An improved Ku-band TTO with compact solenoid and better plasma-suppressing collector

A Ku-band transit-time oscillator (TTO) with compact magnetic coil and a novel collector structure is proposed. By utilizing the natural bending of the magnetic field, this TTO could decrease over 25% length of uniform magnetic field and the required energy of the solenoid. Besides, the larger radius and decreased magnetic field at the collector lead to larger collection area and less current density in collector surface, simulation shows that the energy deposition peak is 2.5 times less in this novel collector. That this novel collector also has evident advantages in suppressing the adverse effect of plasmas than traditional one in simulation, when hydrogen gas is preset on the collector surface. Particle-in-cell simulation shows that with a 2.4GW beam guided by a decreasing magnetic field of about 0.7T, 0.85GW microwave power pulse at 13.23GHz is generated in this TTO, yielding a conversion efficiency of about 35.4%.