SOLVED Numerical's - Antenna Theory - Page 2.




3) A certain antenna with an efficiency of 95% has maximum radiation intensity of 0.5 W/sr. Calculate its directivity when
(a) The input power is 0.4 W
(b) The radiated power is 0.3 W

SOLUTION:

a)

Prad = ηr Pin = (0.95) (0.4) = 0.38




4) Evaluate the directivity of an antenna with normalized radiation intensity



SOLUTION:




5) Determine the maximum effective area of a Hertzian dipole of length 10 cm operating at 10 MHz. If the antenna receives 3 µW of power, what is the power density of the incident wave?
SOLUTION:



For the hertzian dipole,

Gd = 1.5 sin2 θ




By definition, Pr = Ae Pave


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