Farklı Mesafe ve Açılarda RF Yayılımına Maruz Kalan İnsan Kafasındaki Sıcaklık ve Özgül Soğurma Oranı Dağılımı

Year 2017, Volume: 9 Issue: 2, 92 - 102, 15.06.2017

Fulya Çallıalp Kunter Funda Cırık Acıkaya

https://doi.org/10.29137/umagd.352469

Abstract

Bu makale, insan kafası içerisinden elde edilen
özgül soğurma oranı (ÖSO) ve cep telefonlarındaki elektrik alan maruziyetinin
sebep olduğu ısıl etkileri sunmaktadır. 900 MHz ve 1800 MHz frekanslarında
yayınım yapan cep telefonları mikrostrip patch anten ile modellenmiş ve çıkış
güçleri olabilecek en kötü durum senaryosuna göre seçilmiştir. Sonlu elemanlar
yöntem (SEY) tabanlı COMSOL Multiphysics yazılım programı yardımıyla, kafa
modelindeki ÖSO ve sıcaklık dağılımları üzerinde, sadece anten ile kafa modeli
arasındaki mesafenin etkisi değil, aynı zamanda kafaya göre antenin açısının
etkisi de incelenmiştir. Çalışmada gösterilmiştir ki, antenin kafaya göre
mesafe ve açısının, kafadaki ÖSO değerleri ve sıcaklık artışında önemli bir
etkisi vardır. Benzetim sonucunda, ÖSO değerlerinin 900 MHz’de güvenlik sınır
değerlerinin altında iken 1800 MHz’de antenin kafadan olan uzaklığı 0,2 cm
olduğunda sınır değerlerinin altında olduğu bulunmuştur. Buna ek olarak,  kafadaki sıcaklık artışının diğer yapılan
çalışmalarla oldukça uyumlu olduğu not edilmiştir.

Keywords

Biyoısı Denklemi, Elektromanyetik Alan Maruziyeti, Sonlu Elemanlar Yöntemi, Özgül Soğurma Oranı

Temperature and Specific Absorption Rate Distribution in the Human Head Exposed to RF Propagation at Different Distances and Angles

Abstract

This paper presents specific absorption rate
(SAR) obtained inside a human head and the thermal effects due to exposure to a
cellular phone. The cellular phone radiating at 900 MHz and 1800 MHz
frequencies was modeled by microstrip patch antenna and its output power was
chosen according to the worst-case scenario. By the aid of finite element
method (FEM) based COMSOL Multiphysics software program, not only the effect of
distance between the antenna and the head model but also the effect of
antenna’s angle relative to the head on SAR and the temperature distribution in
the head model were investigated. It was shown in the study that the distance
and the angle of the antenna to the head had significant importance on the SAR
values and the temperature increase in the head. As a result of the simulation,
it was found that SAR values at 900 MHz were under the safety limit values
whereas at 1800 MHz were under the limits when the distance between the antenna
and the head was 0.2 cm. Furthermore, it was noted that the temperature
increase on the head was in good agreement with the other studies.

Keywords

Bioheat Equation, Electromagnetic Field Exposure, Finite Element Method, Specific Absorption Rate

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