Question

Complex dielectric constant of earth is given by ____

(a) \(ϵ’=ϵ+\frac{σ}{jw} \)

(b) \(ϵ’=σϵ+\frac{1}{jw} \)

(c) \(ϵ’=σ+\frac{ϵ}{jw} \)

(d) \(ϵ’=ϵ+\frac{σϵ}{jw} \)

This question was addressed to me in a national level competition.

I'm obligated to ask this question of Radio Wave Propagation in division Radio Wave Propagation of Antennas

Answer 1

Correct choice is (a) \(ϵ’=ϵ+\frac{σ}{jw} \)

The explanation is: The earth is neither a good conductor nor a good dielectric. So the dielectric constant of earth is complex and is given by  \(ϵ’=ϵ+\frac{σ}{jw} \)where σ is the conductivity and w is angular frequency.