Design of an aperture coupled MIMO antenna for on-body communication and performance enhancement with dielectric back reflector

Compact antennas with robust on-body performance are achieving more interest for wearable sensor nodes. In this paper, a modified aperture coupled multiple input multiple output (MIMO) antenna operating at 2.45 GHz industrial scientific and medical (ISM) band is presented for wearable devices. 8-shaped radiator with L-shaped ground slot is used to miniaturize the antenna dimensions. A dielectric reflector is added below the antenna to reduce the back radiations towards the body tissue. On-body performance is analysed on three layered equivalent tissue phantom model. Antenna shows reflection coefficient of -40 dB, efficiency of 58% and directivity of 6.7 dBi when operated in close proximity of body tissue with dielectric reflector. unidirectional radiation pattern and low specific absorption rate makes antenna suitable for on-body communication. Further, diversity performance is measured in terms of envelope correlation coefficient (ECC) and diversity gain (DG). Value of ECC is 0.045 and DG is 9.7 dB at 2.45 GHz. Antenna robustness is examined by bending the structure along x-axis. Performance of the proposed structure makes it a suitable candidate for on-body communication.