基于先进CMOS工艺的1-30GHz超宽带N-path滤波器研究

随着5G无线通信技术的飞速发展，毫米波频段由于其频谱宽、速率高等优点，受到了越来越多的关注。射频滤波器是射频收发前端的重要构成部分，具有对带外频率进行抑制、对系统的群时延进行改善等方面的重要作用。设计体积小、性能高、适合多频段的超宽带滤波器是研究的重点和难点。N-path 滤波器具有射频中心频率可调节、品质因数高、低功耗等优势，能为多协议收发机系统提供解决方案。本项目拟采用先进CMOS工艺实现超宽带1-30GHz N-path滤波器芯片。针对超宽带滤波器芯片需要宽带正交时钟的问题，采用CML分频器和高精度正交耦合器电路实现1-30GHz的正交信号，采用新型分布式低噪声放大器克服毫米波频段晶体管增益随频率变化导致增益平坦度差的问题。本项目研究频率覆盖1-30GHz，且实现窄带滤波的N-path滤波器芯片，性能达到国际前沿水平。

With the rapid development of 5G communication technology and wireless communication technology, Millimeter-wave band has attracted more and more attention because of its wide spectrum and high speed. RF filter is an important part of RF transceiver front-end, which plays an important role in suppressing out of band frequency and reducing group delay of the system. At the same time, the design of small size, high performance, suitable for multi-band ultra-wideband filter is the focus and difficulty of research, and the reconfigurable filter which can cover multiple bands is the front of research directions. This project plans to use advanced CMOS technology to realize UWB 1-30GHz N-path filter chip. N-path filter has the advantages of adjustable RF center frequency, high quality factor and low power consumption, which can provide solutions for multi-protocol transceiver systems. In view of the ultra-wideband filter chip design, the clock circuit covers a wide frequency range. A wideband CML frequency divider and high-precision quadrature coupler circuit are used to realize 1-30GHz quadrature signal. A new distributed low noise amplifier is used to overcome the problem that the gain of the transistor in millimeter wave band changes with the frequency, which leads to the deterioration of the enhancement level. This project studies the N-path filter chip with 1-30GHz frequency coverage and narrow-band filtering, and it has widest bandwidth compared to recent published papers.