An AM radio loop antenna is operated at 900 kHz and has the

An AM radio loop antenna is operated at 900 kHz and has the Thevenin equivalent circuit shown below. It is connected to a receiver having a 50 Ohm input impedance. How much power is delivered to the receiver? What receiver impedance would give maximum power transfer to the receiver? If the condition in (b) is met, how much power would be delivered?

Solution

a) p=(i)^2*Rl

p=[(10*10^-3)/(12+50+j900)]^2*50=6.14*10^-9<-172.118 watts.

b) maximum power is transferred when zl=conjugate of zs.

zl=(12-j900) ohms.

c) maximum power=i^2*Rl

i=v/(rs+rl)=(10*10^-3)/(12+12)=4.166*10^-4 ampss.

pmax=(4.166*10^-4)^2*12=2.08*10^-6 watts.