00000ctm a22000004a 4500 UP-99796217602381238 Buklod 20230503092542.0 m |o d | ta 080209s1996 xx r |||| u|eng d (iLib)UPD-00000125265 DML eng DMLUC LG 995 1996 E6 O37 Ochave, Victorio E. A. Nonlinear modeling and circuit optimization of GaAs MESFET oscillators Victorio E.A. Ochave, Jr. 1996. 333 leaves ill. Computer print-out. Thesis (M.S.)--University of the Philippines, Diliman. A nonlinear optimization procedure to design power-optimum GaAs MESFET microwave oscillators is investigated and implemented in this thesis. The method aims to eliminate the empirical nature of microwave oscillator design. To carry out the procedure, a large-signal GaAs MESFET model is constructed; the model simulates device breakdown and accounts for the frequency dispersive behavior of output conductance. A direct extraction of small-signal model elements is undertaken, while the large-signal model parameters are obtained using a simultaneous fitting of measured device DC and RF data to nonlinear expressions representing optimizer in conjunction with a quasi-Newton scheme is employed in the extraction of the large-signal model parameters. The harmonic balance method is used to compute the steady-state terminal currents, while a coupled random-gradient optimizer is used to search for the optimum device port voltages that will induce the device to operate at prespecified conditions. The nonlinear design method is shown to result in GaAs MESFET oscillator designs that operate nearer the desired frequency of operation and with higher RF output power, compared to circuits designed using conventional methods. Oscillators, Microwave. Metal semiconductor field-effect transistors. Oscillators, Electric. Thesis Fi UP UPD DARCHIVES LG 995 1996 E6 O37 UPD DENG-II LG 995 1996 E6 O37 Thesis