Reactance Dependence of Radiation Efficiency and Impedance Matching of A Wrapped Loop Antenna

Instead of optimizing dimensions of an antenna, variable reactors are loaded on the antenna and the reactance values are optimized to achieve desired characteristics. The possibility of achieving both high radiation efficiency and good impedance matching is examined by visualizing the reactance regions where the characteristics are satisfied. Examination for a triple wrapped loop antenna shows that the reactance regions where impedance matching is good overlap the reactance regions where radiation efficiency is low when the antenna is electrically small. The influence of conductivity to the reactance regions is investigated with comparing the reactance regions with respect to input power and total radiated power.