TE01模磁旋返波振盪於模式選擇線路之研究

TE01 Gyrotron Backward-Wave Oscillator with Mode Selective Circuit

陳乃慶(Nai-Ching Chen)

指導教授 ： 張存續 ； 朱國瑞

國立清華大學/理學院/物理學系/博士(2009年)

https://doi.org/10.6843/NTHU.2009.00037

摘要

Gyrotron backward wave oscillator (gyro-BWO) is a frequency tunable high power source in millimeter and sub-millimeter region. The broadband tunability of gyro-BWO has been demonstrated in NTHU by operating the fundamental TE11 mode at Ka-band. To push forward the operating frequency up to sub-terahertz region, high order mode operation is more favorable due to the structure size limit. TE0n mode, features low dissipation on wall loss, has the advantage of continues-wave operation at small interacting structure. Thus a Ka-Band fundamental harmonic (s=1) gyro-BWO is one of the best candidates of preliminary study for high frequency microwave source. Owing to the high order mode operation, the stability and tunability of the gyro-BWO deteriorate severely by mode competition. A single mode, steady-state code is employed to analyze both the starting behavior of the spurious oscillations and interacting efficiency of the operating mode. The lower order transverse mode tends to constitute the competition at lower magnetic field of operating tuning range. As the magnetic field tuning up, the higher order transverse mode starts to resonate and travels with lower group velocity which turns into another detrimental. A reduced interaction structure might be a solution to suppress these unwanted oscillations. However, the performance of a gyro-BWO is greatly limited as well. This dissertation devotes to design the selective circuit for TE01 mode on the basis of field profile. The effects of transverse slice and sector waveguide on spurious modes are analyzed by HFSS software. The structure length and taper geometry are thus optimized without misgiving of mode competition. The experiment result reveals that a TE01 gyro-BWO with multiple transverse slice could provide an extremely broad stable tuning range from 31.4 GHz to 36.4 GHz. The peak interacting efficiency is 23.7 % which yields 100 kW at Ib=4.5 A and Vb=93.6 kV

關鍵字

磁旋管 ； 磁旋返波振盪器 ； 高次模 ； TE01 ； 模式選擇線路 ； Sector Transducer ； Tansverse Slice

並列摘要

無資料

並列關鍵字

Gyrotron ； Gyro-BWO ； High Order Mode ； HASH(0x87ecec0) ； Mode Selective Circuit

參考文獻

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