Question

Friss transfer formula is given by _____

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

(b) \(P_r = P_t G_r G_t (\frac{λ}{4πR})\)

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

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

I had been asked this question at a job interview.

My question is based upon Measurement of Gain in division Modern Antennas & Antenna Measurements of Antennas

Answer 1

The correct answer is (a) \(P_r = P_t G_r G_t (\frac{λ}{4πR})^2 \)

To explain: Friss transmission is basis for the absolute gain measurement. The Friss transfer equation is given by \(P_r = P_t G_r G_t (\frac{λ}{4πR})^2 \,where\, G_r,G_t \) are the gains of receiving and transmitting antenna respectively.