可调谐N通道带通滤波器的设计  

Design of tunable N-path band-pass filter

作　　者：刘国伦 将品群 宋树祥[1] 岑明灿 谢丽娜 LIU Guolun;JIANG Pinqun;SONG Shuxiang;CEN Mingcan;XIE Lina(College of Electronic Engineering,Guangxi Normal University,Guilin 541004,Guangxi Zhuang Autonomous Region,China)

机构地区：[1]广西师范大学电子工程学院,广西桂林541004

出　　处：《电子元件与材料》2019年第2期82-87,共6页Electronic Components And Materials

基　　金：国家自然科学基金(61361011);广西自然科学基金(2017GXNSFAA198363);广西中青年教师基础能力提升项目(2019)

摘　　要：为了解决传统滤波器的中心频率不易调节、Q值低、带外抑制差和增益小等问题。本文设计了一种可调谐高Q值的增益提高型N通道带通滤波器,采用两路N通道差分结构和两个跨导放大器构成。差分结构消除偶次谐波,跨导放大器提高电路增益,片外变压器用作平衡-不平衡转换器,改善滤波器Q值并实现阻抗匹配。该滤波器在1.2 V供电电压下,采用TSMC 180 nm CMOS工艺,取N=4构成差分4通道滤波器。Cadence Spectre RF仿真结果显示,滤波器的增益大于8.5dB,中心频率可调范围为0.1～1 GHz,带内插入损耗S_(11)大于10 dB,带外IIP3大于10 dBm,噪声系数小于2.2 dB,在f_s=300 MHz处,带外抑制达到28 dB。该滤波器的高Q值、高可调谐和高性能使其在认知无线领域有着广泛的应用。Tranditional filters usually suffer the problems of low Q value,low gain,poor out-of-band suppression and hard to adjust their center frenquency,etc.In order to solve these problems,this paper presented a tunable high-Q gain-enhanced N-channel band-pass filter,which was composed by two N-channel differential structures and two transconductance amplifiers.The differential structures were used to eliminate the even harmonics and the transconductance amplifiers increased the gain of the filers.Besides,a off-chip transformer was applied as a balun to improve the Q value of the filter and achieve impedance matching.The filter was designed by using TSMC 180 nm CMOS process with N=4 to form a differential 4-channel filter.The supply voltage of the filter was 1.2V.The Cadence Spectre RF simulation results show that the filter achieves>8.5 dB gain,>10 dB in-band insertion loss(S11),>10 dBm the out-of-band IIP3 and<2.2 dB NF.The center frequency can be adjusted from 0.1 GHz to 1 GHz and at fs=300 MHz,the out-of-band rejection can reach 28 dB.The filter's excellent performance in high Q and high tunability can make it widely used in the field of cognitive wireless.

关 键 词：中心频率 带外抑制 增益提高 带通滤波器 可调谐 高性能 

分 类 号：TN713[电子电信—电路与系统]