The design of high power microwave and millimeter-wave (MMW) voltage controlled oscillators (VCOs) is, in general, an inexact science. Development methods typically rely on qualitative circuit models and require extensive trial-and-error experimental measurements. The objective of this thesis is to demonstrate an analytical design procedure for high power millimeter-wave VCOs. First, the experimental characterization of the Gunn and varactor diodes at Ka-band are discussed. The large signal characterization of the Gunn diode employs the post-in-a-waveguide circuit modeling work of Williamson. The varactor diode characterization makes use of Getsinger's models for packaged microwave circuits to determine the varactor diode circuit parameters. The outcome of both of these efforts result in accurate models for the packaged devices. Next, the dual, post-in-a-waveguide circuit model of Joshi and Cornick is used to determine the appropriate circuit geometry necessary to achieve a set of performance goals for a Ka-band VCO. The VCO configuration was built and the experimental results are shown to validate the design procedure. The frequency of operation was 34.99 to 35.64 GHz with tuning sensitivity of 15 to 30 MHz per volt. Output power varied only 0.9 dB over this bandwidth ranging from 22.1 to 23.0 dBm.by Herbert Allan LeachIncludes bibliographical references (page 63)California State University, Northridge. Department of Engineering
