Question

Which of the following is the condition for the normal mode of radiation?

(a) The dimensions of antenna must be smaller compared to the wavelength

(b) The dimensions of antenna must be approximately equal to the wavelength

(c) The dimensions of antenna must be greater compared to the wavelength

(d) The dimensions of antenna must be approximately equal to or greater than the wavelength

This question was posed to me during an online interview.

I want to ask this question from Frequency Independent Antenna topic in chapter Frequency Independent Antenna of Antennas

Answer 1

The correct option is (a) The dimensions of antenna must be smaller compared to the wavelength

Easiest explanation: In normal mode, the radiation is normal to the axis of the antenna hence it is broadside directed. The dimensions of the antenna are small compared to the wavelength in normal mode. In axial mode, it is approximately equal to the wavelength. In conical mode, it is greater than wavelength.