Study On Electromagnetic Compatibility(SAR&HAC) For Mobile Phone's Antenn

As technology advances, the mobile phone terminal has rapidly developed with a variety of brands and strong functions. Currently, increasing testing organizations abroad bring out more and more measurement indicators for mobile antenna's impact on human body. CTIA, the most authoritative and non-profit organization in communications industry in the world, firstly put forward some indexes of measuring mobile phones'antenna, including the measuring indexes of electromagnetic compatibility SAR and HAC. SAR is a ratio that measures human brain and body's absorption and consumption of electromagnetic power. HAC measures the electromagnetic interference produced by the mobile phone antenna to the people who wear the hearing aids. These are two important indexes at present that measure electromagnetic compatibility of mobile phone antennaThis paper firstly introduces mobile phones'passive and active electrical parameters. Passive electrical parameters include the input impedance, the direction factor, radiation efficiency, gain, polarization, and active electrical parameters are about the total radiated power TRP, total Isotropic sensitivity TIS, Specific Absorption Rate SAR, and Hearing Aid Compatibility HAC.SAR studies that human body will generate Induction Electromagnetic Field under the influence of external electromagnetic fields. Various organs of the body are lossy media, so internal Electromagnetic fields will generate current, causing to absorb and dissipate Electromagnetic energy .HAC discussed the electromagnetic compatibility index when mobile phone antenna works together with hearing aids. Because people wearing hearing aids often suffer from the interference of the electromagnetic fields between mobile phones and hearing aids when making a call, their communication quality is abnormally unclear. Then respectively take the example of the printed circuit antenna (PIFA) and Monopole antenna, their characteristics of SAR and HAC are introduced. At last, take the Alcatel mobile phone for example, it is elaborated that how to improve the performance of SAR and HAC through the methods of Aluminum paste ,open window, and antenna alignment adjustment ,making the index comply with the CTIA regulations.The influence of antenna on SAR and HAC is the peculiar requirement in wireless communication antenna. To work out a kind of antenna that not only satisfies communication, but also has good electromagnetic compatibility is a problem that mobile antenna must face. In this paper, put PIFA antenna as the research object, the method to improve the SAR / HAC is studied in detail, to provide the reference and instruction for designing antennas satisfying the Electromagnetic Compatibility.