Antenna Design Considerations for Low SAR Mobile Terminals

In this chapter, a detailed examination of the notion of coupling modification using two antennas appropriate to contemporary smartphone devices in talk position for voice conversations is presented. They can significantly lower the specific absorption rate (SAR) while maintaining efficiency owing to power splitting and a reasonable amount of inter element coupling by adopting the optimal relative phase between the components. When the antenna components are not in the talk position, they may still be utilized for multiple‐input, multiple‐output (MIMO) without significantly decreasing their basic capacity limit, but this is secondary. Where the ground plane has an appropriate form factor, the idea might be used to frequency ranges utilized in mobile communications ranging from 1.8 to 6 GHz. Extensive simulations are performed utilizing two planar inverted‐F antennas (PIFAs) operating at 2.4 GHz to illustrate conceptually how two antennas may be adjusted to lower SAR by more than 50% when compared with a single antenna element. No matter how the user holds the device in the talk position or the user's head structure, the SAR reduction is maintained. Antenna prototypes are measured and compared with validate capacity while utilizing two MIMO terminal antennas away from the body.