Question

In Isotropic radiation, which of the following vector component is absent in pointing vector?

(a) \(\widehat{a_r}\)

(b) \(\widehat{a_\theta}\)

(c) \(\widehat{a_\emptyset}\)

(d) Both \(\widehat{a_\theta} \,and\, \widehat{a_\emptyset} \)

The question was asked in an online interview.

My question is from Isotropic Radiators topic in section Antenna Parameters of Antennas

Answer 1

Right answer is (d) Both \(\widehat{a_\theta} \,and\, \widehat{a_\emptyset} \)

Explanation: Isotropic radiators will radiate power equally in all directions. Due to this symmetrical distribution, components of θ, Φ get cancelled. So it will have only radial component.