Characteristic mode analysis of electrically large conformal bifilar helical antenna

A characteristic mode analysis of an electrically large bifilar helix is presented in this paper. Characteristic mode analysis is typically performed on electrically small to intermediate size antennas for simplicity. When the antenna becomes electrically large, there are many modes and it is difficult to identify the dominant modes. A procedure for determining the important characteristic modes is outlined in this paper and applied to a bifilar helix. The key features of the dominant modes making up the total current and pattern will be discussed.