Ultra-compact Implantable MIMO Antenna with Radiation Pattern Diversity for Scalp-based Implants

This work presents the development of a new ultra-compact implantable two-element MIMO antenna with radiation diversity for bio-telemetry communication in scalp-based implants. The design consists of two separated mirrored semicircular slotted patches that radiate in dissimilar directions to enable radiation diversity. The proposed antenna occupies a very compact volume of 4.085 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>and is designed to resonate at 2.4 GHz. Two different numerical techniques were used to validate the antenna's performance in a scalp-based environment. Due to symmetry, both antenna's radiating elements achieved a fractional bandwidth of 25.13% and a peak gain of -19.8 dBi at the resonance frequency. The antenna showed an ability to radiate in two dissimilar directions with a radiation coverage angle of ± 60°. Specific absorption rate and link budget analyses were conducted and demonstrated the antenna's ability to perform bio-telemetry communication at high data rates of up to 100 Mbps while satisfying power safety regulations.