Ultra-Compact Camera-Integrated Deep-Implanted Two-Port MIMO Antenna for High-Data-Rate Wireless Capsule Endoscopy

This study proposes a novel high-performance, two-element camera-integrated antenna array for the [401-406] MHz medical device radio communications service (MedRadio) band. The array is designed for integration inside a capsule to establish a stable, high data-rate multiple-input multiple-output (MIMO) wireless communication link for wireless endoscopy. The compact antenna (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pi \times$</tex-math></inline-formula> 1.125 ×1.49 mm<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{3}$</tex-math></inline-formula>) uses stacked meandered resonators, nestled within an annular ring-shaped planar substrate, offering over 7 MHz bandwidth and 41 dB isolation. It achieves a 78 Mbps data rate over 1.6 m in muscle tissue with a specific absorption rate of 2 W/kg at 20 mW power. Measurements show an ECC below 0.001, diversity gain over 9.99 dB, and a channel capacity of 10 bps/Hz at 20 dB SNR. To the best of our knowledge, this is the first dual-camera-integrated MIMO antenna system for the [401-406] MHz MedRadio band tested in an implantable device.