Chapter 10, Problem 10.16P

A $100-\Omega$ lossless transmission line is connected to a second line of $40-\Omega$ impedance, whose length is $\lambda /4$. The other end of the short line is terminated by a $25-\Omega$ resistor. A sinusoidal wave (of frequency f) having 50 W average power is incident from the $100-\Omega$ 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, $Z_{\text{in}}\text{'}$, for this case. (d) For the new frequency, calculate the power in watts that returns to the input end of the line after reflection.