An Ultra Wideband Solid State Rf Source

The generation of Ultra Wideband (UWB) RF pulses using photoconductive switches has been demonstrated. These devices exhibit 100-200 pico-second closure times when used as a switch which is optically activated within a circuit. Fundamentally, the switch is used in a pulse forming network to transfer energy from an energy storage medium, such as a capacitive system, to a load thus converting stored electrical energy to RF. The efficiency realized is on the order of 25-35%, far exceeding conventional travelling wave tubes and other electron beam devices. Rockwell International has advanced the state-of-the- art in UWB sources by incorporating Lawrence Livermore Lab photoconductive solid state switch technology into an RF generator design. The design is simple, compact, and modular thereby allowing for future switch technology infusion while increasing reliability and maintainability. The basic design calls for a Blumlein generator to be incorporated into a transmission line or "open" cavity. Each Blumlein module occupies a 1.2 cm x 12 cm x 20 cm volume and can be "stacked" vertically such that a number, N, of these stacked modules form an aperture connoted as the Mismatched Blumlein Aperture or MBA. In turn, individual MBAs may then be configured (i.e., vertically or horizontally) with appropriate spacing to form an array for generating gigawatt peak powers.