Combined RIS and EBG Surfaces Inspired Meta-Wearable Textile MIMO Antenna Using Viscose-Wool Felt

Area of Science:

• Electromagnetic engineering
• Materials science
• Wearable technology

Background:

• Multiple-input-multiple-output (MIMO) antennas face challenges in maintaining gain while reducing mutual coupling.
• Textile antennas require innovative designs for improved performance and wearability.
• Metamaterials offer unique electromagnetic properties for antenna enhancement.

Purpose of the Study:

• To design and validate a textile MIMO antenna integrated with a reactive impedance surface (RIS) and electromagnetic bandgap (EBG).
• To improve antenna gain, bandwidth, and reduce mutual coupling for wearable microwave applications.
• To assess the antenna's performance under bending conditions and ensure human safety.

Main Methods:

• A rectangular RIS was designed as a reflector to enhance gain and bandwidth.
• A split-ring resonator (SRR) backed by a strip-line EBG was employed to minimize mutual coupling.
• Bending analysis and prototype fabrication were conducted to validate performance.
• Specific Absorption Rate (SAR) analysis was performed to evaluate human safety.

Main Results:

• The RIS improved antenna gain by 1.29 dBi and bandwidth by 170 MHz at 2.45 GHz.
• The EBG provided a bandgap from 2.37 GHz to 2.63 GHz, reducing mutual coupling (S21 < -40 dB).
• Bending conditions had minimal impact on antenna S-parameters.
• SAR values were below regulated limits, indicating safety for human use.

Conclusions:

• The proposed textile MIMO antenna with RIS and EBG demonstrates significant improvements in gain and mutual coupling reduction.
• The design is robust under bending, suitable for wearable microwave applications.
• The antenna meets safety standards, showing potential for practical implementation in wearable devices.