An antenna system and related method are disclosed for an electrically small antenna of variable geometry capable of a harmonically pure resonant radiation pattern over a broadband coverage of frequency selection. One geometrical embodiment comprises a multiple loop antenna system is configured to radiate a switched signal via the multiple antenna elements to inhibit transmission of any of the harmonics of the signal. An additional geometrical embodiment comprises a cylindrical shell with one or more interior center conductors to overcome radiation resistance and radiate a signal pattern of desirable toroidal shape free from undesirable harmonics.