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1、中華大學 通訊系,1,The Principle of Smith Chart,中華大學 通訊系 田慶誠 tienchu.edu.tw 03 5186030,中華大學 通訊系,2,RF工程師的算盤(ZY) Smith Chart,Z Chart (Red),Y Chart (Green),你會心算嗎?,電路分析速度快嗎?,中華大學 通訊系,3,Reflection Coefficient Gin Smith Chart,Gr,Gi,|G|=0.45,qG=63.4,反射係數以極座標讀取,G=1 Z= Open Circuit,G=0 Z=Z0 Matched Circuit,G=-1 Z=0
2、Short Circuit,中華大學 通訊系,4,Z0=Reference impedance z= Normalized impedance r= Normalized resistance x= Normalized reactance,Impedance, Z v.s. Voltage Reflection Coefficient, G,中華大學 通訊系,5,Impedance Plane andSmith (Z) Chart,Devised by P. H. Smith, January 1939.,r,+jx,-jx,r=1,x=1,x=-1,x=-1,x=1,r=1,x=0,r=0
3、,r=0,z=0,z=0,x=0,中華大學 通訊系,6,Constant Resistance r Circles,G=1 r= Open Circuit,G=0 r=1 Matched Circuit,G=-1 r=0 Short Circuit,G=-1/3,G=-2/3,G=1/3,G=2/3,r=0,r=1/5,r=1/2,r=1,r=2,r=5,中華大學 通訊系,7,Constant Reactance x Circles,x=0,x=0.5,x=1.0,x=2.0,x=-0.5,x=-1.0,x=-2.0,x0 Inductive Load,x0 Capacitive Load,x
4、=0 Resistive Load,中華大學 通訊系,8,G v.s. Z in Smith Chart,x=1.0,r=1,z=1+j1,G=0.4563.4,Z Chart in G plane,中華大學 通訊系,9,Y0=Reference admittance y= Normalized admittance g= Normalized conductance b= Normalized susceptance,Admittance, Y v.s. Voltage Reflection Coefficient, G,中華大學 通訊系,10,Admittance Plane andSmi
5、th (Y) Chart,Devised by P. H. Smith, January 1939.,g,+jb,-jb,g=1,b=1,b=-1,b=0,g=0,g=0,b=-1,b=1,g=1,g=0,y=0,b=0,中華大學 通訊系,11,Constant Conductance g Circles,G=1 g=0 Open Circuit,G=0 g=1 Matched Circuit,G=-1 g= Short Circuit,G=-1/3,G=-2/3,G=1/3,G=2/3,g=5,g=2,g=1,g=1/2,g=1/5,g=0,中華大學 通訊系,12,Constant Susceptance b Circles,b=0,b=-2.0,b=-1.0,b=-0.5,b=2.0,b=1.0,b=0.5,b0 Capacitive Load,b=0 Resistive Load,中華大學 通訊系,13,G v.s. Y in Smith Chart,b=-0.5,g=0.5,y=0.5-j0.5,G=0.4563.4,Y Chart in G plane,中華大學 通訊系,14,VSWR Circles in Smith Chart,VSWR2.0 |G|1/3,