Intensity of electric field radiating from high-power pulsed electromagnetic wave generator for use in biological applications

Abstract

Cancer treatment is one of several new applications which use nanosecond and subnanosecond high-voltage pulses. This study focuses on the design of a compact highpower pulsed electromagnetic wave generator using a nanosecond pulsed power generator to apply a high-intensity electric field for the treatment of cancer; the pulses cause apoptosis in cancer cells. We applied an L-C inversion circuit to the pulsed power generator to obtain a voltage waveform with a single frequency, which is applied to an antenna. A water gap switch and water capacitors were used in the L-C inversion circuit to obtain a pulsed voltage with a frequency element of 250 MHz. In this experiment, an electromagnetic wave was radiated underwater by a loop antenna. A measuring double loop antenna placed 0.15 m and 0.3 m from the radiating antenna detected electric field intensities of 112 kV/m and 49 kV/m, respectively. A focusing bowl was attached to the radiating antenna to obtain a higher electric field. The electric field intensity of the radiating antenna with the focusing bowl, 300 kV/m, was 6 times higher than that without the focusing bowl. The intensity distribution of the electric field focused by the focusing bowl was measured. A measuring small loop antenna detected peak electric field intensity of 11.3 kV/cm at a focal point. Areas with electric field intensity greater than 10.8 kV/cm were approximately 5 mm square and 3 mm wide in the x-z plane and y-axis, respectively.