电子回旋共振离子推力器放电室低信号调试

Regulation experiment on the discharge chamberof electron cyclotron resonance ion thruster

关键词:  电子回旋共振离子推力器  微波  谐振  信号调试

Key words:  Electron cyclotron resonance ion thruster  Microwaue  Resonance  Regulation

摘要:

微波输入技术是电子回旋共振离子推力器的关键技术之一,输入微波在推力器放电室内产生谐振的时候,微波功率才能高效地被吸收,从而电离气体,提高电子的能量,增加等离子体的电离度。电子回旋共振离子推力器放电室是一个不规则的微波谐振腔,很难从理论上确定其谐振状态下的结构。本文利用网络分析仪,采用微波无源器件回波损耗的测试方法对放电室进行精确调谐,分析微波谐振频率及带宽,目的在于详细研究放电室的结构尺寸、微波耦合探针形状和尺寸在谐振状态下的匹配性。调试结果表明放电室增加14 mm圆柱段,选择圆柱段长度22 mm和球形直径9 mm的组合探针,可以得到较好的谐振状态,此时腔体的回波损耗为-23 dB,谐振频率4.195 GHz,谐振带宽为0.025 0 GHz,品质因素为167.848。

Abstract:

The microwave input technology is one of key technologies of electron cyclotron resonance ion thruster. When the input microwave resonates in the discharge chamber, the microwave power can be absorbed efficiently. Thus gas is ionized to produce high degree plasma. The discharge chamber of electron cyclotron resonance ion thruster is an irregular microwave resonant cavity. It is difficult to determine its resonant condition and the optimum structure theoretically. Here the network analyzer and the microwave passive component return loss test method are used to tune the discharge chamber harmoniously and analyze the matching between microwave resonant state, frequency and its band width and the discharge chamber structure as well as microwave coupling probe shape. The experiment results indicate that at resonance frequency of 4.195 GHz discharge chamber with a cylinder section in 14mm length and with a combined probe of 9 mm in spheric diameter and 22 m in cylindric length the thruster discharge chamber resonant condition is at optimum state, where the return loss is lowest, -23 dB,and the band width is 0.025 0 GHz.The quality factor Q is 167.848.