Question

Which of the following represents the relation between maximum power gain and maximum directivity gain of the antenna?

(a) Gpmax = ηrGdmax

(b) Gpmax = ηr/Gdmax

(c) ηr = \(\sqrt{(G_{pmax} G_{dmax})}\)

(d) ηr = \(\frac{G_{dmax}+G_{pmax}}{G_{dmax}-G_{pmax}}\)

The question was asked in an international level competition.

I need to ask this question from Power Gain in chapter Antenna Parameters of Antennas

Answer 1

The correct answer is (a) Gpmax = ηrGdmax

The explanation is: Maximum power gain is obtained when there are no ohmic losses. Gpmax=\(\frac{U_{max}}{P_{in}/4π}\)

Maximum directive gain  Gdmax=\(\frac{U_{max}}{P_r/4π}\, and\, \eta_r=\frac{P_r}{P_{in}}\)

∴Gpmax=ηr Gdmax