Design and Realization of an S-band High Performance Frequency Synthesizer for Radar System

In this paper, a kind of S-band high performance frequency synthesizer is presented, which also provides two independent high-quality point frequency. Based on comb spectrum signal source, the S-band frequency can be obtained by mixing frequency signals from DDS and switchable filter bank. With adoption of the FPGA control circuits, this frequency synthesizer can easily realize fast sweep mode which's scanning step is less than or equal to 1MHz. Besides, it has other advantages such as controllable waveform, very low phase noise and high spurious suppression. The measured results show that the spurious rejection is better than 80dB within most frequency points, 75dB within the whole band, and the frequency hopping time is as low as 248 ns, that can be widely used in radar communication and electronic countermeasure system.