高頻連接器技術(shù)講義.ppt

1、高頻連接器相關(guān)技術(shù),一.相關(guān)概念 二.高頻連接器的特點(diǎn) 三.高頻連接器的性能 四.設(shè)計(jì)流程及範(fàn)例,1.按工作頻率：低頻和高頻,視頻：頻率范圍在3HZ30MHZ之間的無(wú)線電波,射頻：頻率范圍在3千HZ3000GHZ之間的無(wú)線電波 (Radio Frequency),一.高頻及其他相關(guān)概念,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(gè)特點(diǎn):,1-1特性阻抗(impendence):水管例子講解 1-2插入損耗(insertion loss):對(duì)連接器的要求主要是插入損耗小，反射損耗高,插入損失是指由于連接器的引入而導(dǎo)致

2、的鏈路功率損耗,定義為連接器的輸出功率與輸入功率比的分貝數(shù).如圖2,設(shè)輸入功率為PI, 輸出功率為PO,.則此連接器的插入損耗為:,三.高頻/射頻連接器的基本性能,1-3電壓駐波比（VSWR）（Voltage Standing Wave Ratio):電壓駐波比（VSWR）是射頻技術(shù)中最常用的參數(shù)，用來(lái)衡量部件之間的匹配是否良好。 電壓駐波比用來(lái)表述端口的匹配性能的。同一性能還可用回波損耗來(lái)表述。這兩個(gè)指標(biāo)定義如下，電壓駐波比： VSWR=(1+|r|)/(1-|r|) r ：為發(fā)射系數(shù) =ZL-Z0/ZL+Z0 ZL為輸入阻抗，Z0為理想阻抗回波損耗： RL=10log(入射功率/反射功率)

3、 1-4串?dāng)_（crosstalk） Ground and ground pin distribution Pin length Aggressor to victim pin distance Ground loops Impedance mismatches Rise-time,1-5傳輸延遲（delay） 1-6時(shí)滯（skew）:時(shí)滯即時(shí)間延遲 1-7 衰減:信號(hào)在通道中傳輸時(shí)，會(huì)隨著傳輸距離的增加而逐漸變小,衰減 (Attenuation)衰減是指信號(hào)幅度沿鏈路傳輸?shù)臏p弱，是由于電纜的電阻所造成的電能損耗以及電纜絕緣材料所造成的電能泄漏，衰減以分 貝（db）表示，低的衰減值表示鏈路的性能

4、好，而鏈路越長(zhǎng)，頻率越高，衰減就越大。試想一下，一個(gè)過分衰減的的信號(hào)，接收端 又怎能識(shí)別呢！,四.設(shè)計(jì)相關(guān)技術(shù)與流程,SAS Connector, Complete Mechanical Model,Area of interest,Receptacle Side,Plug Side,To characterize the electrical performance of the SAS connector, the model only included the portion highlighted above.,Electrical Analysis Model,This figure

5、 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 G,Pin #9,Pin #1,Differential Impedance 50ps

6、(20-80%),91.8 Ohms,108 Ohms,SAS Specification Limits*,*SAS-1.1 Revision 0, 10 July 2003,Differential Propagation Delay 50ps,111 ps,Differential Cross Talk 50ps (20-80%),0.37 %,0.04 %,Impedance 250ps (20-80%),82.1 Ohms,79.9 Ohms,Changes 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 GHz,1.18,1.12,Similar to the impedance results, this plots shows that e