Metasurface-Inspired Flexible Wearable MIMO Antenna Array for Wireless Body Area Network Applications and Biomedical Telemetry Devices

Abstract

This article presents a sub-6GHz ISM-band flexible wearable MIMO antenna array for wireless body area networks (WBANs) and biomedical telemetry devices. The array is based on metasurface inspired technology. The antenna array consists of 2×2 matrix of triangular-shaped radiation elements that were realized on 0.8 mm thick Rogers RT/duroid 5880 substrate. Radiation characteristics of the array are enhanced by isolating the surface current interaction between the individual radiators in the array. This is achieved by inserting an electromagnetic bandgap (EBG) decoupling structure between the radiating elements. The radiating elements were transformed into a metasurface by etching sub-wavelength slots inside them. The periodic arrangement of slots acts like resonant scatterers that manipulate the electromagnetic response of the surface. Results confirm that by employing the decoupling structure and sub-wavelength slots the isolation between the radiators is significantly improved (>34.8 dB). Moreover, there is an improvement in the array's fractional bandwidth, gain and the radiation efficiency. The optimized array design for operation over 5.0-6.6 GHz has an average gain and efficiency of 10 dBi and 83%, respectively. Results show that the array's performance is not greatly affected by a certain amount of bending. In fact, the antenna maintains a gain between 8.65-10.5 dBi and the efficiency between 77-83%. The proposed MIMO antenna array is relatively compact, can be easily fabricated on one side of a dielectric material, allows easy integration with RF circuitry, is robust, and maintains its characteristics with some bending. These features make it suitable for various wearable applications and biomedical telemetry devices.INDEX TERMS On-body antennas, wearable antennas, flexible antennas, metasurface (MTS) antennas, electromagnetic bandgap (EBG) devices, biomedical telemetry devices, wireless body area network (WBAN), MIMO antenna array.

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“…The designed antenna has the smallest profile height unlike the research reported in Musa and colleagues. [5][6][7][8][9][11][12][13][14][15] Extreme thinness can provide maximum conformability. Hence the reported antenna has good profile height reduction.…”

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“…Comparison of Characteristics Among Three Lenses in the near field of the structure to regulate electromagnetic waves in the far field (Althuwayb, 2022;Althuwayb et al, 2023;Le et al, 2020). The diffraction property exhibited by metasurfaces plays a significant role in their ability to manipulate electromagnetic waves (Chou, et al, 2018;Yang et al, 2018).…”

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