Ka頻段高功率雙通道微波旋轉耦合器

Ka-band High Power Dual-Channel Microwave Rotary Joint

侯語辰(Yu-Chen Hou)

指導教授 ： 張存續

國立清華大學/理學院/物理學系/碩士(2013年)

https://doi.org/10.6843/NTHU.2013.00544

摘要

高功率多通道微波旋轉耦合器(Microwave Rotary Joint)是雷達系統中的關鍵角色。本論文將分別探討圓形TE01及TM01模式轉換器的高功率設計方案，由於TE01與TM01的場型彼此正交並兼具圓對稱特性，將兩組雙模式轉換器共軸心對接後可形成具有高隔離度且穿透效率不受旋轉角度影響的雙通道微波旋轉耦合器。利用HFSS模擬理論設計，考慮截止頻率因素，TM01模式轉換器的輸出端必須銜接TE01模式轉換器的截止端，接合處的結構經過優化以降低反射；對接雙模式轉換器的旋轉端因加入培林而存在間隙，須另外設計微波扼流結構(Choke)以防止TM01波外洩。
實驗結果顯示TE01及TM01模式轉換器均能達到穿透效率-1dB以上極寬的頻寬(15%)，雙模操作頻帶高度重疊且具有-50dB的極佳隔離度，穿透效率不受旋轉角度影響。

關鍵字

微波旋轉耦合器 ； TE01模式轉換器 ； TM01模式轉換器

並列摘要

High power, multi-channel microwave rotary joint plays a critical role in radar systems. This thesis proposes the high power designs of circular TE01 and TM01 mode converters respectively. Due to the orthogonality of the field profile between TE01 and TM01 mode, a pair of the high power, dual-mode converters with back-to-back connection can be developed into a high isolation, dual-channel microwave rotary joint. HFSS is employed to separately design every component. Considering the effect of the cutoff frequency, TM01 wave must pass through the cutoff section of the TE01 mode converter. The connecting section is important for the converting efficiency, the operating bandwidth, and the isolation for the dual-mode converter. A gap for implanting a bearing exists in the middle channel of the rotary joint, therefore, a microwave choke is designed to prevent the leakage of TM01 wave.
The experimental result yields a broad -1-dB transmission bandwidth of 15% for both TE01 and TM01 channels. The operating bandwidth for dual channels is highly overlapped with a high isolation of -50-dB between the channels. The transmission efficiency is independent of rotated angles since the field profile of TE01 mode and TM01 mode are azimuthal symmetric.

參考文獻

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