Abstract :
A new proposal-multibeam (MB) and power combining (PC) folded waveguide (FW) circuit, which can enhance the interaction efficiency and output power of terahertz (THz) traveling-wave tubes, is presented in this paper. Operating with multiple electron beams and PC means that a larger beam current and higher combining power can be obtained. First, equivalent circuit model of MB-FW is used to analyze its cold-test characteristics. Second, small signal model of MB-FW is also applied to evaluate its Pierce gain. Last, the computer simulation technology (CST) code is implemented to simulate high frequency, transmission, and interaction characteristics of MB-PC-FW. The results show this circuit can produce saturated output power of over 66 W with three electron beams in 3-dB bandwidth range of 139-144 GHz. Meanwhile the saturated output power, gain, and efficiency are 95.5 W, 36.79 dB, and 13.8% at 0.14 THz, respectively, whereas the single-beam FW circuit can only produce the saturated output power of 2.63 W in 3-dB bandwidth range of 140-143 GHz. The saturated output power, gain, and efficiency are only 2.7 W, 24.31 dB, and 1.41% at 0.14 THz, respectively.
Keywords :
equivalent circuits; power combiners; submillimetre wave tubes; terahertz wave generation; travelling wave tubes; CST code; MB-FW; PC-FW; Pierce gain evaluation; bandwidth 139 GHz to 144 GHz; cold-test characteristics; computer simulation technology; efficiency 1.41 percent; efficiency 13.8 percent; equivalent circuit model; frequency 0.14 THz; gain 24.31 dB; gain 36.79 dB; multibeam folded waveguide traveling-wave tube; multiple electron beams; power 2.63 W; power 2.7 W; power 95.5 W; power combining folded waveguide circuit; single-beam FW circuit; small signal model; subterahertz radiation; terahertz traveling-wave tubes; Bandwidth; Electron beams; Equivalent circuits; Impedance; Integrated circuit modeling; Mathematical model; Power generation; Folded waveguide (FW); multibeam (MB); power combining (PC); subterahertz (THz); traveling-wave tube (TWT); traveling-wave tube (TWT).;
