A Compact Dual‐Band Antenna for Brain–Machine Interface and Skin‐Implantable Biotelemetry Applications

This work focuses on designing a compact dual‐band microstrip patch antenna usable for both brain‐ and skin‐implantable biotelemetry applications. The miniaturization is achieved using an E‐shaped meandered resonator over a FR4 substrate with plain ground, resulting a dimension of 13 × 10 × 1.5 mm 3 . Such a shorting pin or slot‐free simple structure is an advantageous feature of the proposed antenna to reduce the fabrication complexity. In the seven‐layer brain tissue model, the antenna operates at the bands of 2.47 and 4.8 GHz with impedance bandwidths of 21.21% and 25.27%, and the gains are −19.7 and −12.3 dBi, respectively. The same antenna also operates in a three‐layer human tissue model at the UWB bands of 3.16 and 6 GHz with impedance bandwidths of 10.7% and 10.53% and gains of −18.7 and −9.12 dBi, respectively. Such wide bandwidths make the antenna less affected by physiological changes among various age groups of people, demonstrating its robust applications in different patients. The gain patterns of the antenna in the E‐ and H‐planes are similar to be omnidirectional and in the off‐body direction as required for the telemetry applications. The system‐level performance of the proposed antenna has also been investigated, including integrating other components of implantable medical devices (IMDs). The evaluated specific absorption rate (SAR) meets the health safety requirements. The measured VSWR is found to be 1.5 and 1.02 in brain tissue, and 1.39 and 1.19 in skin tissue at the respective frequency bands. Furthermore, the link‐budget analysis demonstrates the antenna’s ability to communicate with a receiver antenna positioned 8–39 m away at a high data rate of 1 Mbps to as low as 100 Kbps. Finally, the optimized antenna is fabricated and tested in biological environments for VSWR and reflection coefficients, revealing close agreement between the simulation and the measurement results.