| abstract |
A folded waveguide gyrotron-traveling-wave-amplifier comprises: an electron gun for transmitting an axis-encircling beam of electrons with large transverse energy along a first path having an axis; an RF source for producing and applying in a second path an RF input millimeter wave signal having a bandwidth in a preselected frequency domain and having a transverse electric field; a source for generating a solenoid magnetic field parallel to the axis along the first path; a beam collector; and an interaction circuit such as an H-plane bend serpentine waveguide positioned within the solenoid magnetic field and having a narrow wall containing a beam tunnel hole for passing the axis-encircling beam of electrons therethrough to the beam collector, an output end, and an input end for receiving and passing the RF input millimeter wave signal through the H-plane bend serpentine waveguide to the output end to modulate the axis-encircling electron beam, the modulated axis-encircling electron beam amplifying the RF input signal and also broadening the instantaneous bandwidth of the amplified RF input signal through the negative mass instability in the fundamental forward space harmonic of both fast and slow wave regions in the preselected frequency domain. In a second embodiment, a double-ridged TE folded waveguide is used in place of the H-plane bend serpentine waveguide. In a third embodiment, there is no RF input signal and the interaction circuit generates an RF signal which is outputted from one of the input and output ends. |