W-band Phase-locked Multiplier Source Research

W-band is an important frequency band in military field. Typical W-band systemapplications include radar, guidance, communication, radiometry, instrumentation, etc.However, development efforts in these fields are hindered by the difficulty in findingsolid-state frequency source with sufficient power, low phase noise and large bandwidthfor general use in variety of projects. Multiplier chain pumped by a phase lockedmicrowave frequency synthesizer might be the best way of generating mm-waves,because multiplier not only extends the frequency range, but also keeps the merits ofmicrowave synthesizer, such as low phase noise, narrow frequency step, multi-outputfrequency points, etc. Research on the W-band multiplied phase locked frequencysynthesizer is carried out in this thesis.First, the phase noise model of the phased locked loop and a mathematical analysismodel of the degradation in phase noise-to-carrier ratio of various components (passiveelements with loss (filters, attenuators, etc.), linear amplifiers, and frequency translationdevices, such as multipliers and mixers.) are analyzed. This analysis technique is usefulin predicting the degradation to phase noise caused by these components. Based onthese theories, scheme of the project is proposed and analyzed. One of the crucialtechniques (low phase noises, low spurious level, small size, etc.) is resolved whenrealizing the low phase noise microwave frequency synthesizer unit, which can ensurethe low phase noise characteristic in w-band.Secondly, mm-wave times-12 multiplier chain (the most difficult problem of theproject) is realized in section four. The multiplier chain consists of a Ka-band activequadrupler and a balanced W-band passive tripler. The Ka-band active quadrupler isrealized by commercial MMIC chips for simplifying the design and improving thereliability. Then, the balanced multiplication theory is studied in section 4.2. The keycomponent (W-band passive tripler) of the project is designed by using the way ofcombining "circuit" analysis and "E-M field" analysis to ensure the yielding. TheW-band passive tripler in this paper has a good performance, the output power andconversion loss are far better than the HMM3W tripler of Terabeam; the output power is higher than the standard MUT-10 tripler of Millitech.Thirdly, the system measurements and tests are carried out; a mathematical modelof the degradation in phase noise-to-carrier ratio of harmonic mixer is established toanalyze the measured phase noise. Measurement and analysis show that the W-bandmultiplied phase locked frequency synthesizer covers 92.4GHz～95.6GHz with aminimal step of 40MHz, low phase noise (better than -75dBc/Hz@10kHz,-74dBc/Hz@100kHz, -95dBc/Hz@1MHz in the whole output band), sufficient power(-5.7dBm to -3.6dBm), and a size of 98×95×27mm~3.This W-band multiplied frequency synthesizer has advantages in frequency band,low phase noise, power consuming, and system size when compared to the Gunnphase-locked signal source.