Self-sustaining High-power RF Signal Generation Using LDMOS Based Power Amplifier and Nonlinear Transmission Line

Nonlinear transmission lines (NLTL) are gaining extensive research focus as a way to generate high-power radio frequency (RF) signals. NLTLs can be classified into two groups: lumped transmission lines containing L-C sections, and external magnetic field-biased line loaded with continuous ferromagnetic materials known as gyromagnetic lines. Traditionally, without a continuous supply of input excitation, NLTLs cannot produce self-sustaining RF signals. In this regard, the authors present a design and demonstration of a self-sustaining soliton generator. The design is based on a 16-section Schottky diode-based NLTL prototype complemented by a solid-state switch (LDMOS) based 1.5 kW (continuous) rated power amplifier (PA), and a custom-made high voltage (650 V) pulse generator. A closed-loop configuration constructed from these components can produce a continuous stream of RF signals from a single input excitation. The prototype is able to generate a peak pulsed RF power of 2.1 kW across a 50 Ω resistive load. To the best of the authors’ knowledge, solid-state switch-based PA has not been introduced in any NLTL design until now to produce self-sustaining RF signals.