The ground plane of wireless handheld devices plays a significant role in the electromagnetic behavior determining bandwidth, efficiency, and radiation patterns. Therefore, it is necessary to determine the frequency region where the ground plane can be better excited, especially for low frequencies where the performance of the radiating system is critical due to size limitations with respect to the operating wavelength. A fast method based on the radar cross section (RCS) is presented for computing the frequency at which the ground plane can be excited. The proposal is applied to three typical wireless platforms: a handset phone, a smartphone, and a clamshell phone. The method is compared with characteristic mode analysis and the results demonstrate a very good agreement in the resonant frequency prediction. Complex platforms using metallic strips and slots in the ground plane are analyzed using RCS which gives physical insight into the electromagnetic performance.
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