Ultra-wide band spiral shaped small antenna for the biomedical telemetry

In this paper, the ultra-wide band spiral shaped small antenna for the implantable micro systems is proposed. Among these implantable systems, the capsule endoscope system operates inside the human body. The human body tissues which have effects on the antenna propagation characteristics are considered. To transmit the diagnostic real-time image data of high resolution at high speed, the system with larger bandwidth is needed. Thus, the bandwidth enhancement of the antenna is needed. To encase the system in the capsule module and to obtain ultra-wide band characteristics, the small sized spiral antenna is designed. The proposed antenna has the bandwidth of 400-510 MHz for VSWR<2 and the fractional bandwidth of 24.1 %. The antenna has the omni-directional radiation pattern and the size of 10.5 mm in diameter and 3 mm in height. Therefore, it is apparent that the proposed antenna provides the ultra-wideband characteristics at the biomedical frequency band and can be utilized to the UWB systems for the biomedical telemetry.