一种智能传感器射频前端的低功耗设计与实现  

Design and Implementation of Low Power RF Front End Applied in Intelligent Sensor

作　　者：田晓明[1] 白春风[1] 吴建辉[1] 

机构地区：[1]东南大学国家专用集成电路系统工程技术研究中心,南京210096

出　　处：《传感技术学报》2014年第10期1326-1331,共6页Chinese Journal of Sensors and Actuators

摘　　要：叙述了一种应用于智能传感器的低功耗射频前端电路,包括低噪声放大器和下混频器。智能传感器的无线通信一般基于Zigbee协议,Zigbee接收机一般采用低中频的架构以获得灵敏度和低功耗之间较好的折中。主要研究了从提高晶体管跨导效率和提高电流利用效率两个角度实现低功耗的方法,低噪声放大器采用交叉耦合输入的噪声抵消结构,增强了输入管的等效跨导,因而在较低功耗代价下获得了低噪声系数并实现50Ω阻抗匹配;下混频器采用基于电流放大器的无源混频结构,输入跨导级通过电流复用提高了电流利用效率而输出跨阻级引入跨导增强技术减少了中频电流的泄漏,这使得在同等功耗水平下可以获得更高的线性度,即节省了功耗。讨论了电路设计过程并在TSMC 0.13μm CMOS射频工艺下进行流片验证,在1.2 V电压下整个前端电路消耗5.4 mW功耗和0.12 mm2芯片面积,仿真结果表明低噪声放大器获得了2.1 dB的噪声系数和小于-30 dB的S11,混频器转换增益为27.7 dB;而芯片测试得到的前端噪声系数为5.4 dB,IIP3达到5.5 dBm,能够满足智能传感器无线通信的需要。A low power RF front end,which includes low noise amplifier( LNA) and down mixer,is employed in an intelligent sensor. The wireless communications of intelligent sensors are based on Zigbee protocol,and a Zigbee re￣ceiver generally uses low IF architechture to obtain a good trade￣off between high sensivity and low power. Proposed LNA adopts a common gate(CG)noise cancelation structure and employs‘gm boost’technique to achieve a low noise figure( NF) for a low power consumption and a simplified impedance matching net. Passive architechture is employed in the design of down mixer with both the input transconductance stage and the output transimpedance stage reducing power consumption by employing‘gm boost’ technique. Besides,passive mixing switch consumes no quiescent current,which also contribute to the low power design. The design is implemented in TSMC 0. 13 μm CMOS RF technology with the circuit consuming 0.12 mm2 active area and 5.4 mW power at the supply of 1.2 V. Simulation results reveal that LNA achieves a performance of 2.1 dB NF and S11 below -30 dB,as well as the mixer obtains 27.7 dB conversion gain. What’s more,5.4 dB NF and 5.5 dBm IIP3 is measured in the test of RF front end,which is competent for intelligent sensor applications.

关 键 词：智能传感器 低功耗射频前端 噪声抵消 跨导增强 无源混频器 

分 类 号：TN942[电子电信—信号与信息处理]