Basic Engineering Circuit Analysis 11th Edition by David Irwin ,Robert Nelms

تمرين 80

A cell phone antenna picks up a call. If the antenna and cell phone are modeled as shown in Fig. P5.129,
(a) Find R cell for maximum output power.
(b) Determine the value of P out.
(c) Determine the corresponding value of P ant.
(d) Find V o / V ant.
(e) Determine the amount of power lost in R ant.
(f) Calculate the efficiency = P out / P ant.
(g) Determine the value of R cell such that the efficiency is 90%.
(h) Given the change in (g), what is the new value of P ant
(i) Given the change in (g), what is the new value of P out
(j) Comment on the results obtained in (i) and (b).

Figure P5.129