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

This paper presents a wideband antenna with

omnidirectional radiation pattern for wireless capsule endoscopy

(WCE) systems. The proposed antenna radiates as a 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 (EMI)

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 (ISM) band and 1.395-1.4 GHz Wireless

Medical Telemetry Service (WMTS) band. This is achieved by

optimizing the stepped width of copper strip; 4). The antenna

inside human tissues has stable omnidirectional radiation patterns

across all operating frequencies. This is an indispensable

characteristic due to the unpredictable orientation of capsule in

the gastrointestinal (GI) tract. Stable patterns are achieved by

having strong electric fields concentrated within the top substrate

pointing at the same direction. The integrated design concept,

wideband impedance matching and stable omnidirectional

radiation patterns make the proposed antenna a promising

candidate for future WCE system.