Analysis of the effect of field non-uniformity on energy conversion efficiency in a cyclotron-wave rectifier.

The cyclotron-wave rectifier can efficiently convert microwaves into direct current in wireless power transmission. Its resonator operates in the quasi-H₁₁₁ mode, where there is field non-uniformity; how this field non-uniformity will affect the energy conversion is determined. In this paper, through Computer Simulation Technology simulation, combining experiential analysis with numerical fitting obtains the field expression of the operating mode, approximately calculates the Coulomb field by using the model of a filamentary electron beam, and then through the numerical solution, analyzes the effect of the field non-uniformity on the energy conversion efficiency in both the resonator and the conversion region. The results demonstrate that when the relationship between the beam current I₀ and the beam radius r_obr satisfies the Brillouin relationship, a lesser current density can maintain the beam shape very well and ensure a high beam-wave interaction efficiency; furthermore, in a reverse magnetic field region, when I₀ ≤ 0.75I_obr, a higher energy conversion efficiency can be predicted. What is more, the conclusion is in agreement with particle-in-cell simulation. Finally, numerical computation also indicates that high beam-wave interaction efficiency requires a smaller radius of the electron beam. [ABSTRACT FROM AUTHOR]