GATE 2020 EC – Question 31
A transmission line of length $3\lambda/4$ and having a characteristic impedance of $50\ \Omega$ is terminated with a load of $400\ \Omega$. The impedance (rounded off to two decimal places) seen at the input end of the transmission line is ________ $\Omega$.
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Correct answer: 6.22 to 6.28
Explanation
A line of length $\frac{3\lambda}{4}$ (an odd number of quarter waves) acts as a quarter-wave transformer, so $Z_{in}=\frac{Z_0^2}{Z_L}=\frac{50^2}{400}=6.25\ \Omega$.