A 100- lossless transmission line is connected to a second line of 40- impedance, whose length is λ/4. The other end of the short line is terminated by a 25-Ω resistor. A sinusoidal wave (of frequency f) having 50 W average power is incident from the 100-Ω line.

(a) Evaluate the input impedance to the quarter-wave line.

(b) Determine the steady-state power that is dissipated by the resistor.

(c) Now suppose that the operating frequency is lowered to one-half its original value. Determine the new input impedance, Z'_in, for this case.

(d) For the new frequency, calculate the power in watts that returns to the input end of the line after reflection.