LOW COST RF INTERACTION CIRCUITS FOR HIGH POWER TWTS

STAR MICROWAVE HAS DEVELOPED A NEW CONTRA-WOUND HELIX DERIVED HIGH POWER TWT INTERACTION CIRCUIT WHICH CAN BE PRODUCED FOR A FRACTION OF THE COST OF EXISTING COUPLED CAVITY CIRCUITS. INITIAL COLD TESTS INDICATE THAT THE CIRCUIT WILL PROVIDE UP TO TWICE THE GAIN PER WAVELENGTH AN DEFFICIENCY OF COUPLED CAVITY CIRCUITS, IS FREE OF OSCILLATION MODES AND CAN BE TAILORED FOR BANDWIDTHS FROM 5% TO 1/3 OCTAVE AT ALL POWER LEVELS NOW ADDRESSED BY COUPLED CAVITY TWTS. THE CIRCUITS IS PRODUCED FROM SOLID COPPER TUBING USING TRAVELING WIRE EDM, A TECHNIQUE OF SUCH PRECISION THAT THE CIRCUIT CAN BE USED AT FREQUENCIES THROUGH 44 GHZ. IN PLACE OF THE CUSTOMARY DIELECTRIC SUPPORT RODS, THE CIRCUIT IS BRAZED INSIDE A BERYLLIA TUBING. THE CONSTRUCTION PROVIDES COUPLED CAVITY AVERAGE POWER CAPABILITY. EVEN MORE IMPORTANTLY, IT OVERCOMES THE PEAK RF POWER BREAKDOWN PROBLEM WHICH HAS PREVIOUSLY LIMITED HELIX DERIVED CIRCUITS TO MODEST PEAK POWER LEVELS. THE FIRST OBJECTIVE OF PHASE I IS TO COLD TEST AND DOCUMENT CIRCUITS WHICH WILL BRACKET ALL OF THE ARMY'S NEEDS FOR HIGH POWER TWTS FROM 1 THROUGH 44 GHZ. THE SECOND OBJECTIVE IS TO VALIDATE THE REQUIRED CIRCUIT/BEO BRAZING TECHNIQUES.