Antenna system design for improved wireless capsule endoscope links at 433 MHz

Thumbnail Image
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Degree programme
IEEE Transactions on Antennas and Propagation, Volume 67, issue 4
Wireless capsule endoscopy (WCE) systems are used to capture images of the human digestive tract for medical applications. The antenna is one of the most important components in a WCE system. In this paper, we present novel small antenna solutions for a WCE system operating at the 433 MHz ISM band along with a link budget analysis. The in-body capsule transmitter uses an ultrawideband outer wall conformal loop antenna, whereas the on-body receiver uses a printed monopole antenna with a partial ground plane. A colon-equivalent tissue phantom and CST Gustav voxel human body model were used for the numerical studies of the capsule antenna. The simulation results in the colon-tissue phantom were validated through in vitro measurements using a liquid phantom. According to the phantom simulations, the capsule antenna has -10 dB impedance matching from 309 to 1104 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 same design methodology was applied to on-body antennas followed by in vitro and ex vivo measurements for validation. The on-body antenna exceeds -10 dB impedance matching from 385 to 502 MHz both in simulations and measurements. The path loss for the radio link between an in-body capsule transmitter and an on-body receiver using our antenna solutions, in simulations and measurements, is less than 50 dB for any capsule orientation and location, ensuring sufficient signal level at the receiver, hereby enabling an improved capsule endoscope.
Conformal antenna, in-to-on body propagation, wireless capsule endoscope
Other note
Suzan Miah, M, Khan, A N, Icheln, C, Haneda, K & Takizawa, K I 2019, ' Antenna system design for improved wireless capsule endoscope links at 433 MHz ', IEEE Transactions on Antennas and Propagation, vol. 67, no. 4, 8648490, pp. 2687-2699 .