在這裡提出用來增加壓控振盪器頻率可調範圍的動態基板變容器。不同於已往反轉式變容器，動態基板架構保證可以作用於強反轉區並且得到最大的變容值藉由穩定變容器兩端點的電壓。量測結果顯示相較於傳統設計此設計增加了兩倍的頻率可調範圍。在這裡，我們使用標準0.18 um的CMOS製程設計及製作一個5 GHz的壓控振盪器。使用0.6 V的供應電壓，此壓控振盪器擁有百分之二十的頻率可調範圍，相位雜訊為-118 dBc/Hz於1-MHz的起始頻率，功率消耗為4 mW。從結果也可看出在動態基板偏壓下的壓控振盪器能操作在更低的電壓下。

A novel dynamic-bulk-bias (DBB) varactor is proposed, to increase frequency tuning rang of a VCO. Different from the conventional inversion-mode varactor, the DBB structure can stabilize the voltage across the varactor, which ensures the varactor to operate in the strong inversion region and gains the largest capacitance tuning range. The measurement result shows the proposed design increases the frequency tuning range by 2 times larger than that of the conventional VCOs. Here, a 5 GHz VCO is designed and fabricated by using a standard 0.18 um CMOS process. From a 0.6-V supply voltage, the VCO exhibits a frequency tuning range of 20%, a phase noise of -118 dBc/Hz at 1-MHz offset frequency and a power consumption is 4 mW. The result also shows that the DBB based VCO can operate at a lower supply voltage.

Chapter 1 Introduction 1
1.1 Background and Problems 1
1.2 Related Works and Motivation 2
1.3 Thesis Organization 3
1.4 Reference 3
Chapter 2 Performance Parameters 6
2.1 Performance Parameters 6
2.2 Capacitance Tuning Ratio (Cmax/Cmin-ratio) 6
2.3 Quality Factor (Q) 6
2.4 CV-characteristic 9
2.5 Self resonance frequency 10
Chapter 3 Varactor Concept 12
3.1 Varactors 12
3.2 MOS Varactor 13
3.3 Inversion-mode MOS Varactor 15
3.4 Accumulation-mode MOS Varactor 16
3.5 Reference 22
Chapter 4 The Proposed Dynamic-Bulk-Bias Varactor Topology Use In VCO 24
4.1 Varactor types 24
4.2 Dynamic-Bulk-Bias Varactor Topology 25
4.3 The Proposed Varactor Topology Use in VCO 28
Chapter 5 Circuit Implementation 30
5.1 Circuit Implementation 30
5.2Experimental Results 33
5.3 Reference 37
Chapter 6 Conclusion 38
Conclusion 38

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