Question

Problem 5 An antenna with a load impedance Z. = (73 + j42.5) 2 is connected to a transmitter through a 50- 2 lossless transmission line. If under matched conditions (50-22 load) the transmitter can deliver 10 W to the load, how much power can it deliver to the antenna? Assume that Ze=Zo.

Answer 1

ERO 30 ! 3=(73+54215) Transmission line Antenna transmitter When Ze=30 = The transmitter can deliver 10 W to the load. se, it transmits maximum power ( 5507 sen Pin = 10 4. Prel=10ht Iner den Pin = input power Pdela power delivered to load 2242 Pin = Pdell : 550, No reflections] {= 20 - - Z-7, 13 / 4 - 9 23 15 4 : Retro 720, 3+juars to 123 +54215 = 23+5425 1 1 233525 -48.3 20.371. | 123 45 4251 51 6935 25 30 When 2520 - Poel = maximum (550) When 7452. Sto, so only part of the incident power input power delivered to load

of power reflected - In 18100/= 01137 2100 -13-74. T% power delivered to load - C-15112100 = (1-01134] X100 = 863.76 amount The amount of power delivered to load is given by = 86.3-4. of (total transmitted] I power p a 86-30%. (201) power deliver = 863 8 8-6.3 Watts to Load 100 1= 20 => power delivered to load = 10 hatte 12L72 power delivered to load = 8.63 Walt V Mismatched Condition
so the power that the transmitter can deliver to antenna is 8.63 Watts when load impedance is NOT equal to characteristic impedance of transmission line .