Generating Bipolar Nanosecond Pulsed Electric Field using Open Circuit Transmission Line Technique and Avalanche Transistors

A nanosecond pulse electric field generator based on relatively slow charging and rapid discharging of an open circuit co-axial transmission line through a stack of avalanche transistors operating as a fast switching element, is demonstrated. This low-cost circuit design produces well defined symmetrical bipolar nanosecond pulsed electric fields with rise and fall times less than a nanosecond. The pulse polarity (monopolar negative, monopolar positive or bipolar), duration, repetition rate and amplitude are user controllable. The new pulse generator opens the opportunity for use in a range of medical applications, including tissue sparing tumour ablation, where only the cancerous cells are destroyed.