Minimum radiation Q for spheroids – extension to cylinder, comparison to spherical formulas and practical antennas AP-S international symposium

The radiation Q (Qι) of an antenna is defined to be the antenna Q when the only loss is radiated power. It is well known that electrically small antennas have large radiation Q. Large Qr results in narrow bandwidth, reduced efficiency due to losses in tuning elements and high near fields, as well as high voltages and currents that limit the amount of radiated power. For each of these considerations it is important to minimize Qr of an ESA.