A Compact Self-Duplex Antenna For Wireless Capsule Endoscopic Devices

This paper presents a compact out-of-band duplex antenna for the simultaneous data transmission and reception of capsule endoscopic devices. The proposed antenna involves two slotted semi-circular patches with a 0.4 mm gap. It operates at 1.85 GHz and 2.4 GHz with an isolation level of better than 26 dB. This antenna is designed and optimized in the center of a homogeneous muscle box with an implantation depth of 62 mm. This antenna has compact geometry of 3.67 mm
³
. The miniaturization techniques involve shorting pins and capacitive slots. Good isolation between the transmitting and receiving ports is obtained by keeping a gap of 0.6 mm between them. The main features of this antenna include compact dimensions, high isolation between the ports, and its ability to transmit and receive data simultaneously. Due to these features, the proposed antenna is suitable for implantable devices if two-way communication is required.