Question

Parasitic element that is typically about 5 percent longer than the half-wave dipole-driven element is called _______

(a) Array element

(b) Director element

(c) Reflector element

(d) Driven element

The question was posed to me in an online interview.

My question is from Types of Antenna topic in section Antennas and Wave Propagation of Avionics

Answer 1

Right option is (c) Reflector element

To elaborate: The reflector, a parasitic element that is typically about 5 percent longer than the half-wave dipole-driven element, is spaced from the driven element by a distance of 0.15λ to 0.25λ. When the signal radiated from the dipole reaches the reflector, it induces a voltage into the reflector and the reflector produces some radiation of its own creating a highly focused beam in the direction of the driven element.