高频连接器技术讲义.ppt

高頻連接器相關技術1.按工作频率：低频和高频视频：频率范围在3HZ30MHZ之间的无线电波 射频：频率范围在3千HZ3000GHZ之间的无线电波(Radio Frequency)Notes:1GHz=1,000MHz,1MHz=1,000,000Hz同軸射頻連接器范例二.高頻連接器,具備如下幾個特點:1-1特性阻抗(impendence):水管例子講解1-2插入损耗(insertion loss):对连接器的要求主要是插入损耗小，反射损耗高,插入损失是指由于连接器的引入而导致的链路功率损耗,定义为连接器的输出功率与输入功率比的分贝数.如图2,设输入功率为PI,输出功率为PO,.则此连接器的插入损耗为:连接器的基本性能 1-3电压驻波比（VSWR）（Voltage Standing Wave Voltage Standing Wave Ratio):Ratio):电压驻波比（VSWR）是射频技术中最常用的参数，用来衡量部件之间的匹配是否良好。电压驻波比用来表述端口的匹配性能的。同一性能还可用回波损耗来表述。这两个指标定义如下，电压驻波比：VSWR=(1+|r|)/(1-|r|)r：为发射系数=ZL-Z0/ZL+Z0 ZL为输入阻抗，Z0为理想阻抗回波损耗：RL=10log(入射功率/反射功率)1-4串扰（crosstalk）Ground and ground pin distributionPin lengthAggressor to victim pin distanceGround loopsImpedance mismatchesRise-time1-5传输延迟（delay）1-6时滞（skew）:时滞即时间延迟1-7 衰减:信号在通道中传输时，会随着传输距离的增加而逐渐变小,衰减(Attenuation)衰减是指信号幅度沿链路传输的减弱，是由于电缆的电阻所造成的电能损耗以及电缆绝缘材料所造成的电能泄漏，衰减以分 贝（db）表示，低的衰减值表示链路的性能好，而链路越长，频率越高，衰减就越大。试想一下，一个过分衰减的的信号，接收端 又怎能识别呢！SAS Connector,Complete Mechanical ModelArea of interestReceptacle SidePlug SideTo characterize the electrical performance of the SAS connector,the model only included the portion highlighted above.Electrical Analysis ModelThis figure shows the 9-pin model for the electrical simulation.Though the solder pads were included,this model does not include the effects of vias,ground,power planes and/or trace routing on the module and motherboard.Pin Designations:G G Tx+Tx-G Rx+Rx-G GPin#9Pin#1Differential Impedance 50ps(20-80%)91.8 Ohms108 OhmsSAS Specification Limits*SAS-1.1 Revision 0,10 July 2003Differential Propagation Delay 50ps111 psDifferential Cross Talk 50ps(20-80%)0.37%0.04%Impedance 250ps(20-80%)82.1 Ohms79.9 OhmsChanges done on the solder tail of the cable contact(Rev 1)improve impedance matching.However,the increased cable contact thickness(rev 2)proves to be of no consequence to the results.VSWR 1.25 GHzSimilar to the impedance results,this plots shows that electrically,Rev 1 and 2 are not distinct from each other.S-Parameters(S-ParametersS參數(S11、S21、S12、S22)