An Ultrawideband Conformal Loop Antenna for Ingestible Capsule Endoscope System

In this paper, an ultra wideband loop antenna is presented for capsule endoscope system operating around 433 MHz. The antenna occupies the outer-wall of the capsule and leaves the inner space for the other components of the capsule endoscope module. The proposed capsule antenna has a -10 dB impedance matching bandwidth of 744 MHz (from 336 to 1080 MHz). The ultra wideband characteristic enables the capsule antenna to compensate for detuning effects due to electronics components in the capsule endoscope module, different tissues in the gastrointestinal tract, and implant locations. The antenna has a nearly omnidirectional radiation pattern, which is usually required for such applications. The resonance performance of the fabricated antenna is validated by comparing the measured results with that of simulations when the antenna is placed in a human equivalent liquid phantom.