Characterization of a Miniature Broadband Antenna for Implantable Neuromodulation Devices

Fully implantable wireless telemetry systems improve the performance and reliability of neural interfaces by eliminating infection-prone percutaneous cables. Meanwhile, wireless links with high data rates are required to meet the growing demand for high-density neural interfaces. This work presents the design and characterization of a miniature broadband antenna used in an ultra-high data rate wireless transmitter for an implantable neural recording and neuromodulation system-on-chip. The implantable antenna, with a total area of 14 mm2 on the printed circuit, is characterized in vitro by being subcutaneously implanted in a chicken phantom. The antenna has a bandwidth of 11.3% in terms of the VSWR, and its radiation pattern is measured at the operating frequency of 4.6 GHz. In the measurement of a wireless system at a distance of 20cm, the 3-dB bandwidth of the wireless link efficiency reaches 830 MHz between the implantable antenna and an external horn antenna.