Radiation-Based Figure of Merit for Environmental Sensitivity Analysis of Mobile Phone Antennas: A standard tool to evaluate different antenna solutions

The performance of mobile phone antennas is strongly dependent on their environment. However, in the literature, there is no standard criterion to judge this environmental sensitivity. In this work, first, an elaborate figure of merit (FOM) is introduced based on the radiation characteristics of antennas. Then, characteristic modes (CMs) are employed to provide another representation of this FOM. This technique is able to deliver an in-depth understanding of the effect of the environment on the radiating modes of an antenna, which are strongly related to the sensitivity. This perception opens the possibility for designers to achieve less-sensitive antennas. To demonstrate the applicability of the proposed FOM, it is applied to a range of mobile phone antennas available in the literature.