High power 35 GHz gyroklystron amplifiers

High power coherent radiation sources at 35 GHz are attractive for high gradient, compact particle accelerators and next generation high resolution millimeter wave radar/communications. A multi-cavity gyroklystron amplifier is considered a promising candidate for high power millimeter wave generation. Experiments on two-cavity and three-cavity gyroklystron amplifiers are underway to demonstrate 140 kW, 35 GHz coherent radiation amplification. Initial experiments show an efficiency of 32%, a bandwidth of 0.4%, and a saturated gain of 22 dB which corresponds to peak power of 130 kW. Experimental results are moderately in agreement with large signal simulations. Calculations also show that a stagger tuned three cavity circuit increases the bandwidth to more than 0.7%