An approach to hybridisation of the Method of Moments (MoM) and the Finite Difference Time Domain (FDTD) method is investigated. This hybrid method is capable of analysing a system of multiple discrete regions by employing the principle of equivalent sources to excite their coupling surfaces. Examples are provided to indicate both the potential and limitations of the hybrid method. It is shown that this technique has the great advantage of accurately modelling complex and arbitrarily oriented mobile telephone handset antennas, especially typical helical types, in the proximity of a detailed...