A method of frequency synthesis has been present at the XBand with low phase noise based on a highovertone bulk acoustic resonator (HBAR). According to the working principle of HBAR, using a HBAR and sound table filters consist of oscillating loop with low phase noise, which can directly generate Sband signal. X-band signal can be obtained by quadruplicated frequency module. This method serried with SAW filter has raised outofband noise suppression. The phase noise at the frequency of 2.2 GHz reaches -118.9 dBc/Hz@1 kHz, and the phase noise of 8.8 GHz at Xband is -107.4 dBc/Hz@1 kHz after quadruplicated frequency.