Question

If the operating frequency increases, powers received by the receiving antenna ______

(a) will decrease

(b) will Increase

(c) is Independent of frequency

(d) is not predictable

The question was posed to me during an internship interview.

Origin of the question is Friis Transmission Equation in portion Antenna Parameters of Antennas

Answer 1

Right choice is (a) will decrease

The best explanation: From the Friss transmission equation, the received power depends on the wavelength which is inversely proportional to the frequency. So the power decreases as the frequency increases.

\(\frac{P_r}{P_t} = \frac{G_t G_r λ^2}{(4πR)^2} = \frac{G_t G_r c^2}{(4πRf)^2} \)