Broadband Mixers for Microwave and Millimeter-wave Applications

良好特性之混波器在通訊系統中一向扮演著重要的角色，並且影響系統的非線性特性。過去混波器常以二極體或者晶體檢測器的方式實現，近年由於半導體科技的進步，主動式元件也成為實現混波器的另一種好選擇。因此，如何利用主動元件設計高頻率並同時具有良好特性的混波器是一個值得探討的重點。 本論文的主題在於使用各種半導體製程，設計並實現特性良好之微波及毫米波降頻混波器，研究的方向著重於應用於超寬頻段(UWB)之降頻混波器及毫米波頻段降頻混波器。論文主要可分為三大部分，第一部份介紹混波器的功能、原理以及各種設計混波器時需注意的參數。第二部份描述一可適用於超寬頻段之降頻混波器，先從超寬段的需求規格出發，討論傳統吉伯特單元混波器(Gilbert cell mixer)之原理及優缺點，並根據其而提出一個改良式架構來降低功率損耗，並應用寬頻輸入匹配電路以增加頻寬。論文的最後一部分主要在討論應用於毫米波頻段之降頻混波器的原理及應用，本論文提出兩個寬頻降頻混波器,並說明其設計概念與優缺點。 在本論文中，我們使用台積電0.18微米金氧半互補式製程提出一個折疉式架構的混波器，成功地實現了一個0.2-16.5 GHz之低功率雙平衡式降頻混波器。此晶片的面積僅有0.44平方毫米，其直流功率損耗為15 mW。 除了上述可應用於超寬頻段之混波器，應用於毫米波頻段的混波器亦是本論文的探討重點，首先我們利用穩懋0.15 微米砷化鎵異質接面高遷移率場效電晶體 (pHEMT) 設計了一4-41 GHz之寬頻降頻混波器，電路的主要架構是藉由分散式電路的觀念下手設計，由量測結果顯示，此電路在4-41 GHz有3-8.5 dB 的轉換增益，其直流功率消耗僅為 100 mW，晶片大小則是2 mm × 1 mm。 另一個寬頻混波器則是利用台積電0.13 微米金氧半互補式製程所設計之寬頻降頻混 波器。此電路同樣也展示了一相當寬頻的響應，2-50 GHz 皆有一大於0 dB 的轉換增益。此電路僅消耗43 mW 直流功率，在已發表毫米波頻段主動式寬頻混波器之中是最低的。晶片大小則是0.68 mm × 0.67 mmA mixer with good performance is indispensable in modern communication systems, which dominates the nonlinear effects of communication system. Therefore, to design a high frequency mixer with good performance is important. The goal of the thesis is to design and implement wideband mixers in microwave and millimeter-wave regime. This research focuses on wideband mixer for applications in millimeter-wave region and UWB wireless system. The thesis can be divided into three parts. The first part introduces the basics of mixer as well as the designing parameters. In the second part, we start from the background of UWB system and then describe the regulations of UWB system. The advantages and drawbacks of traditional Gilbert cell mixer are investigated. Based on traditional Gilbert cell mixer, we proposed a folded-topology Gilbert cell mixer to reduce the dc power consumption. Further more, we employ the LC-ladder matching circuit to extend operating bandwidth. The final part of this thesis, two distributed mixer which can be used for applications in millimeter-wave region are implemented with 0.15-um GaAs pHEMT and 0.13-um CMOS technologies. The design concept is also described. In this thesis, the folded-topology mixer was fabricated using TSMC 0.18-um CMOS technology. From the measured results, the double-balanced down-conversion mixer achieves a good conversion gain of 6-7 dB from 0.2 to 16.5 GHz with a low power consumption of 15 mW. The characteristics of low power consumption and wideband performance of the mixer are believed that the mixer is suitable for UWB wireless system applications. The chip size of the proposed mixer is 0.68 mm x 0.65 mm The design of broadband down-conversion mixers in millimeter-wave is another focused point of this thesis. The distributed (or traveling-wave) concept is adopted to design a 4 to 41 GHz broadband down-conversion mixer. The measured results show that the mixer demonstrates a wideband performance from 4 to 41 GHz with a conversion gain of 3-8.5 dB. The simulations agree to the measured results. The dc power consumption is relatively low compared with previously published work. Another distributed mixer is implemented with TSMC 0.13-um CMOS. The mixer has a measured conversion gain of better than 0 dB from 2 to 50 GHz. Compared with published works, the mixer consumes the lowest dc power of 43 mW among the active broadband mixers in MMW regime. The chip size is 0.68 mm x 0.67 mm.CONTENTS Abstract Chapter 1 Introduction................................................................................1 1.1 Background and Motivation...................................................................1 1.2 Literature Survey..................................................................................2 1.3 Contributions.......................................................................................4 1.4 Chapter Outline...................................................................................5 Chapter 2 General Background of Mixer......................................................7 2.1 Introduction.........................................................................................7 2.2 Mixer Fundamental..............................................................................9 Chapter 3 Design of the Ultra-Wideband Mixer...........................................19 3.1 Fundaments of Distributed Circuits......................................................19 3.1.1 Introduction....................................................................................19 3.1.2 History of UWB Technology.............................................................20 3.1.3 Regulations....................................................................................21 3.2 Ultra-wideband Mixer Design..............................................................23 3.2.1 Foundry Description........................................................................23 3.2.2 The Basic of the Gilbert Cell Mixer...................................................24 3.2.3 The Design of UWB Mixer...............................................................27 3.2.4 Measurement Results.....................................................................35 3.3 Performance Summary. ....................................................................44 Chapter 4 Design of Broadband mixer.......................................................46 4.1 Ultra-wideband Technology Overview...................................................46 4.2 A 4~41 GHz Distributed Mixer using Win 0.15-um pHEMT Process.......51 4.2.1 Foundry Description........................................................................51 4.2.2 Distributed Mixer Design.................................................................51 4.2.3 Measurement Results.....................................................................60 4.2.4 Performance Summary...................................................................65 4.2.5 Discussion....................................................................................66 4.3 A 2-50 GHz Distributed Mixer using 0.13-um CMOS Technology...........69 4.3.1 Foundry Description.......................................................................69 4.3.2 The Distributed Mixer Design using CMOS Technology......................70 4.3.3 Measurement Results.....................................................................80 4.3.4 Performance Summary...................................................................86 Chapter 5 Conclusions............................................................................87 References.............................................................................................8