Study of monolithic nonlinear transmission lines (NLTLs) on gallium arsenide molecular beam epitaxial wafer.

摘要

Both the physics of nonlinear phenomena on a nonlinear transmission line (NLTL) system and its applications have been investigated. An exact counterpart of the 1-D exponential lattice model, proposed by M. Toda, was built by utilizing microfabrication and MBE techniques. An advantage of the current approach over previous lumped element circuits is that it precisely reproduces the physics of the model without depending upon mathematical manipulations and corrections. The experimentally measured pulse shapes for the NLTL Toda soliton system were compared against calculated results, with good agreement.; In the second part of this thesis work, application of stacked heterojunction devices to NLTL has been numerically investigated to improve the performance of NLTLs. These devices, the Multi-Quantum Barrier Varactor (MQBV), the Schottky Quantum Barrier Varactor (SQBV) and the Schottky Superlattice Quantum Barrier Varactor (SSQBV), are predicted to offer significant advantages over the conventional Schottky varactor because of their stronger C-V nonlinearities, symmetric C-V characteristics, high cutoff frequency and increased breakdown voltages. An improved model in which the effects of skin losses, line parasitics and device leakage current has been proposed and employed in the simulation. These new devices are shown to be useful in high power ultra short pulse and high power harmonic generation applications.