【作者】 孙景业；

【导师】 林福江； 刁盛锡；

【作者基本信息】 中国科学技术大学 ， 电路与系统， 2014， 博士

【摘要】 无线通信市场近年来迅猛发展,各种无线设备给人们的生活提供了便利,在人们的生活中扮演着越来越重要的角色。生活中的各种无线通信协议的射频前端电路互不兼容,这给人们的便携化带来了不便。因此设计能够兼容多种无线通信协议的射频前端就成为了设计者们需要面对的问题,而多模多频带的宽带接收机又是需要攻克的重点和难点。本文分别对多模多频带的宽带接收机的核心模块进行了研究,并在此基础上研究完整的接收机电路。低噪声放大器(Low Noise Amplifier)是接收机链路的第一级电路,需要实现宽带范围内的输入匹配,并在功耗尽可能低的条件下得到低噪声和适当的增益。本文首次提出了一种正反馈环路用来改善因为隔直电容带来的低频增益和噪声的恶化。同时本文综合利用电流复用技术和电容交叉耦合技术来降低电路的功耗,采用电阻负反馈结构来提高输入匹配的带宽,同时分析了反馈电阻对于各个性能参数的影响从而获得了最优的噪声和增益。混频器(Mixer)是接收机链路的第二级电路,也是完成变频功能的核心模块。因为线性度的考虑,LNA的增益一般不会过大,因此混频器的噪声系数应该尽可能的低。本文在分析了跨导管和开关管对于混频器的噪声贡献后,采用了噪声抵消的技术来降低跨导管的噪声,同时采用电流抽取技术降低开关管的噪声。在综合分析了电流抽取技术对于增益、噪声的影响后选择了一个最佳的电流抽取比例。本文采用基于电流驱动无源混频器的架构来研究多模多频段的宽带接收机。在分析了传统的拓扑结构的优缺点后,本文提出了一种新的方法来提高无源混频器得到的交流电流比例。同时在分析了传统的跨阻放大器的缺点后,本文针对性的进行了改进,从而在功耗,噪声和稳定性等方面有了比较大的改善。所设计的电路使用SMIC65nm工艺流片,测试结果验证了设计思想。更多还原

【Abstract】 The wireless communication market has grown fast in the past few years. Different kinds of wireless handsets are playing an important role in our lives. However, RF front-ends of different communication systems are not compatible with each other, resulting in lack of portable. This problem pushes designers to design an RF front-end which is capable to deal with multiple standards. Of all the sub-systems, Multi-mode multi-band receiver is difficult for designers. We will study on the core modules of the multi-mode multi-band receiver, and after that we will study on the integrated receiver.Low noise amplifier is the first stage of the receiver. It should achieve wideband input matching and low noise figure with power consumption as low as possible. We apply the current reuse and capacitor cross coupling techniques to reduce the power consumption to one fourth, and we use the resistor feedback topology to get the wideband input matching. After analyzing the impact of the feedback resistor on the parameters, we get an optimized resistance for the best noise figure and other parameters.Mixer is the second stage in the receiver which plays a key role in the down conversion. For the sake of linearity, the gain of the LNA shouldn’t be too large. Then the noise figure of the mixer should be as low as possible. After analyzing the noise contribution of the transconductance stage and the switch stage, we apply the noise cancellation technique and the current bleeding technique to reduce the noise. Since the ratio of the current bleeding has a direct affection on the gain and noise figure of mixer, we optimized this ratio to get the best performance.This thesis applies the current driven passive mixer to design the multi-mode multi-band receiver. We proposed a new way to raise the ac current ratio of mixer to LNA and we also proposed a new architecture to implement the transimpedance amplifier after analyzing the drawbacks of the traditional transimpedance amplifier. The new architecture consumes a lower power and meanwhile, the nose figure and stability are better than the traditional competitors. Our work is implemented with SMIC65nm process. The measured results demonstrate our design strategies.更多还原