Study On Ka-band Frequency Synthesizer With Low Phase Noise

With the rapid development of the fifth generation mobile communication(5G),automotive autopilot,medical detection and many other fields,millimeter wave has attracted much attention because of its large spectrum resources.The primary problem is the high-performance frequency signal source,which needs the support of high stability,low phase noise and broadband millimeter wave frequency synthesizer.After analyzing the working principle of the components of the phase-locked loop and the transmission characteristics of the loop system,the Ka-band frequency source design research was carried out in this thesis,including the procedures of forming a system scheme,carrying out system design and development,and completing the performance evaluation test.The followings are results:(1)The PLL circuit unit has been successfully developed.ADF5355 chip is used as the main chip of PLL to simulate and optimize its transmission characteristics and phase noise.According to the simulation results,the schematic diagram of PLL circuit is drawn.Rogers RO4350 board is used to design the impedance matching of PLL circuit based on microstrip line theory.PCB layout is drawn and printed circuit board is processed.The normal operation of the phase-locked loop requires configuration of its internal registers,and the control of the phase-locked loop circuit is completed by the microcontroller CY7C68013 A chip.The test results show that the PLL can achieve an output frequency range from 0.054 GHz to 14 GHz with a frequency step of 1.2MHz,a phase noise of-132.84dBc/Hz@1MHz at 1.8GHz and-120.72dBc/Hz@1MHz at 12 GHz.(2)A frequency multiplier has been developed successfully.Using HMC561 chip,a frequency multiplier which can achieve frequencies from 8GHz to 21 GHz is designed,and the effect of frequency multiplier is good,and the multiplier has a gain effect with a maximum gain of 6dB within 11GHz-15 GHz.(3)Ka band frequency synthesizer system is built by cascading phase-locked loop circuit,power amplifier and HMC578 frequency multiplier module.The test results show that the system can achieve a stable output frequency ranging from 24 GHz to 28 GHz,with a frequency stability of 0.6pmm,a frequency stepping of 2.4MHz and an output power of more than 0dBm.The spurious suppression is better than-50 dBc,and the phase noise is-113.90dBc/Hz@1MHz at 27 GHz.(4)A millimeter-wave transceiver module was built to test the designed frequency synthesizer as the signal source of the transmitting module.The results show that the signals generated by the millimeter wave frequency synthesizer can be accurately received at the receiving end at different frequency points,and the frequency synthesizer can provide a signal source for the system.