DESIGN AND ANALYSIS OF ANTENNAS FOR BIOMEDICAL APPLICATIONS

Abstract

Antennas are widely used in biomedical applications such as biotelemetry, capsule endoscopy, and microwave ablation therapy. Design of these antennas faces many challenges such as safety concerns, size limitation, varying operating environment, and demands for a wide band or multiple bands. In this thesis, various types of capsule antennas have been proposed, namely, an ultra-wideband capsule antenna for high-data-rate communications, dual-/tri-band capsule antennas for multi-function capsule systems, and a pattern reconfigurable capsule antenna for stable communications. In addition, the circularly polarized (CP) and dual-polarized (DP) capsule antennas are compared for ingestible capsules. It is found that, in contrast to the usual belief, the CP antennas actually do not provide a more robust communication with the external equipment than do the DP even linearly polarized antennas. A simple and effective communication scheme is then proposed for the capsule systems.