Variable Polarizer

The object of this work was to study and experimentally verify design criteria for a high power S-band variable polarizer which transforms the TE10 mode to vertical linear, clockwise circular, counterclockwise circular, or horizontal linear polarizations. Design objectives include switching time less than 200 microseconds, and operation at 10 MW, 20 KW average with a 40 microsecond pulse width, over the 3.1 to 3.6 GHz range. The polarizer is required to process both transmitted and receiver signals. Breadboard phasers compatible with this concept were constructed on this program and tested for limiting, breakdown level, cooling effectiveness, and magnetostrictive effects. The breadboard phasers showed no limiting up to 3 MW peak. Breakdown levels were above 3 MW peak for 2 microsecond pulse width in units without charging wires. Pressurization and the presence of hybrid mode blips in the transmission characteristics were found to have a significant influence on breakdown level, especially for units with charging wires. Test results indicated that wavelength height reduction would be needed to eliminate higher order mode resonances. This would probably make it necessary to split power more than four ways to achieve full power operation.