specific absorption rate(sar) reduction using ebg structures

Project Supervisor: : Dr. Shahid Bashir

Department of Electrical Engineering , University of Engineering & Technology, Peshawar

Syed Muhammad Bilal (10PWELE3806)Riaz ul Amin (10PWELE3799)Imran Ullah Khan (10PWELE3800)Abdirisak Mohamud (10PWELE3884)

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IntroductionProblem StatementProposed SolutionResearch MethodologyProposed DesignResultsConclusion

Progress in 3G and 4G technologyDevelopment in Smart phonesProlong exposure to harmful radiationsCauses heating effect in human tissue especially brain

Reducing the harmful effect is the need of present dayGlobally , a parameter known as Specific Absorption Rate (SAR)SAR is defined as the power absorbed per mass of tissue and has unit of watts/kgAim of our project is to reduce the SAR value

Radiations from portabledevices produce heatin human body

Strong need to reduce thisharmful effect

Using EBGs reduces the harmful effect by blocking the flow of surface wavesEBGs acts as LC circuit

A square patch antenna for 3.5GHZ band (WIMAX applications) has been designed.

Maximum dimensions of antenna are 45mm ×45mmDesign and simulation in CST

Proposed EBG has unit cell size of 10mm×10mmWith vias at the center

modified from conventional mushroom EBG to reduce unit cell sizeCross slots are used

Conventional EBG unit cell size for this band is 12mm×12mmSize reduction of 2mm has been obtained

A total of 12 unit cells are placed around the patchFor best coupling the distance between patch and EBG cells is 1mm

Antenna without EBG

Return loss plot is shownA gain of 4.54dbi

SAR calculation of antenna without EBGThe Cylinder with properties of human skin is placed at distance of 10mm (1 cm)Peak SAR value is 0.135 watts/kg

SAR calculation of antenna with EBGSame 10mm distance Peak SAR value is 0.058W/kgReduction of 57%

Remarkable SAR reduction by 57%EBG unit cell size reduction by 2mmImprovement in matching of antenna

EBGs are very effective in SAR reductionEBG unit cell size is large for low frequency applications EBG degrade certain antenna parameters

Proposed EBG has degraded the antenna gain and centralized frequencyFurther improvement can be made in this regard

Readers can download our thesis from here.http://topgravity.com/fyp-specific-absorption-rate-reduction-using-ebg-structures/