A discussion on the quality factor of impedance matched electrically small wire antennas

The quality factors of several impedance matched, electrically small wire antennas are compared as a function of matching technique and antenna geometry. The antennas considered have the same height and wire diameter, and they are designed to be self-resonant at approximately the same frequency. The antennas are impedance matched to a nominal 50 Ohm characteristic impedance using either a parallel stub, lossless reactive network or lossless transformer. It is shown that the quality factors of the antennas are essentially the same, and for the most parts independent of the matching technique and differences in the antenna geometry. The quality factor of the impedance matched, electrically small antenna is primarily established by the antenna's height and effective volume.