In order to increase the work frequency and output power capacity of the conventional microwave backward wave oscillator(BWO)
a compact high power THz BWO was proposed. This THz BWO consisting of a large cross-section slow wave system operated as an overmoded surface wave oscillator. The slow wave system(SWS)was constructed as follows: a series of annular slots were formed in parallel in the Phi direction along the inner wall of an overmoded cylindrical wave guide
and the distance between every two slots was equivalent. This kind of SWS decreased the field strength in the structure efficiently and enhanced the power capacity of the device obversely in the THz regime. The structural parameters were optimized with the numerical simulation method
and a set of best parameters were presented. The hot test simulation of the device was implemented with the 2.5-dimensional particle-in-cell simulation programme. Under the condition of 550 kV voltage and 350 A current
the output power of 14.4 MW was achieved at the frequency of 0.146 THz. And an efficiency of 7.5% was also obtained with a perfect time plot and fine spectrum characteristic.
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references
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