| At present, the diversity of radio application, which caused to strains on frequencyresource and brought into rapid development of novel millimeter-wave radar andwireless communication, has new requirements to millimeter-wave systems, such asbetter electrical performance and higher integration. Millimeter-wave planar oscillator isthe key component of the millimeter-wave planar integrated systems, and itsperformance directly affects the performance of an entire millimeter-wave integratedsystem and the function realization. In millimeter-wave frequency band, phase-noise isone of key indicators. Therefore, it is very significant to carry out research on highperformance and low phase-noise millimeter-wave planar oscillators. Based on thenovel planar transmission line structure--substrate integrated waveguide (SIW), thisdissertation studies deeply the design and application of millimeter-wave lowphase-noise planar oscillators. The main research works are summarized as follow.(1) The dissertation systematically introduces the SIW structure, and summarizesits basic theory, electrical performance and design method.(2) In this dissertation, the analysis method and design theory of oscillator aresystematically presented. The phase-noise performance of oscillator circuits and therealization methods of low phase-noise oscillators are also discussed detailedly.(3) Based on the electromagnetic simulation softwares, the basic characteristics ofSIW resonator are discussed in detail, which include resonant frequency, quality factorand energy coupling structures. And then, based on the Negative-Resistance Method, adesign procedure for low phase-noise millimeter-wave planar oscillator is presented inthis dissertation. A novel mechanically tuning SIW planar resonator is used in W-bandoscillator circuit, and the effects of SIW planar resonator to millimeter-wave planaroscillator are also analyzed in detail. Experiment results validate that this resonatorstructure can be used to design the low phase-noise millimeter-wave planar oscillator.(4) According to the urgent demands for millimeter-wave planar systems to thehigh stability and low phase-noise integrated local oscillators, a W-band lowphase-noise planar single-frequency oscillator is studied in detail, which is based on SIW resonator. The oscillator is achieved in the low-cost medium substrate usinghomemade GaAs Gunn diode. The measured results show that the output power of thisoscillator at94.78GHz is greater than9dBm, and the phase-noise is-108.56dBc/Hz@1MHz. The oscillator can obtain the proper output power, phase-noise forengineering applications and compact size.(5) In order to improve the performance, coherent work is extensively used in themodern millimeter-wave systems, which require the oscillators can be electrically tuned.The voltage-controlled oscillators (VCOs), which use varactor, have advantages of rapidtuning speed, small size, low cost and easy integration. Therefore, they are the bestchoices for present VCO designs. According to the application requests offundamental-wave locked and harmonic output frequency source circuits, which areoften applied to millimeter-wave band, a SIW millimeter-wave low phase-noisedual-port planar VCO is discussed in this dissertation. Measured results show that thedesigned VCO is able to operate in Ka-and E-band simultaneously. The output centerfrequency at the fundamental-wave output port is32GHz with the phase-noise of-114.7dBc/Hz@1MHz. The tuning bandwidth is more than120MHz, and the outputpower is6.04~8.75dBm. At the harmonic output port, the output center frequency is64GHz, and tuning bandwidth is more than240MHz with7.2~9.46dBm output power.(6) Except optimizing oscillator circuit design itself, frequency coherenttechnology also can be used to reduce the phase-noise of oscillator. For instance,Injection-Locked (IL) technology uses low-frequency high performance reference signalto realize the low phase-noise and high stability of the millimeter-wave signal.Injection-Locked Harmonic Oscillator (ILHO) is a frequently-used IL circuit structurein millimeter-wave band, and the effect of different injection powers to phase-noise ofthe locked output signals is analyzed by using different coupling at fundamental-waveinjection port in this dissertation. Conclusively, two W-band SIW ILHOs are designed,and one works at90.176GHz and another works at94.6GHz. Measured results showthat in different power injection case, the phase-noises of injection signals andfree-running oscillators have different contributions to the phase-noise of locked outputsignals. |
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