In this paper, the dual-frequency square loop loaded by a short-circuited coaxial stub is analyzed. The input impedance and the resonance frequency were obtained by analysis using the moment method. As a result, the operation and the effect of the loaded element of a short-circuited coaxial stub were clarified. Practical design parameters to optimize the antenna size and the dual frequency property of the square loop antenna loaded by a short-circuited coaxial stub are presented.
