A dielectric rod antenna driven by a pulsed power system

A dielectric rod antenna was constructed for stimulating biological tissues. The antenna consists of three sections (a conical wave launcher, a cylindrical waveguide, and a conical emitting section). The simulation of the antenna in free space was confirmed with measurements of the return loss (S11) and the transient electric field. To reach the electric field threshold for tissue stimulation, a high voltage pulsed power system was designed and constructed to drive the antenna. Central to the pulsed power system is a transformer and an oil peaking switch. The transformer is an ultrafast, dual resonance pulse transformer with a linearly integrated primary (LIP) stage. It is capable of generating pulses with rise time <;50 ns. The load for the transformer was an oil-filled transmission line that was connected to the antenna. An oil peaking switch was used to switch the line to produce high voltage picosecond transients. The electric field was measured in the near field at a distance of 4 cm. A 500 ps pulse with an amplitude of 600 V/cm was recorded for a 25 kV input from the pulse transformer. These results demonstrate the feasibility of the system and so future work will be focused on increasing the voltage and the electric field in order to stimulate biological tissues.