Evaluation of Specific Absorption Rate of Electromagnetic Radiation on Six Layer Human Brain Model - Microstrip Patch Antenna

Abstract

This paper presents the evaluation of specific absorption rate for human head by designing rectangular shaped microstrip patch antenna. An antenna is a transducer that converts electrical signals into EM waves and radiates into space. The performance of an antenna is measured by its parameters namely bandwidth, gain, return loss etc. There are several types of antennas available but the microstrip patch antennas are widely used for many applications because of its low profile, light weight, low cost, feed-line flexibility, versatility, ease of fabrication etc. Even though it has several advantages, it suffers from major drawbacks namely narrow bandwidth, low gain and high return loss. In order to overcome these drawbacks, FR-4 materials are used. Specific absorption rate (SAR) is a measurement of certain amount of radiation absorbed by human body while entering into an electromagnetic field. It is defined as the power absorbed per mass of tissue and has units of a watt per kilogram. SAR is typically averaged either over the complete body or over a small sample volume (typically 1g or 10g of tissue). For evaluating the antenna performance, gain, VSWR and the return loss were calculated for the proposed antenna and the proposed antenna provides the peak the gain of 4.43dB at 10.846GHz. The proposed antenna also provides the SAR value of 0.00109W/Kg is evaluated for 1g of tissue as per the IEEE standard. The human head model and the proposed antennas are designed using CST (Computer Simulation Technology) microwave studio tool.