SAR reduction using a single SRR superstrate for a dual-band antenna

Area of Science:

• Electromagnetics
• Antenna Engineering
• Biomedical Engineering

Background:

• Dual-band antennas are crucial for mobile communication systems like GSM.
• Ensuring human safety by minimizing Specific Absorption Rate (SAR) is a key design consideration for antennas used near the head.

Purpose of the Study:

• To design and analyze a dual-band microstrip antenna operating at 900 and 1800 MHz.
• To investigate the effectiveness of a split ring resonator (SRR) superstrate in reducing the specific absorption rate (SAR) of the antenna when used near a human head.
• To validate simulation results with fabricated prototype measurements.

Main Methods:

• Design of a dual-band microstrip antenna for GSM 900/1800 MHz.
• Integration of a single split ring resonator (SRR) as a superstrate above the antenna.
• Analysis of electromagnetic coupling and resonance within the SRR.
• Simulation of antenna performance and SAR reduction using a human head phantom.
• Fabrication and measurement of the antenna with SRR superstrate for return loss and radiation pattern.

Main Results:

• The SRR superstrate induced resonances at 0.9 and 1.8 GHz, enhancing antenna performance.
• Significant reduction in specific absorption rate (SAR) was achieved for a human head model at both operating frequencies.
• Measured return loss and radiation patterns closely matched simulation predictions.
• The SRR superstrate demonstrated effective control over electromagnetic fields, leading to SAR mitigation.

Conclusions:

• The proposed dual-band antenna with an SRR superstrate effectively reduces human head SAR at GSM 900/1800 MHz.
• The SRR acts as a parasitic element, influencing the antenna's electromagnetic field distribution to lower SAR.
• This design offers a promising solution for developing safer mobile communication antennas.