微波及毫米波寬頻系統關鍵元件之研究

Research on Key Components for Microwave and Millimeter-Wave Wideband Systems

高瑞智(Jui-Chih Kao)

指導教授 ： 王暉

國立臺灣大學/電機資訊學院/電信工程學研究所/博士(2013年)

https://doi.org/10.6342/NTU.2013.02070

摘要

本篇論文中提出了三個寬頻的電路設計，其中包含了一改良式魏金森分功器及其應用、一寬頻分佈式放大器，以及一擁有寬中頻頻寬的三疊接降頻混頻器。
改良式魏金森分功器使用了一頻率相關之隔離網路以拓寬隔離度之頻寬。利用本文中所提及之方法，使得以魏金森作為基礎設計之特定功用分功器(功率均分、功率不均分、多路，以及特定相位差輸出)可以在不犧牲中心頻率之隔離度前提下，達到相當寬的隔離頻寬。實驗結果中，改良式魏金森分功器擁有之比例操作頻寬(此頻寬定義為擁有大於10dB之折返損耗、小於1dB之入射損耗，及大於20dB之隔離度特性之交集)皆大於105%。這些實驗的結果也驗證了論文中所提出的概念。
寬頻的分佈式放大器採用了嶄新的結合架構以達到較高的增益與輸出功率，以及較低的雜訊指數。這個電路結合了傳統的分佈式放大器以及串接單級分佈式放大器，並且從中利用各架構之優點。此外，更利用了級間終端移除技術得到更高的增益。本文的第三章中，利用一0.18微米互補式金氧半導體製程所製作的分佈式放大器來驗證所提出之理論及架構。本電路使用了0.83mm2之電路面積及238mW的直流功耗，並且在2 GHz至35 GHz頻段內擁有24dB之增益及523之增益頻寬乘積、高於5dBm之輸出功率，以及低於7.5dB之雜訊指數。其電路之量測結果非常接近設計時之模擬結果。
最後，本論文利用0.15微米假型高速電子遷移率電晶體製程實現了一個操作在W頻段的三疊接降頻混頻器，此混頻器具有寬中頻頻寬及高本地振盪埠至射頻埠隔離度之特性。在此電路中，利用改良式電阻式混頻核心及巴特沃斯形式低通濾波器達到較寬的中頻頻寬。並且利用三疊接之電路架構，在增加非常小的電路面積下大幅改善本地振盪埠至射頻埠的隔離度。為了更精確的預測此電路在W頻段之特性，本電路中的電晶體模型使用了自行萃取製作的安傑洛夫模型(Angelov model)。本電路使用了1mm2之電路面積，以及24mW之直流功耗。從量測結果中可以得知，在本地振盪源頻率為86GHz時，此混頻器有25GHz之中頻頻寬，且頻寬內之轉換增益皆大於-13dB，各埠之間的隔離度皆優於38dB。而在本地振盪源頻率為96GHz時，此混頻器仍可提供約25GHz之中頻頻寬，且頻寬內之轉換增益皆大於-14dB，各埠之間的隔離度則優於29dB。

關鍵字

魏金森分功器 ； 分佈式放大器 ； W頻段 ； 假型高速電子遷移率電晶體

並列摘要

In this thesis, three wideband circuits are presented, including a modified Wilkinson power divider and its applications, a broadband distributed amplifier, and a wide IF bandwidth triple cascode down-conversion mixer.
The modified Wilkinson power divider uses a frequency dependent isolation network to extend its isolation bandwidth. Using the proposed design methods, the specific Wilkinson-based power divider (equal, unequal, multi-ways, and specific phase difference output) can achieve very wide isolation bandwidth without sacrificing the isolation at the center frequency. The operation fractional bandwidths for the modified Wilkinson power dividers, which are determined by the intersection of 10-dB return loss, 1-dB insertion loss, and 20-dB isolation, are better than 105% in the experiments. The realized examples demonstrate the concept for the isolation bandwidth extension very well.
The broadband distributed amplifieruse a novel combination topology for higher gain, higher output power, and lower noise figure. This circuit combines the conventional distributed amplifiers and cascade-single-stage distributed amplifiers, and takes the advantages of them. Also, the interstage termination removed technique is used in this design for higher gain. A 0.18-μm CMOS distributed amplifier is realized to demonstrate the design concepts in chapter 3. The amplifier costs 0.83-mm2 circuit area and 238-mW power consumption, and it obtains 24-dB gain, 523 gain-bandwidth product, 5-dBm output power, and 7.5-dB noise figure from 2 GHz to 35 GHz. The measured results agree with the simulation very well.
Finally, a W-band triple cascode down-conversion mixer with wide IF bandwidth and high LO-to-RF isolationis fabricated in 0.15-μm pHEMT. In this circuit, the modified resistive mixing core and the Butterworth type low pass filter are designed for wide IF bandwidth. The triple cascode topology improves the LO-to-RF isolation with very small extra circuit area. To estimate the circuit performance more precisely in W band, the Angelov transistor models are made and used in the design. The circuit occupies 1-mm2 chip area and 24-mW power consumption. The measured results show that this mixer can provide 13-dB conversion gain, 25-GHz IF bandwidth, and 38-dB port-to-port isolation when the LO frequency is 86 GHz, and 14-dB conversion gain, 25-GHz IF bandwidth, and 29-dB port-to-port isolation when the LO frequency is 96 GHz.

並列關鍵字

Wilkinson power divider ； distributed amplifier ； W band ； pseudomorphic high electron mobility transistor

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