Design of circular corrugated waveguides to transmit millimeter waves at ITER
Design of circular corrugated waveguides to transmit millimeter waves at ITER
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DOI：
10.13182/fst08-a1662
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发表时间：
2008-01-01
影响因子：
0.9
通讯作者：
Doane, J. L.
中科院分区：
文献类型：
--
作者：
Doane, J. L.
ITER上大量的毫米波传输线，包括传输电子回旋加速器功率和诊断信号的线路，都需要低损耗的圆波导。为了提供低损耗传输，波导的直径需要有几个波长。波纹壁不仅在直线运行中而且在弯曲处进一步减少了损耗，并使波导对小变形具有鲁棒性。我们提出的理论计算结果表明，这些特性可以在适合ITER应用的非常宽的带宽上保持。用于进行这些计算的计算机代码是基于场的空间谐波分析。通过对波导的测量，对波纹波导的理论进行了半定量的验证。讨论了波纹几何形状、波导孔、波导结、输入高斯光束对准和波导支撑对准的公差。结果表明，波纹波导的低损耗特性对许多几何变化和理想偏差不敏感。最后，提出了一些制造方面的考虑。为了提供波导本身的更完整的覆盖，仅简要提及由于输入耦合和弯曲等元件造成的损耗。介绍了一些复习材料和一定程度的技术细节。
Low-loss circular waveguides will be needed for a large number of millimeter-wave transmission lines on ITER, including those transmitting electron cyclotron power and diagnostic signals. In order to provide low-loss transmission, the waveguides need to be several wavelengths in diameter. Corrugating the walls reduces the loss further not only in straight runs but also at bends, and makes the waveguide robust against small deformations. We present results of theoretical calculations showing that these properties can be maintained over very wide bandwidths suitable for ITER applications. The computer code used to make these calculations is based on a space-harmonic analysis of the fields. Measurements on waveguides are described that validate the theory for corrugated waveguides semiquantitatively. Tolerances on the corrugation geometry, waveguide bore, waveguide junctions, input Gaussian beam alignment, and waveguide support alignment are discussed. It is shown that the low-loss properties of corrugated waveguide are insensitive to many variations in geometry and deviations from ideality. Finally, some fabrication considerations are presented. In order to provide more complete coverage of the waveguides themselves, only brief mention is made of the losses due to input coupling and components such as bends. Some review material and some level of technical detail are both presented.