Performance Analysis of a Conformal Antenna at 433Mhz for Wireless Capsule Endoscopy.

Abstract

Wireless capsule endoscopy is a new technique that permits complete exploration of the small bowel without outside wires. The conformal antenna is an important part of the WCE system. In this thesis work, a compact capsule antenna is proposed operating at the 433-MHz ISM band. The antenna is attached to the outer wall of a small capsule with dimensions of 19.7 mm and 10.2 mm. A colon-equivalent tissue phantom is designed in CST to numerically verify the operation of the capsule antenna. According to the phantom simulations, the capsule antenna has −10 dB impedance matching from 338 to 558MHz and a minimum return loss S11= -35.7db at 339 MHz. The ultrawideband characteristic enables the capsule antenna to tolerate the detuning effects due to electronic modules in the capsule and due to the proximity of various different tissues in gastrointestinal tracts. The maximum gain achieved by this design is 41.39 dBi. While providing ultrawide operational bandwidth and sufficient radiation performance, the small size makes the antenna suitable especially for pediatric patients in addition to adults.