A Wideband Monoconical Antenna for Airborne Applications With a Null-Filled Radiation Pattern

A wideband monoconical antenna with a null-filled radiation pattern for airborne applications is presented. A rotating current distribution, which radiates an electric field at the null point (
θ
=
φ
= 0°) of an omnidirectional radiation pattern of a conventional monoconical antenna, is formed using the proposed slotted structure in a monoconical radiator. In the proposed design, the null point is effectively filled over the 1:12 impedance-matched frequencies, while the size of the reference monoconical antenna is maintained. A figure of merit composed of the electric field intensity in the main radiation area (0° ≤
θ
≤ 45° and 0° ≤
φ
≤ 360°) and the profile of the antenna shows that the proposed antenna performs better than a conventional monoconical antenna or a fan-dipole antenna used in airborne applications. The impedance and radiation performances of the proposed antenna are verified experimentally from a 5.85:1 scaled built prototype.