Design Of Low Phase Noise Microwave Oscillator

To meet the needs of microwave and millimeter wave test equipment and systems, and toachieve the development trend of miniaturization and modular instruments, especially to theup and down frequency conversion device operating at Ku and Ka band and microwavedevices and PXI modular test instruments and systems requirements, a miniaturized lowphase noise microwave oscillators and the low phase noise microwave oscillator that based onthe PXI bus are designed.Firstly, the design technologies and programs of microwave oscillator are introduced andthe advantages and disadvantages of each program are compared. The indicators ofmicrowave oscillator to the up and down frequency conversion device operating at Ku and Kaband is analyzed, and the single phase loop-locked frequency synthesis technology is chose asthe key technical solutions.Secondly, based on the calculation method of the phase noise of the phase loop-locked,the phase noise of the phase loop-locked of the different phase frequency, phase detectorsensitivity, loop bandwidth are calculated, and the most important factors affecting the phasenoise of the phase loop-locked is analyzed. According to the analysis results, the reasonableoptimum parameters of the frequency synthesizer circuit and the software parameters of phaseloop-locked chip are chose that can implement low phase noise, so the key technology of lowphase noise microwave oscillator is solved.Thirdly, microwave oscillator circuit is designed based on monolithic integrated PLLchip HMC704LP4E and VCO chip V940ME24-LF,and miniaturized microwave oscillator isbetter realized.The printed circuit board of microwave oscillator is designed by circuit designsoftware Altium Designer10.0. Physical indicators are tested by the CETC41’s testinstruments. The test results show that the measurement and calculation of phase noiseindexes agreed well, which come up to the corresponding design specifications of themicrowave oscillator. The design method is effectiveness and feasibility, and it can meet thepractical engineering application.Lastly, the indexes of the PXI bus microwave oscillator is analyzed, and the mixer phaseloop-locked frequency synthesis is chose as the key technical solutions. The PXI bus interfaceand the frequency synthesizers are designed. At the same time, the process of the circuit design is introduced and the different N frequency divider of the output phase noise of themicrowave oscillator are calculated. By comparing the calculation results, the best parameterof the mixer PLL circuit is set to achieve low phase noise indicators. On this basis, thesoftware configuration of the PXI bus and the configuration parameters of phase loop-lockedchip are designed. The printed circuit board of microwave oscillator is designed by circuitdesign software Altium Designer10.0. Physical indicators are tested.The test results showthat the measurement and calculation of phase noise indexes agreed well, which come up tothe corresponding design specifications of the microwave oscillator, and it can meet the autotest system application which is based on PXI bus.