Wideband Circularly Polarized Antennas for Wearable Internet of Medical Things Devices

This paper presents designs of circularly polarized antennas with wideband operation characteristics for wearable Internet of Medical Things Devices. The antennas are designed on textile substrates, which can be easily integrated into wearable devices. Additionally, their specific absorption rates (SARs) under US and European standards are below the safe level. The first design employs magneto-electric dipole antenna as a primary radiator to achieve wideband operation of 24.2% (5.02-6.4 GHz) with stable gain of around 6.6 dBi. For wider bandwidth, the second design employs four metasurface-based radiating elements arranged in a 2 × 2 configuration and excited by a sequential phase feeding network. The simulated operating bandwidth of the array is 53% (4.65-8.0 GHz) and maximum gain of 11.5 dBi.