An Enhanced Circularly Polarized Textile Antenna Using a Metasurface and Slot-Patterned Ground for Off-Body...

Area of Science:

• Electromagnetics and Antennas
• Wearable Technology
• Metamaterials

Background:

• Off-body communication systems require antennas with robust circularly polarized (CP) radiation.
• Existing textile antennas often struggle with bandwidth, gain, and performance under bending.
• Metasurfaces (MS) and slot-patterned grounds (SPG) offer potential for antenna performance enhancement.

Purpose of the Study:

• To present an enhanced CP all-textile antenna for 5.8 GHz ISM-band applications.
• To investigate the combined effect of MS and SPG on antenna performance, including bandwidth, gain, and radiation efficiency.
• To evaluate the antenna's performance in free space, near a human body, and under bending conditions.

Main Methods:

• A 3x3 metasurface (MS) was designed to convert linearly polarized (LP) waves to CP.
• A slot-patterned ground (SPG) with corner-truncated slots was employed to enhance axial ratio bandwidth (ARBW).
• The antenna was fabricated using conductive textile and felt, simulated under bending, and measured in free space and a human body environment.

Main Results:

• The proposed antenna achieved a measured impedance bandwidth (IBW) of 36.3% and ARBW of 18%.
• A peak gain of 6.39 dBic and radiation efficiency of 64.7% were recorded.
• Simulated specific absorption rate (SAR) satisfied US and EU safety standards, and bending simulations showed minimal performance degradation.

Conclusions:

• The novel combination of MS and SPG effectively generates and enhances CP characteristics for textile antennas.
• The proposed antenna offers significant improvements in IBW, gain, and radiation efficiency for wearable applications.
• The antenna demonstrates robust performance and safety compliance for off-body communication systems.