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InterviewSolution
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Assume two similar antennas for transmitting and receiving. If the operating frequency gets reduced by 3 times then the received power gets _______(a) increases by factor 3(b) decreases by factor 3(c) increases by factor 9(d) decreases by factor 9This question was posed to me in unit test.Query is from Friis Transmission Equation in chapter Antenna Parameters of Antennas |
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Answer» RIGHT answer is (C) increases by FACTOR 9 Explanation: From FRISS transmission equation, \(\frac{P_r}{P_t} = \frac{G_t G_r λ^2}{(4\pi R)^2} = \frac{G_t G_r c^2}{(4\pi Rf)^2}\) \(\frac{P_{r1}}{P_{r2}} = \frac{f_2^2}{f_1^2} = \frac{(f/3)^2}{f^2} = \frac{1}{9}\) Pr2=9Pr1 |
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