纳米尺度CMOS工艺下智能射频前端关键技术研究

With the evolution of various wireless communication standards, smart devices are required to accommodate multiple communication protocols. The implementation of a flexible and low-cost RF front end is under urgent demand. Nowadays, existing multi-band multi-mode RF transceivers almost all adopt off-chip surface acoustic wave (SAW) filters with different center frequencies and bandwidth controlled by switch array, at the price of high area and component cost. Under the concept of holistic design, this research aims at achieving a reconfigurable, fully-integrated smart RF receiver. Utilizing the latest technique of filtering by aliasing (FA), the filter proposed in this scheme is able to adjust its bandwidth, center frequency, stopband rejection to accommodate various signal bands. Therefore, the problem of mutual interference among coexisting communication protocols might be mitigated and all components are integrated on one chip for low cost. This research is supposed to have good perspectives for both theoretical analysis and practical applications. The verified solutions of circuits and system can be commercialized in the future and obtain maximized economic and social value.

随着无线通信标准的演变、无线通信设备多频段多模式需求的增长，市场亟需高灵活性及低成本的射频前端方案。工业界方案多采用开关控制中心频率不同的多个声表面滤波器，需要承受较高成本。基于此，本研究通过理论分析和流片验证，应用混叠滤波技术，在全局设计的理念下，提出全新的全集成可重构的智能射频接收机，实现前端射频滤波器能够根据需要任意改变中心频率、带宽、阻带抑制比等性能，以解决多标准通信协议共存和互相干扰的难题，并使得所有元件均能集成在同一个芯片上，极大降低了成本。本研究提出并验证的电路与系统可以用于产业化，能够带来很好的经济效益和社会效益。

随着无线通信技术的长期演进，越来越多的通信标准开始占据有限的频谱资源。为了兼容多个频段和多个模式通信的需求，希望接收机的射频前端滤波器能够根据需要调节中心频率、带宽、增益等参数，因此需要低成本、高灵活性的信号收发方案。基于这些需求，本项目开展了对高性能收发机中射频前端可集成带通滤波技术的研究。应用周期性时变滤波技术，提出了全集成可重构的射频接收机前端的电路结构。.本项目首先总结现有周期性时变系统的分析方法，然后从混叠滤波技术和开关电容N路滤波技术的相同点出发，建立了二者统一的数学模型，并提出了具有谐波抑制功能的N路滤波技术。随后，本项目研究了基于负反馈放大器的N路滤波器原型并对其性能进行了仿真验证。针对其噪声问题，本项目提出了基于低噪声跨导放大器的谐波抑制N路滤波器电路结构，并给出了一种辅助校准技术以校准误差。最后，本项目在40nm CMOS工艺下设计了一款基于混叠滤波技术的接收机并进行了流片测试。所设计的接收机可以实现80.32dB的增益，-0.6dBm的IIP3，-10.5dBm的P1dB，6.27dB的噪声系数。