2.13. The normalized radiation intensity radiated by an antenna is given by
U(θ, φ) = {
sin θ cos² φ, 0° ≤ θ ≤ 180°, 90° ≤ φ ≤ 270°
0, Elsewhere
The maximum of the radiation intensity occurs towards θ = 90° and φ = 180°. Find the:
(a) Exact maximum directivity (dimensionless and in dB).
(b) Half-power beamwidth (in degrees) in the principal azimuth (horizontal) plane.
(c) Half-power beamwidth (in degrees) in the principal elevation (vertical) plane.
(d) Maximum directivity (dimensionless and in dB) using an appropriate approximate method that you know. Indicate which one you are using.