Integrated Design of Wideband Omnidirectional Antenna and Electronic Components for Wireless Capsule Endoscopy Systems

Abstract

This paper presents a wideband antenna with omnidirectional radiation pattern for wireless capsule endoscopy (WCE) systems. The proposed antenna radiates as slot structure formed between a central copper cylinder and a copper strip attached to the interior surface of biocompatible polyimide shell. Main features of the antenna include: 1) an integrated design of the antenna and electronic components in the capsule is employed. And by utilizing the entire inner space of the capsule, the radiating aperture of antenna is increased to the maximum; 2) the copper cylinder can be used to house electronic components, therefore the potential electromagnetic interferences brought by battery and electronic circuits are reduced to the minimum; 3) the antenna in tissue has a wide bandwidth from 0.721 to 1.705 GHz, covering both 0.902-0.928-GHz industrial, scientific, and medical band and 1.395-1.4-GHz wireless medical telemetry service band; and 4) the antenna inside human tissues has stable omnidirectional radiation patterns across all operating frequencies. This is an indispensable characteristic due to unpredictable orientation of the capsule in gastrointestinal tract. The integrated design concept, wideband impedance matching, and stable omnidirectional radiation patterns make the proposed antenna a promising candidate for future WCE system.

Keywords

• Wireless capsule antenna
• integrated design
• wideband
• ISM band
• WMTS band
• omnidirectional radiation pattern