Design of a Highly Miniaturized, Inherently Matched, Spherical Folded Dipole Antenna and Evaluation of Its Quality Factor

A highly miniaturized 3-D spherical folded dipole antenna has been reported, for which inherent impedance matching is achieved with respect to a practical source by employing simple series– $LC$ loading combination, thereby engineering its input impedance. In order maximize bandwidth, the employs helix structure as arm that occupies full volume of corresponding Chu sphere. bifilar (two arms) and quadrifilar (four loaded are designed, full-wave simulations show both resulting antennas demonstrate excellent when 85% in comparison resonant operating at same frequency. Despite high degree miniaturization, radiation efficiencies found be 87.1% 90.6%, respectively. Furthermore, various quality-factor definitions explored antenna, it observed quality factor around 1.83 (1.22) times predicted (Thal) lower bound.