Compact wideband antenna for wireless capsule endoscopy system

Abstract

This paper proposes an implantable antenna to be used in either planar or conformal arrangements for implanted biomedical devices. The proposed antenna has a wide bandwidth characteristic. When it is in a conformal shape, the antenna can be used for wireless capsule endoscopy applications. In addition, the antenna can be a good candidate for biotelemetry applications while it is planar. A cubic phantom model was adopted in simulations for the initial design and optimization of the conformal antenna structure. The antenna was designed on the outer wall of the capsule to provide more space for other electronics inside. Implanted antennas are subject to detuning effects due to the proximity of various tissues in the gastrointestinal tract, presence of the electronic module in the capsule, different biocompatible coating thicknesses, and different bending conditions. Having a wide bandwidth makes this antenna less sensitive to these detuning effects. Performance of the proposed antenna was experimentally validated in the planar and conformal forms by using a solid muscle-mimicking phantom. Based on measurements, antenna exhibits wide impedance bandwidths, from 170 to 3500 MHz for the conformal antenna, and from 650 to 3600 MHz for the planar antenna inside muscle tissue phantom.