Design and Analysis of a Conformal MIMO Ingestible Bolus Sensor Antenna for Wireless Capsule Endoscopy for Animal Husbandry

This work portrays the design and analysis of an ingestible capsule multiple-input-multiple-output (MIMO) antenna for wireless capsule endoscopy (WCE) for animal husbandry. The proposed antenna element has a footprint of <inline-formula> <tex-math notation="LaTeX">$0.18\lambda _{{0}}\,\,\times \,\,0.107\lambda _{{0}}\,\,\times \,\,0.002\lambda _{{0}}$ </tex-math></inline-formula>, which is transformed into a four-port MIMO antenna and bent into a cylindrical profile of 8.92 mm radius with dimensions of <inline-formula> <tex-math notation="LaTeX">$0.184\lambda _{{0}}\,\,\times \,\,0.136\lambda _{{0}}\,\,\times \,\,0.002\lambda _{{0}}$ </tex-math></inline-formula>. The designed MIMO configuration consists of asymmetric extended fork-shaped radiators with U-slotted strips and meandered connected ground planes. The developed MIMO set is housed inside a polylactide (PLA) capsule that mimics a real-time pill camera. The capsule antenna operates at the Industrial, Scientific, and Medical (ISM) (2.45 GHz) and ultra-wideband (UWB) (3.1–10.6 GHz) frequencies. The link budget analysis and diversity metrics of the MIMO antenna are evaluated by embedding it inside the capsule. The MIMO bolus sensor antenna prototype is implanted in the skin mimicking gel and its impedance/radiation characteristics are studied. The estimated specific absorption rate (SAR) is found to be within the standard acceptable limits. Furthermore, machine learning approach is introduced for classification of animal type and early detection of animal medical illness, making it suitable for use in animal husbandry-capsule endoscopy, biomedical and biotelemetry applications due to its conformal and biocompatible nature.