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With the increasing use of cell phones , the concern of the people on the phone electromagnetic radiation is getting closer and closer , phone electromagnetic radiation is also becoming increasingly important . As the use of mobile phones near the human head , the existence of potential harm to the human body , therefore , become an important topic of research study phone antenna radiation to the head and electromagnetic shielding antenna . Specific Absorption Rate or SAR is more recognized standards of measurement of electromagnetic radiation , but there is no uniform standard limits and expectations by this thesis provide data to support the unity of the SAR limit standards . This paper phone external antenna - monopole antenna , built-in antenna - planar inverted -F antenna electromagnetic simulation model to establish a three- sphere model head , using the finite-difference time-domain algorithm poll within specific absorption rate simulation study in the 900MHz , 1800MHz two frequencies from the head 1cm , 2cm , 3cm case specific absorption rate , and draw SAR maps . The two antennas in the same distance on the same frequency . Selected smaller radiation antenna PIFA electromagnetic shielding , this thesis only when 900MHz operating frequency , close to the poll 1cm case , analysis shield after the SAR , and draw corresponding SAR maps . SAR peak and the distribution of different cases , comparative analysis , the following conclusions : (a ) the same frequency from the head distance is also the same , PIFA antenna radiation on the human head than a monopole antenna is smaller . Such as a PIFA antenna at 900MHz, off poll 1cm , capitation per gram of tissue absorption SAR values ??to be smaller than when the monopole antenna is in the same circumstances . (B ) the PIFA antenna and the monopole antenna common rules : With the head of the radiation from the increase of the distance to succeed , the radiation reduction . (C) electromagnetic shielding PIFA SAR values ??are significantly reduced , the ability of radiation of different materials is different . Due to the limited time and personal knowledge of this topic is just a preliminary study of electromagnetic radiation , which provides the foundation for the future to continue to study .
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