Question

Relation between Antenna gain G and directivity D is ______

(a) G = ∈r D

(b) G = ∈r/D

(c) G = D/∈r

(d) G = 1/∈rD

The question was posed to me by my school principal while I was bunking the class.

My question is from Measurement of Gain topic in division Modern Antennas & Antenna Measurements of Antennas

Answer 1

The correct answer is (a) G = ∈r D

For explanation: Antenna gain refers to the amount of radiation intensity in the desired direction to that of would have radiated when the isotropic antenna radiates. The relation between Antenna gain and Directivity is G = ∈r D, ∈r is the antenna efficiency.