Investigation of a Novel Planar Meander Slot-Line Slow-Wave Structure

A novel planar meander slot-line slow-wave structure (MSL-SWS) configuration for a Q-band traveling wave tube (TWT) is proposed and investigated. Consisting of a thin metal sheet graved with a meander slot and a metal enclosure, the MSL-SWS can combine massive production and good heat dissipation. The high-frequency characteristics are obtained by numerical simulation and validated by experiment. The PIC simulation results suggest that for an 8.2 kV and 0.1 A sheet electron beam, the output power can reach 49 W at 40 GHz with a gain of 26.9 dB. A 3-dB bandwidth of roughly 15% centered at 40 GHz is also indicated. The proposed configuration is manufactured using laser cutting and computer numerical control (CNC) milling technology. Experimental confirmation that insertion losses can be reduced to 0.043 dB/mm by plating the MSL-SWS with copper. With a good potential for fabrication, this structure can be good candidate for millimeter TWT applications.