Self-Excitation Thresholds in RF Structures

A theory and general method for calculating self-excitation thresholds for a large class of standing and traveling-wave structures used in amplifiers, klystrons, traveling-wave tubes, and other vacuum electronic devices (VED) is presented. One determines the circuit parameters of RF structures that are changed due to the presence of electron beam and analyze the stability of the obtained matrices. New determinant equations defined by such stability matrices are derived in a general form applicable to any RF structure and as an important special case for RF structures with electron beams. The theory and computational methods described here are essential for stability analysis of RF structures and VED.