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Published byHarold Wilkerson Modified over 9 years ago
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Passive Devices (3 port network) S-matrix of 3 port networks (1) All ports are matched and network is reciprocal (2) can be lossless? 3 Port Network can not be lossless, reciprocal, and match at all port
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Matched, lossless, and nonreciprocal 3 port network Circulator
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Reciprocal, matched, and lossy 3 port network Reciprocal, lossless, and only 2 ports matched Port 3 is isolated Lossy power divider
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Passive Devices (4 port network) S-matrix of reciprocal and matched network For lossless, S-matrix must be unitary matrix
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Hybrid Coupler(3 dB Coupler)
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Even-Odd Mode Circuit Analysis If circuit can be decomposed into the superposition of an even-mode excitation and odd- mode excitation Adding two sets( even & odd) of excitations produces the original excitation
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3-Port Network: Power Divider (1)Reciprocal and Lossless -> some ports mismatched Lossless Power Divider: Input Admittance at Input Port for Input Port Matching, B=0 and Port #1 Port #2 Port #3 Ex) 1:2 divider (with B=0 & Port #1 matched: ) Reflection at Port #2 : Reflection at Port #3:
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(2)Resistive Divider – All ports are matched - output ports are not isolated
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Wilkinson Power Divider( equal power division) Resistive divider -all ports are matched -out-ports are isolated Microstrip Wilkinson Power Divider Equivalent Circuit
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Wilkinson Power Divider even mode odd mode Equivalent Circuit in normalized and symmetric form
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Wilkinson Power Divider: even mode Voltage on transmission line
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Wilkinson Power Divider: odd mode All power from Port #2 is delivered to r/2 resister, and all dissipated No power is delivered to Port #1
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Wilkinson Power Divider: input port Wilkinson Power Divider: S-matrix All ports are matched Reciprocal Lossy Output ports are isolated Symmetric Not Unitary
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Wilkinson Power Divider: unequal power division Wilkinson Power Divider: N-way Divider
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4-Port Network: Quadrature Hybrid 3 dB Directional Coupler with Quadrature Phase Difference between two output ports Reciprocal, Lossless, and all ports are matched.
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Even-mode
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Odd-mode
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Coupled Line Theory Propagating Modes on Symmetric Coupled Line Even ModeOdd Mode ground
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Even Mode Line Characteristics for even mode propagation Capacitance per unit length w/o dielectrics: Inductance per unit length: Capacitance per unit length with dielectrics: Characteristic Impedance: Propagation Constant:
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Odd Mode Line Characteristics for even mode propagation Capacitance per unit length w/o dielectrics: Inductance per unit length: Capacitance per unit length with dielectrics: Characteristic Impedance: Propagation Constant:
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(1)Voltage and Current Waves of Even Mode Excitation
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(1)Voltage and Current Waves of Odd Mode Excitation
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Voltage and Current Waves on Coupled Lines (1)Voltage and Current Waves on Line #1(2)Voltage and Current Waves on Line #2
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Impedance Matrix Z 11 = Z 22 =Z 33 = Z 44
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Impedance Matrix Z 12 =Z 21 =Z 34 =Z 43
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Impedance Matrix Z 13 = Z 31 = Z 24 = Z 42
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Impedance Matrix Z 14 = Z 41 = Z 32 = Z 23
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4-Port Network: Coupled Line Coupler
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Single Section Coupled Line Coupler Boundary Condition at each Port
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