*Network Analysis
*Multiport Network
*Scattering [[Parameters]]*Impedance [[Parameters]]
*Smith Chart
|All versions|{{download|http://www.emagtech.com/downloads/ProjectRepo/RFLesson3.zip RF Lesson 3}} }}
=== What You Will Learn ===
In this tutorial you will run a network analysis test of the simple transmission line circuit you built in the previous tutorial lessons. You will examine the Z- and S-parameters of your circuit and study the Smith chart.
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[[File:RFTUT3_1.png|thumb|500pxleft|550px|The quarter-wave impedance transformer circuit tuned for f<sub>0</sub> = 2GHz.]]
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[[File:RFTUT3_2.png|thumb|left|230px|The "Connections" tab of Network Analysis Test Panel.]]
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[[File:RFTUT3_3.png|thumb|left|230px|The "Sweep" tab of Network Analysis Test Panel.]]
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[[File:RFTUT3_4.png|thumb|left|230px|The "Output" tab of Network Analysis Test Panel.]]
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[[File:RFTUT3_5.png|thumb|750pxleft|720px|Cartesian graph of the magnitude and phase of the S11-parameter.]]
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[[File:RFTUT3_6.png|thumb|230px|The "Connections" tab of Network Analysis Test Panel.]]Next, go back to the '''Output''' tab of the Network Analysis Test Panel and choose the '''Z''' radio button in the "Parameter Set" section. Make sure you remove the check mark from the "Decibels" check box. From the top "Graph Type" options, choose '''Cartesian (Real/Imag)''', because you are more interested in the frequency response of the real and imaginary parts of the Z11-parameter, which are indeed the input impedance of your circuit. Run another network analysis and view the output graph as shown below. Note that at 2GHz, the real part of the impedance is 50Ω and its imaginary part vanishes as you would expect for perfect impedance match.
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[[File:RFTUT3_6.png|thumb|left|230px|The "Connections" tab of Network Analysis Test Panel.]]</td></tr></table> Run another network analysis and view the output graph as shown below. Note that at 2GHz, the real part of the impedance is 50Ω and its imaginary part vanishes as you would expect for perfect impedance match. <table><tr><td>[[File:RFTUT3_8.png|thumb|750pxleft|720px|Cartesian graph of the real and imaginary parts of the Z11-parameter.]]
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[[File:RFTUT3 12.png|thumb|750pxleft|720px|The S11-parameter plotted on a Smith Chart. The tracking bar shows the points corresponding to 2GHz.]]
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[[File:RFTUT3 13.png|thumb|360pxleft|480px|Smith chart showing the variation of the S11-parameter with frequency at a fixed line length of 37.5mm.]]
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[[File:RFTUT3 14.png|thumb|360pxleft|480px|Smith chart showing the variation of the S11-parameter with line length at a fixed frequency of 2GHz.]]
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[[File:RFTUT3_15.png|thumb|500pxleft|550px|The quarter-wave impedance transformer circuit with an inductive load.]]
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[[File:RFTUT3_16.png|thumb|750pxleft|720px|Computed s11 data for line segment length L = 75mm and Z<sub>L</sub> = 100 + j80 Ω over the frequency range 1-5GHz.]]
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