摘要
在現在通訊系統中，低相位雜訊的壓控振盪器是不可或缺的元件，尤其在高階的數位調變系統，如正交振幅調變(n-QAM)與相位振幅調變(n-PSK)。因此如何設計一個具有低相位雜訊的壓控振盪器是值得探討。 本論文研究主題在於使用鉮化鎵異質接面雙極性電晶體及互補式金氧半場效電晶體製程，設計實現低相位雜訊壓控振盪器。論文主要可以分為三大部份，首先是介紹振盪器的設計與應用，並同時實現一個Ku頻段的壓控振盪器。接下來是描述π型回授振盪器原理及優點，並實現一個應用於Q頻段的平衡π型回授的壓控振盪器。論文的最後一部份主要在討論四相位振盪器之直接升頻正交調器的原理及應用，並實現15 GHz的四相位振盪器之直接升頻正交調器。 首先我們使用穩懋半導體2-μm鉮化鎵異質接面雙極性電晶體製程製作一個 應用於Ku 頻帶的壓控振盪器，可調頻率範圍從14.6 到16.6 GHz，其相位雜訊在 1-MHz位移時為-112.5 dBc/Hz。另外，在核心電路偏壓電流為12.5 mA及偏壓 為2 V 時，此壓控振盪器可提供最大輸出功率為6.9 dBm。此壓控振盪器擁有低 相位雜訊及寬的可調頻率優點。另外，本論文呈現設計了一個使用平衡π 型回授的Q 頻段壓控振盪器。此 壓控振盪器同樣是使用穩懋半導體2-μm鉮化鎵異質接面雙極性電晶體製程設計 製作。在核心消耗功率為20 mW 下，，其可調的頻率範圍從41.2 到42.1 GHz。在 1-MHz 位移處，量測所得到的相位雜訊為-105.5 dBc/Hz。此電路擁有低相位雜訊 及低功率消耗優點。 最後為一利用台積電0.18-μm互補式金氧半場效電晶體製程製作四相位振盪器之直接升頻正交調器。電路的主要架構是由兩組串聯耦合壓控振盪器及直接 升頻正交調器組成。此架構的優點是可方便計算四相位振盪器的振幅及相位誤 差。此電路具有1 GHz 的可調頻寬和在載波1-MHz 處其相位為-115 dBc/Hz 雜 訊。在偏壓為1.7 V時，核心電路消耗功率為5.1 mW。另外，此電路的振幅和 相位誤差分別為0.5 dBm 及3°。此四相位振盪器之直接升頻正交調器擁有低相 位雜訊及低功率消耗優點外，還具有低的優位指數(FOM)。
並列摘要
The low phase noise VCO is necessary in the modern communications systems, especially for the high-level digital modulation schemes, such as n-QAM and n-PSK modulation. Therefore, a low phase noise VCO is essential for the applications. The goal of the thesis is to design and implement low phase noise VCOs using GaAs HBT and CMOS technologies. The thesis was organized into three parts. An introduction was first summary to present the design and implement of the oscillators, and a Ku-band VCO is demonstrated in this part. The principle and advantages of the π-feedback oscillator is described, and the balanced π-feedback VCO is implemented by using 2-μm HBT process. Finally, the basics and application of the quadrature VCO with a reflection-type IQ modulator is presented and then the quadrature VCO with a reflection-type IQ modulator is implemented using a 0.18-μmCMOS process. The Ku-band VCO is designed and implemented using WIN Semiconductors 2-μmGaAs HBT technology. The frequency is from 14.6 to 16.6 GHz with a phase noise of -112.5 dBc/Hz. Besides, the VCO can provide a maximum output power of 6.9 dBm under core current of 12.5 mA from a 2 V supply. This VCO has the advantages of a low phase noise and wide tuning range. In addition, the Q-band VCO using balanced π-feedback is demonstrated in this thesis. With a core power consumption of 20 mW, the tuning range is from 41.2 to 42.1 GHz. The measured phase noise is -105.5 dBc/Hz at 1-MHz offset. This circuithas the advantages of low phase noise and low power consumption. Finally, the QVCO with a reflection-type IQ modulator using standard 0.18-mm bulk CMOS technology is presented. A serial-coupled QVCO and a reflection-type IQ modulator are combined in a single chip. The advantage of this configuration is easy evaluation of the amplitude and phase errors of the QVCO. The circuit achieves the tuning range of 1 GHz and the phase noise of -115 dBc/Hz at 1-MHz. The total power consumption is 5.1 mW with a dc supply voltage of 1.7 V. Moreover, the amplitude and phase errors of the QVCO are with in 0.5 dB and 3°, respectively. The QVCO with a reflection-type IQ modulator has the advantages of low phase noise, low power consumption and the lowest FOM.
參考文獻
延伸閱讀
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