Array of the four arc monopoles on a sphere with surface impedance

The antenna array of four arc monopoles which are located parallel to the surface of a perfectly conducting or impedance sphere is considered. The influences of the phase of excitation of a monopole, the distance to the sphere surface, and sphere radius and its surface impedance on the directivity of the radiator are considered. It is shown that the radiation pattern of the antenna for antiphase excitation is highly directional and has a single maximum in the plane of arrangement of the monopoles. Also, the characteristics of such an antenna array on a hemisphere located on an infinite perfectly conducting screen are studied.