GATE EC 2016 Set 2 Q54 — Transmission Lines

A microwave circuit consisting of lossless transmission lines $T_{1}$ and $T_{2}$ is shown in the figure. The plot shows the magnitude of the input reflection coefficient $\Gamma$ as a function of frequency $f$. The phase velocity of the signal in the transmission lines is $2\times 10^{8}$ $m/s$.

The length $L$ (in meters) of $T_{2}$ is _________