Radiation efficiency optimization of electrically small antennas: Application to 3D folded dipole

This paper deals with the radiation efficiency optimization of Electrically Small Antennas (ESAs). Based on the well-known tradeoff between antenna maximum dimensions, Q-factor and radiation efficiency, several authors focused on minimizing the Q-factor for a given antenna size in order to increase its bandwidth. For some applications (Wireless Sensor Network), only a narrow bandwidth is needed and the radiation efficiency is a crucial parameter to shrink the required power. Thus, this paper presents the radiation efficiency optimization of 3D folded dipole antennas for a given size. First, we compare different folding topologies and then we study the effect of the wire diameter and the material on the ESAs performances.