Miniaturised Implantable Antenna for Wireless Capsule Endoscopy

Abstract

This thesis investigates the development of miniaturised implantable antennas for wireless capsule endoscopy (WCE) applications. The study addresses critical challenges, including the integration of an antenna within the
limited space of a small capsule, frequency detuning caused by the heterogeneous human body, and the significant signal propagation losses. Several implantable antenna designs were explored, including in-band full-duplex (IBFD) and dual-band configurations, with prototypes fabricated and experimentally validated. Simulation and measurement results demonstrate strong alignment. The study emphasises the necessity of an omnidirectional radiation pattern to ensure reliable communication regardless of the capsule’s
rotation within the GI tract. To ensure patient safety, specific absorption rate (SAR) levels were thoroughly evaluated. The study incorporates advanced miniaturisation techniques, and precise optimisation to achieve high performance in a compact form factor. The proposed dual port implantable antennas design demonstrates high isolation, good impedance matching, and independently controllable frequency bands. These features enhance spectral efficiency and support simultaneous transmission and reception for real-time bidirectional communication. This study contributes to the first ever reported IBFD antenna that offer reliable, efficient, and safe performance in
the dynamic environment of the human body. The findings not only enhance the capability of WCE systems but also pave the way for future developments in non-invasive diagnostic technologies.