Question

A transmission line terminates in two branches, each of length $\lambda /4$, as shown. The branches are terminated by $50\Omega$ loads. The lines are lossless and have characteristic impedances shown. Determine the impedance $Z_i$ as seen by the source.

Answer 1

Ans : (d)

$Z_1=\frac{Z_0^2}{Z_{L_1}}=\frac{(100{)}^2}{50}=200\Omega$

$Z_2=\frac{Z_0^2}{Z_2}=\frac{(100{)}^2}{50}=200\Omega$

$Z_L=Z_1\left|\right|Z_2=100\Omega$

$Z_i=\frac{Z_0^2}{Z_L}=\frac{(50{)}^2}{100}=25\Omega$