In order to achieve a good performance at phase noise and spurious, a mixer has been introduced. According to this structure, an excellent performance X-Band LFMCW (9.6GHz-9.9GHz) frequency synthesizer with low phase noise , low spurious in narrow band SFDR , linearity 8.76E-S is developed. Using this architecture, the phase noise of X band signal can be better than - 12SdBc/Hz@10KHz.