A modular PFN with pulsewidth agility

This paper describes the design, analysis, and realization of a lightweight, low-impedance pulse-forming network (PFN) in which identical inductor-capacitor modules can be added or removed to change pulsewidth while maintaining high pulse quality without introducing excessive pulse-top perturbations. The PFN evolved contains an input module that is optimized for a pulse-plateau ripple of ±0.5 percent. The ripple remains within this limit as modules are added or removed from the PFN to change the pulsewidth in 2-µs steps. The optimized parameters are presented in normalized form allowing the optimum response to be achieved for arbitrary pulsewidths and network impedances. This low-ripple response is achieved without incorporating mutual inductance into the design, therefore, easing the module tuning and assembly. Mutual inductance has been considered indispensible in PFN´s, but it is a roadblock for modular construction. Its elimination as a design parameter is the key to realizing the modular PFN. A breadboard was built and tested under high power. Included are measured responses that verify that the modular concept and optimum response can be realized in practice.