改进稳态行波管场论大信号互作用模型,将工作频率考虑为最小公因子基波的整数倍,采用频域等效粒子模拟算法,求解离散化亥姆霍兹方程获得空间电荷场数值解,建立半解析半粒子的2.5维行波管多频互作用模型,模拟多频工作时行波管中信号间的交调和互调的非线性特性,计算结果与L波段螺旋线行波管的互调、三阶和五阶交调试验比较具有较好的一致性。
A semi-analytical,semi-particle,2.5-dimension,multi-frequency interaction model was developed to numerically simulate the cross-modulation and inter-modulation of the large signal of the traveling wave tube(TWT),operating in a multi-frequency mode.In the simulation,the operating frequencies were assumed to be integer multiples of a base frequency,i.e.,the lowest frequency;and the space charge field distributions were evaluated by solving the discrete Helmholtz equations,assisted by the modified particle-in-cell method.The simulated results in the two-tone simulation agree fairly well with the experimental results involving the inter-modulation,and the 3rd and 5th cross-modulation of an L-band TWT.