Internal Microwave Propagation and Distortion Characteristics of Traveling-Wave Amplifiers Studied by Electrooptic Sampling

The internal signal propagation and saturation characteristics of two monolithic microwave traveling-wave amplifiers (TWA) are measured by electrooptic sampling. Gate and drain line responses are compared with theory and simulation, leading to revisions in the FET models. Drain voltage frequency dependence and harmonic current propagation together lead to more complex saturation behavior than is discussed in the literature.