Design of X-band low phase noise and low spurious frequency source based on HMC778

For X-band radar velocity measurement system, a low phase noise and low spurious frequency source is designed as the local oscillator of the receiver and the transmitter to improve the SNR and the receiver sensitivity. The design uses phase-locked loop chip HMC778 integrated with VCO from AD company. The reference frequency source is OCXO of low phase noise from KOMA company, and loop filter is active and four-order designed under the Hittite PLL Design software. The power supply part adopts low dropout voltage regulator chip from TI company. The use of power amplifier chip HMC441 can improve the output power, as well as C8051F300 MCU is used for register configuration of the PLL chip. The experimental results show that the phase noise is -92dBc/Hz@10KHz and the spurious suppression is -78dBc in the integer mode, when the phase frequency is 100MHz and the output frequency is 10.6GHz.