Consider the 3 m long lossless air-filled transmission line shown in the figure. It has a characteristic impedance of $$120\pi \,\Omega $$, is terminated by a short circuit, and is excited with a frequency of 37.5 MHz. What is the nature of the input impedance $$({Z_{in}})$$?

In the transmission line shown, the impedance $${Z_{in}}$$ (in ohms) between node A and the ground is

For a parallel plate transmission line, let v be the speed of propagation and Z be the characteristic impedance. Neglecting fringe effects, a redution of the spacing between the plates by a factor of two results in

A transmission line with a characteristic impedance of 100 $$\Omega $$ is used to match a 50 $$\Omega $$ section to a 200 $$\Omega $$ section. If the matching is to be done both at 429 MHz and 1 GHz, the tength of the transmission line can be approximately