Question

For aperture antenna to be efficient and have high directivity, its area should be ____________

(a) ≥ λ^2

(b) ≥ 1/λ

(c) ≤ λ^2

(d) ≤ λ

This question was addressed to me at a job interview.

My enquiry is from Uniform Aperture Field in section Aperture Antenna of Antennas

Answer 1

Correct choice is (a) ≥ λ^2

To elaborate: Antenna with an aperture at the end is known as aperture antenna. Example is waveguide. For aperture antenna to have high directivity its area should be ≥ λ^2. These antennas usually operated at UHF and above frequencies.