Design and Experimental Results of a W-Band Gyro-TWA With the Widest Bandwidth

This letter presents the design and experimental results of a 152-kW W-band gyrotron travelling-wave amplifier (gyro-TWA) that boasts an enhanced 3-dB instantaneous bandwidth ranging from 8.8 GHz to 12.5 GHz, and 1-dB bandwidth from 7.0 GHz to 11.5 GHz. This was achieved by powering the gyro-TWA with a 60 kV, 11 A electron beam. The amplifier demonstrates an output power exceeding 120 kW and an interaction efficiency above 19.1% within 89.8-101.3 GHz. This performance improvement was made possible by using a curved-profile circuit that matches with the gyrotron solenoid across a wide frequency band. The theoretical predictions, particle-in-cell simulations and experimental results are compared and found to be in good agreement.