Coupling of tilting Gaussian beam with hybrid mode in the corrugated waveguide
Coupling of tilting Gaussian beam with hybrid mode in the corrugated waveguide
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DOI：
10.1007/bf02677895
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
K. Ohkubo;S. Kubo;H. Idei;M. Sato;T. Shimozuma;Y. Takita
中科院分区：
文献类型：
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作者：
K. Ohkubo;S. Kubo;H. Idei;M. Sato;T. Shimozuma;Y. Takita
本文讨论了回旋管输出的高斯光束与直径为2的圆形波纹波导中的混合模匹配时的模转换损耗。通过数值计算发现，波长为λ的TEM 00模以偏置或倾斜方式注入时，损耗显著增加，最佳束腰尺寸w 0发生变化。通过对数值数据的多项式拟合，得到了当w_0/a=0.643时，离轴位移和倾角θ的损耗定标公式分别为2.3（rd/a）~ 2- 2.2（rd/a）~ 4和3.9（aα/λ）~ 2- 5.6（aθ/λ）~ 4。在168 GHz和2a=88.9 mm的频率下，为了保持模式转换损耗≤1%，倾斜角和偏移应分别小于0.1度和2.9 mm。
The mode-conversion loss in the matching between the gaussian beam emanated from the gyrotron and the hybrid mode in the circular corrugated waveguide with the diameter of 2ais discussed. By numerical calculation, it is found that the loss considerably increases and optimum waist sizew0changes when TEM00mode with the wavelength λ is injected with offset or tilt. By fitting numerical data to the polynomial function, it becomes evident that the scaling formulas of the losses for the off-axis shiftrdand for the tilt angle θ are derived to be 2.3(rd/a)2– 2.2(rd/a)4and 3.9(aα/λ)2– 5.6(aθ/λ)4for fixedw0/a=0.643, respectively. To keep the mode-conversion loss ≤1% for the frequency of 168 GHz and 2a=88.9 mm, tilting angle and offset should be less than 0.1 degrees and 2.9 mm, respectively.