射频电路与天线ppt

ResearchInstituteofRF&WirelessTechniques射频电路与天线RFCircuitsandAntenas第31讲复习谢泽明华南理工大学电子与信息学院射频与无线技术研究所TEL:22236201-801Email:[e-mail]&WirelessTechniquesSouthChinaUniversityofTechnology传输线理论公式：tantanLcinccLZjZlZZZjZlincincZZZZ22()LjljlLLlee1111熟练求解传输线问题：求阻抗、驻波比、反射系数maxmin11UU2()jzLUzeUcZ0lzLZUUIU射频电路与天线RFCircuitsandAntennas第一部分传输线理论ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology匹配传输线短路传输线开路传输线电抗负载行驻波状态ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology匹配传输线ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology短路传输线ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology开路传输线ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology行驻波状态ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology圆图的组成–导纳圆图•等反射系数圆•等电导圆•等电纳圆–阻抗圆图•等反射系数圆•等电阻圆•等电抗圆ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology2cckff传输条件为：=或2cck00ccTETMkf对于、波，，，具有高通特性00ccTEMkf对于波，，，无条件传输第二部分波导传输线ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology221c相位常数：21pcvv相速：21pc相波长：21gcvvv群速度：ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology21TEcZ21TMcZTEMZ波阻抗：ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology矩形波导2222ckmnabc截止波长：ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology矩形波导的主模——TE10波2222amnabc截止波长：ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology圆波导2cmnaTMP对波'2cmnaTEP对波ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology圆波导的三个主要模式TE11模特点：最低次模容易产生极化简并传输过程中会产生极化面偏转用于距离传输与矩形波导TE10模相近，用作矩形——圆形转换用作极化衰减器，波形转换器，环形器ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyTE01模的特点不是最低模损耗最低，频率升高，损耗下降轴对称，无极化简并做长距离传输电流无纵向分量，可作连接器件作高Q谐振腔TM11模简并ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyTE01模的特点不是最低模损耗最低，频率升高，损耗下降轴对称，无极化简并做长距离传输电流无纵向分量，可作连接器件,可作旋转关节作高Q谐振腔TM11模简并ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology同轴线截面有双导体，可传TEM波存在TE、TM波（高次模）工作在TEM模带状线ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology微带线微带线主模为准TEM模微带线有双导体，主模是TEM模。由于基片存在，存在不同媒质的分界面，单独TEM模不满足比边界条件，需同时存在TE、TM模。TE、TM模比TEM模小很多，场的纵向分量远小于横向分量，合成场分布近似TEM模，故为准TEM模。频率越低，越接近TEM模色散越小。频率越高，越偏离TEM模，色散越大。可工作到直流。微带线还存在高次模：波导模表面波模reccrepZZcv//01rerResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology激励与耦合：在传输线上建立所需工作模式的传输波激励的原则：为了有效激励或耦合出所需模式，激励或耦合装置在传输线上产生的电场磁场与所需模式的场相一致，产生的电流与所需模式相一致按原理分，激励和耦合可分为电激励：在传输线上产生所需电场磁激励：在传输线上产生所需磁场电磁激励：同时在传输线上产生所需电场与磁场按装置分，激励和耦合可分为探针激励：小环激励：小孔激励：ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology耦合线当两队传输线相互靠近时,彼此就会产生电磁耦合，这种传输线称为耦合传输线耦合带状线和耦合微带线常用来构造定向耦合器，滤波器等微波元件。对称的耦合线一般可以采用奇偶模法分析。ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology第三部分网络理论波导等效为平行双线)()(Re21zIzUP线1Re2ttSTPdsEH波zjeUzU0)(zjeIzI0)(TTHEZIUZ波导的磁场与平行双线的电流地位对应，波导的电场与平行双线的电压地位对应波导等效为平行双线后，等效电流为波导磁场的纵向分布函数，等效电压为波导电场的纵向分布函数(,)()tEexyUz(,)()tHhxyIzResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology1TttSehds称归一化条件CZUU归一化电压CZII归一化电流ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyZ矩阵–阻抗矩阵Z1I2I1U2U1T2T2CZ1CZ211211111212002222212100IIIIUUZZIIUUZZIIResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyY矩阵－导纳矩阵Y1I2I1U2U1T2T1cY2cY22212122121111UYUYIUYUYIUYI211211111212002222212100UUUUIIYYUUIIYZUUResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyA矩阵－转移矩阵A1I2I1U2U1T2T2CZ1CZ22222112122111IAUAIIAUAU2211IUAIU021210212202112021112222IUUIUIAIIAIUAUUAResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyS矩阵——散射参数用端口的入射波计算端口的反射波（出射波）1a2a3ana1b2b3bnb123nSnnnnnnnnaaaSSSSSSSSSbbb2121222211121121kikCkkrkCkaUZbUZ—归一化电压进波—归一化电压出波aSb)(0jiabSjaiiii)(0jiabSiajiij其他口匹配时i口的反射系数其他口匹配时j口到i口的传输系数Zck为第k口的特性阻抗ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyT矩阵——传输参数用端口2的进出波计算端口1的进出波T1a2a1b2b22222112122111aTbTbaTbTa2211abTbaResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology双口网络的工作特性参量衰减工作衰减插入衰减插入反射系数、插入驻波比电压传输系数插入相移ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnology第四部分射频元器件ResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyResearchInstituteofRF&WirelessTechniquesSouthChinaUniversityofTechnologyResearchInstituteofRF&WirelessTechni