详细研究并设计了一个由Vlasov螺旋开口辐射器和两级曲面反射器组成的边廊模回旋管准光模式变换器.首先采用几何光学理论研究了设计的Vlasov型准光模式变换器的工作机理,在此基础上,再利用矢量绕射理论中的口径场积分法和表面电流积分法编写了模拟仿真程序,最后结合W波段边廊模回旋管的具体设计参数,应用所编写程序详细分析了工作模式在此变换器中的模式变换过程.模拟结果表明,W波段回旋管中的TE12,2边廊模在输出窗处被转换为能量集中的准Gauss波束.
A quasi-optical mode converter for a whispering-gallery mode gyrotron,consisting of a Vlasov helically-cut launcher and two curved-mirror reflectors,is studied and designed.Firstly,the operation mechanism of the Vlasov type quasi-optical mode converter is investigated using geometric optics theory.And then,applying the aperture field integration and the surface current source integration of the vector diffraction theory,a numerical simulation code is programmed.Finally,the code is used to study a quasi-optical converter system of a W-band whispering-gallery mode gyrotron,and the operation mechanism of the mode conversion in the converter is revealed in detail.Numerical results indicate that the TE12,2 whispering-gallery mode inside the W-band gyrotron is converted into a highly Gaussian-like beam at the output window.