Nonlinear Analysis of Coaxial Gyro-Travelling-Wave-Tube Amplifier

A set of nonlinear self-consistent equations in the electron guiding center coordinates is derived for the study of the behavior of the coaxial gyro-travelling-wave-tube (gyro-TWT) amplifier. It is found that the input signal grows faster and gets saturated earlier with the increasing of b/a (ratio of the inner to outer radius). Using an electron beam of 90kV, 10A and velocity ratio of 1.0 with 3% axial velocity spread, 275kW peak output power is obtained by calculation over the frequency range of 31.22–33.52GHz, the gain, efficiency and bandwidth are 47.4dB, 30.5% and 7.5%, respectively.