Topic: Electromagnetics / Antennas
According to Friis Transmission Equation, the received power $P_r$ is directly proportional to:
- A. The square of the distance between antennas
- B. The square of wavelength
- C. The square of frequency
- D. The cube of the transmitted power
Answer: B. The square of wavelength
Explanation: The Friis Transmission Equation states $P_r = P_t G_t G_r \left(\frac{\lambda}{4\pi R}\right)^2$. Thus, the received power is directly proportional to the square of the wavelength ($\lambda^2$) and inversely proportional to the square of the distance ($R^2$) and the square of the frequency (since $\lambda = c/f$).