标题: | 射频压控震荡器使用多重静电驱动电极之微机械式可变电容 An RF VCO with Micromachined Tunable Capacitor Using Multiple Electrostatic Driving Electrodes |
作者: | 苏煜仁 Yu-Jen Su 邱俊诚 陈永平 Jin-Chern Chiou Yon-Ping Chen 电控工程研究所 |
关键字: | 压控震荡器;可变电容;CMOS-MEMS;射频;VCO;Tunable Capacitor;CMOS-MEMS;RF |
公开日期: | 2002 |
摘要: | 摘要 本篇论文提出了一应用于射频压控震荡器之以CMOS-MEMS制程的线性可变电容。根据静电力学与弹力学的延伸可得到控制电压与电容之非线性关系。使用多重静电驱动电极,藉由改变极板之数目可得到电容之工作区间,亦可得到压控震荡器频率变化之工作区间。因此,藉由此工作区间,可使用线性控制设计之演算法来决定电压所加之极板的数目与次序。 现代的无线通讯系统中,锁相回路在射频前端扮演相当重要的角色。而以锁相回路为基础的频率合成器中,最重要的部分即为压控震荡器。传统如电容电感式的压控震荡器,具非线性控制电压对频率变化之问题。使用多重静电驱动电极可变电容之CMOS-MEMS压控震荡器提供一不使用线性化电路而可电压线性控制震荡之解决方案。再者,机械改变方式可避免掉高损耗,并且使用空气介质取代其他介电材料可使电容之Q值提高,因而改善压控震荡器之相位杂讯。 Abstract In this thesis, a linearly tunable capacitor applied to radio frequency (RF) voltage-controlled oscillator using CMOS-MEMS process is proposed. According to the extension of electrostatic theory and elastic theory, the nonlinear relationship between capacitances and applied voltages is obtained. Using multiple electrostatic driving electrodes, the working space of capacitor can be obtained by varying the number of electrodes, so as the frequency tuning range of the voltage-controlled oscillator. Hence, with those working spaces, a linear control design algorithm can be used to determine the number and the order of multiple electrodes that the control voltage is applied to. Phase-locked loop (PLL) plays an important role in RF front-ends of the modern wireless communication systems. Voltage-controlled oscillator (VCO) is the main part of phase-locked loop based frequency synthesizers. Conventional VCO such as the LC-tank VCO has the problem of nonlinear frequency tuning range versus control voltage. A CMOS-MEMS VCO with tunable capacitor that uses multiple electrostatic driving electrodes offers a solution for linear voltage-controlled oscillation without a linearization circuit. Furthermore, mechanical tuning avoids high losses and the use of air gap instead of other dielectric materials makes high-Q capacitors possible. Hence, the phase noise of VCO can also be improved. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#NT910591079 http://hdl.handle.net/11536/71054 |
显示于类别: | Thesis |