This paper presents a generic review of various methods performed to acquire a low SAR for antennas used in different applications. While the SAR is minimized, various parameters such as bandwidth, gain, directivity, efficiency, and antenna size are also taken into consideration. However, it has not been possible so far to achieve desirable results for all these parameters together, so the SAR limitations include an imbalance between one or more parameters that differ depending on the technique used to reduce the SAR.
Different techniques are used in SAR reduction like reflectors, RF shielding using Metamaterials, AMC, EBG, or by designing a directive antenna. Each of these types has its advantages and disadvantages that distinguish it from other types and determine the appropriate application for the use of this type.
This paper highlights the most common SAR reduction techniques and investigates the differences between them to make it easy for the researcher to select the proper type for each application.