Radiation field consideration of biconical horn antenna with different flare angles

The radiation fields of a biconical horn antenna with different flare angles are computed from both the fields of an equivalent Huygens source on the spherical-surface aperture and the infinite biconical horn antenna with spherical transverse electromagnetic wave. Numerical data and experimental results are first presented for the symmetrical biconical horn antenna ka=1.57 and 3.14 (where k is the propagation constant and a=cone length) with equal flare angle. Curves of the beamwidth versus cone length are then given for various flare angles. At flare angles above 75°, the beamwidth increases with the cone length, while at flare angles below about 75°, the beamwidth decreases with the cone length in this region of ka. For the asymmetrical biconical horn antenna, with two different flare angles (including a conical coaxial type and a discone type), the numerical and the experimental patterns are both presented. For the asymmetrical biconical horn antenna, the pattern main lobe direction, with respect to the antenna axis, may be adjusted by using suitable flare angles