Topic: Antennas and Wave Propagation
The directivity of a prime-focal parabolic reflector antenna is 30 dBi. If the efficiency of the antenna is 50%, the gain of the antenna is:
- A. 27 dBi
- B. 33 dBi
- C. 25 dBi
- D. 80 dBi
Answer: A. 27 dBi
Explanation: Directivity D = 30 dBi, efficiency n = 0.5 (-3 dB). Antenna gain = Directivity + efficiency(dB) = 30 - 3 = 27 dB.