State Variable Harmonic Balance Simulation of a Quasi-optical Power Combining System

CHRISTOFFERSEN, CARLOS ENRIQUE. State Variable Harmonic Balance Simulation of a Quasi-Optical Power Combining System. (Under the direction of Michael B. Steer.) A state variable implementation of harmonic balance circuit analysis is developed. The equations are formulated with the minimum number of unknowns starting from the modified nodal admittance matrix of the linear part of the circuit. The program uses advanced numerical techniques, such as automatic differentiation for calculating the Jacobian of the system. One key feature of the program is that it is easy to add new types of nonlinear elements and several numeric methods can be used to solve the harmonic balance equations. The program is tested by simulating a quasi-optical grid and comparing the results with measurements. Also, different numerical methods to solve the nonlinear equations are compared, and conclusions are made. STATE VARIABLE HARMONIC BALANCE SIMULATION OF A QUASI-OPTICAL POWER COMBINING SYSTEM by CARLOS ENRIQUE CHRISTOFFERSEN A dissertation submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the Degree of Master of Science ELECTRICAL ENGINEERING