多频段CMOS低噪声放大器LNA的研究与设计

【作者】 郑薇；

【导师】 李竞春；

【作者基本信息】 电子科技大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 目前各种无线通信标准的发展对射频集成电路（RFIC）提出了多模式、多频段的新要求，实现无线接收机中低噪声放大器（LNA）的多频段化成为射频集成电路的一个研究热点。本论文系统研究了并行式多频段LNA工作原理，并针对目前移动通信主流标准（GSM0.9GHz/DCS1.8GHz/PCS1.9GHz/TD-SCDMA2.0GHz），设计了一个并行式四频段低噪声放大器。首先分析了射频集成电路中无源器件的特性和MOSFET的高频噪声，阐述了无源RLC网络和用于阻抗变换的L型网络的基本工作原理。对多频段LNA的各种实现方法进行了总结及比较，并深入研究了能够同时工作在多个频段下的并行式LNA，包括其噪声匹配、输入阻抗匹配和输出阻抗匹配等，特别是针对输出网络需要同时满足阻抗匹配和增益的要求，提出了多频段输出网络的设计方法。接着深入研究了并行式多频段LNA中的各种非线性。除了常见的二次谐波、带内三阶交调点和带内1dB压缩点外，还分析了并行式LNA中当多种频段同时工作时所特有的带间n阶交调点和带间1dB压缩点等非线性。然后基于级联系统非线性理论，从电路结构的角度出发，对多频段LNA的线性度进行了研究并做出了相应的优化。最后基于TSMC0.35μm RF CMOS工艺，设计了一个并行式四频段LNA，针对具体频段的特点得到适当的优化方案。采用Cadence下的SpectreRF仿真器进行了调试和仿真，仿真结果表明在电源电压为1.8V，功耗16.2mW时，四个频段下噪声系数NF均小于3.2dB，功率增益S₂₁均大于10dB，输入输出匹配s₁₁和s₂₂均小于-10dB，带内和带间输入三阶交调点均大于0dBm，带内和带间1dB压缩点均优于-15dBm，各种指标均达到了要求。更多还原

【Abstract】 With the development and enrichment of various wireless communication standards, multi-band and multi-mode application requirements are brought to RFIC design. The realization of multi-band LNA in multi-band wireless receiver has become an important subject.The basic theory and crucial technology of concurrent multi-band LNA are studied in this thesis. A specific concurrent four-band （GSM0.9GHz/DCS1.8GHz/PCS1.9GHz/ TD-SCDMA2.0GHz） LNA is designed with the mobile communication standards.Firstly, the passive devices and noise of MOS transistors in RFIC, RLC network and L-transform used in impedance-transform are introduced and discussed. The concurrent multi-band LNA is researched in great details after comparing various realistic method and characteristics of multi-band LNA. The noise matching, input and output matching are included. Especially for the last one, a new multi-band output network design manner that fulfills both output matching and power gain requirement at the same time is presented.Secondly, the nonlinearity of concurrent multi-band LNA is studied and discussed in details. Besides the second-order harmonics, in-band IP3 and 1dB compression point in each band, cross-band nth-order intercept point IPn and cross-band 1dB compression point in concurrent LNA when multi-band works simultaneously are analyzed specifically. Then the cascode structure’s nonlinearity is discussed and optimized.Finally, a concurrent four-band LNA based on TSMC 0.35μm RF CMOS process is obtained after debugging and simulating with the simulator SpectreRF in Cadence. The results show with a voltage-supply of 1.8V and a power consumption of 16.2mW, NF in all the four bands is less than 3.2dB, power gain is more than 10dB, s₁₁ and s₂₂ are less than -10dB, in-band and cross-band IIP3 are more than 0dBm, in-band and cross-band P_1dB are more than -15dBm and all the performance meet the requirement.更多还原