Dual-Band Textile C-Shape Complementary Split-Ring Metamaterial MIMO Antenna for Remote Health Monitoring

Background: Remote Health Monitoring Systems (RHMSs) rely on wearable antennas to enable the reliable wireless transmission of physiological data. However, existing wearable Multiple-Input Multiple-Output (MIMO) antennas often suffer from low gain and limited isolation, particularly under flexible and on-body conditions. Methods: This study proposes a dual-band textile C-shaped Complementary Split-Ring (CSR) Metamaterial (MTM)-based MIMO antenna operating at 2.45 GHz and 3.5 GHz. A metasurface layer composed of a 3 × 5 CSR array is integrated beneath the radiating elements to enhance isolation and realized gain. The antenna is evaluated under flat and bending conditions, and on-body performance is validated through Specific Absorption Rate (SAR) and Received Signal Strength Indicator (RSSI) measurements. Results: The proposed antenna achieves measured Mutual Coupling (MC) lower than −30 dB and realized gains of 2.45 dBi and 6.43 dBi at 2.45 GHz and 3.5 GHz, respectively. SAR values remain well below international safety limits, and RSSI measurements confirm improved communication performance over distances up to 10 m. Conclusion: The proposed dual-band textile metamaterial MIMO antenna provides a safe, flexible, and high-performance solution for wearable RHMS applications.