Flexible UWB circular polarized six-port MIMO antenna for internet of medical things-based smart belts

Abstract The present study presents a six-port multiple-input and multiple-output (MIMO) antenna developed to meet the diversity requirements of body-centered communication in the Internet of Medical Things (IoMT)-based smart belts. The proposed antenna consists of six identical elements having a coplanar waveguide (CPW) structure. The antenna has a small profile area of 36 × 42 mm and a height of 0.76 mm with the careful placement of its elements. There are circular patches and a CPW feed structure at the center of the antenna. The ground-patch distance was set intuitively by considering the mutual coupling effect. The effect of the current distribution was increased, and a wide operating range was achieved by adding symmetrical circular slots to soil surfaces. As a proof of configuration, the simulation results are supported by a mesh network equivalent circuit model. The proposed antenna has a bandwidth of 177% in the 0.9–15 GHz frequency range at −6 dB reference. Moreover, it also has an omnidirectional radiation pattern and circular polarization. The peak gain value was found to be 7.8 dBi and the efficiency value to be approximately 90%. ECC, DG, TARC, and CCL parameter measurements were analyzed for performance evaluation of MIMO antennas. In addition, bending tests are also examined. The specific absorption rate (SAR) of the proposed antenna in tissues is evaluated by using infrared thermography. The results indicate that the SAR values are lower than international standards. The antenna design is specifically optimized to exhibit robust behavior when worn by an individual.