Module 5.4 Generator and Load Mismatches
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Reflection coefficient of the generator,
\(\Gamma_{G}\) =
Reflection coefficient of the load,
\(\Gamma_{L}\) =
Voltage standing wave ratio on the line,
\(SWR\) =
Input reflection coefficient at the generator,
\(\Gamma_{IN}\) =
Output reflection coefficient at the load,
\(\Gamma_{OUT}\) =
The power delivered to the load
\({\rm P}=\frac{1}{2} \left|V_{G} \right|^{2} \frac{R_{IN} }{(R_{IN} +R_{G} )^{2} +(X_{IN} +X_{G} )^{2}}=\) (mW)
The power delivered to the input terminal
\({\rm P}_{{\rm IN}} =\frac{1}{2} \left|\frac{V_{G} \sqrt{Z_{0} } }{Z_{G} +Z_{0} } \right|^{2} \frac{1-\left|\Gamma _{IN} \right|^{2} }{\left|1-\Gamma _{G} \Gamma _{IN} \right|^{2}}=\) (mW)
The power available from the generator
\({\rm P}_{{\rm AVS}} =\frac{1}{2} \left|\frac{V_{G} \sqrt{Z_{0} } }{Z_{G} +Z_{0} } \right|^{2} \frac{1}{1-\left|\Gamma _{G} \right|^{2}}=\) (mW)
The power available from the network
\({\rm P}_{{\rm AVN}} =\frac{1}{2} \left|\frac{V_{G} \sqrt{Z_{0} } }{Z_{G} +Z_{0} } \right|^{2} \frac{\left|1-\Gamma _{OUT} \Gamma _{L} \right|^{2} }{\left|1-\Gamma _{G} \Gamma _{L} \right|^{2} (1-\left|\Gamma _{OUT} \right|^{2} )}=\) (mW)

Introduction:

  In this module, we discuss the generator and load mismatch effects on the standing wave pattern and power distribution of a lossless transmission line. By adjusting the range sliders, you can observe the dynamic behavior of the standing wave and the variation of the average power delivered to the load.
  Ex.1:When the generator and the load impedances are both matched to the line ( \(Z_G = Z_L = Z_0\) ), the maximum power delivered to the load is obtained.
  Ex.2:When the generator impedance is matched to the line ( \(Z_G = Z_0\) ),, the average power available from the source (PAVS) reaches its maximum.

Parameters:

1. \(V_{G}\) : Generator voltage, (V)
2. \(Z_{G}\) : Generator impedance, (Ω)
3. \(Z_{L}\) : Load impedance, (Ω)
4. \(Z_{0}\) : Characteristic impedance of the transmission line, (Ω)
5. \(\beta\) : Phase constant, (rad/m)
6. \(f\) : Operating frequency, (GHz)
7. \(d\) : Length of the transmission line, (cm)