The combination of a photoconductive switch coupled to an energy storage ice wherein the switch is comprised of photoconductive semiconductor switch while the energy storage device comprises a tapered radio transmission line. A photoconductive semiconductor gallium arsenide switch is embedded in a circular disc of dielectric material having a thickness dimension which reduces linearly outward from the center, with upper and lower layers of continuous radial metallization configured in a circular pattern located thereon. The upper layer of metallization includes an apertured grid adjacent one surface of the switch, while the outer conductor of a coaxial output signal line is connected to the metallization layer on the opposite side with the inner conductor thereof passing through the dielectric layer to the undersurface of the semiconductor switch.