Miniaturised implantable circular polarized antenna with a high ARBW

Area of Science:

• Electromagnetics
• Biomedical Engineering
• Materials Science

Background:

• Implanted antennas are crucial for wireless biological applications.
• Achieving circular polarization and wide bandwidth in miniaturized antennas presents challenges.
• Metamaterials offer novel ways to enhance antenna performance.

Purpose of the Study:

• To design and evaluate a miniaturized, circularly polarized implanted antenna for biological applications operating in the 2.44 GHz ISM band.
• To investigate the performance enhancement using a sorting pin and an H-shaped metamaterial.
• To validate the antenna's performance using human skin-mimicking gel and compare simulation with measurement.

Main Methods:

• An implanted antenna was designed and loaded with a sorting pin and an H-shaped metamaterial.
• Resonant frequency, axial ratio bandwidth (ARBW), and specific absorption rate (SAR) were analyzed.
• Experimental validation was performed using a skin-mimicking gel at 2.44 GHz.

Main Results:

• The sorting pin reduced the resonant frequency and introduced circular polarization with a 580 MHz ARBW.
• Incorporating the H-shaped metamaterial resulted in strong CP behavior with an 830 MHz ARBW.
• The specific absorption rate was maintained at a reasonable value (952.1 W/KG).
• Experimental impedance bandwidths of 90 MHz (simulated 110 MHz) were achieved.

Conclusions:

• The proposed antenna demonstrates miniaturization, strong circular polarization, and wide bandwidth suitable for biological applications.
• The integration of metamaterials effectively enhances antenna performance.
• Simulation and measurement results are consistent, validating the antenna design.