A Loop Loading Technique for the Miniaturization of Non-Planar and Planar Antennas

A size reduction technique of non-planar and planar antennas using a self-resonant topology is highlighted. The antennas considered are the dipole, the monopole and the slot radiator. The dipole below its resonant frequency is known to possess a capacitive reactance. It is shown that the inductive reactance of a loop can be used to match a below-resonant dipole similar to the inductive load offered by a metamaterial shell. The configuration reduces the resonant frequency of the dipole by 26.01%, causing the dipole to almost reach the electrically small limit. Despite the loaded dipole touching the electrically small limit, the antenna needs no matching networks, offers a high efficiency and exhibits a bandwidth better than the unperturbed dipole. The radiation pattern is also seen to be unaffected by the presence of the loops. The concept is also demonstrated for the size-reduction of a monopole and for a planar slot.