SAR Reduction With Antenna Cluster Technique

An efficient and straightforward antenna design method is presented that maximizes the ratio of total efficiency and specific absorption rate (SAR). This goal is achieved with a multiport antenna cluster technique where several ports are excited collectively with appropriate feeding weights. These weights are found as an eigenvalue solution formulated in terms of the radiated and near-field power of an antenna. The method relies on both the near-field (SAR) and far-field (radiation) physics of an antenna and it can be applied to various design cases. The importance of the maximization of total-efficiency-SAR ratio and the feasibility of the proposed approach are demonstrated with a simple multiple-dipole antenna example and with a more realistic antenna design where a metal-rimmed antenna is held in the user’s hand.