Performance Evaluation of an Ultra-Wideband Transmit Diversity in a Living Animal Experiment

• Published in: IEEE transactions on microwave theory and techniques Vol. 65; no. 7; pp. 2596 - 2606
• Main Authors: Shimizu, Yuto, Anzai, Daisuke, Chavez-Santiago, Raul, Floor, Pal Anders, Balasingham, Ilangko, Wang, Jianqing
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2017; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna measurements; Antennas; Attenuation; Broadband; Communication; Communications systems; Computer simulation; Finite difference method; Implant communication; implantable antenna; Implants; Liquids; living animal experiment; Noise levels; Phantoms; Polarization; Signal to noise ratio; Time domain analysis; transmit diversity; Transmitting antennas; Ultra wideband antennas; ultra-wideband (UWB); Ultrawideband
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2017.2669039

To realize implant communications with a high data rate, ultra-wideband (UWB) transmission has gathered a lot of attention as a promising candidate. However, due to high operation frequency, the UWB communication link suffers from large attenuation. This represents the difficulty to achieve reliable communications. To mitigate such a problem, spatial diversity techniques have been proposed in the literature, where some of them work without any frequency extension. In contrast, the implant side diversity technique has been rarely discussed because of the difficulty in miniaturizing the size of the transmitter antenna. In this paper, we designed a UWB transmitter diversity antenna and evaluated its performance numerically and experimentally. First, we analyzed the antenna performance using a finite-difference time-domain simulation and physical experiment in a liquid phantom. Thereafter, we measured the path loss performance in an implant communication link using a liquid phantom and a living porcine subject. Finally, we evaluated the impact of the implant side polarization diversity system with the developed antenna on the communication performance. Based on the measured isolation between the polarization channels, our measurements show that a signal-to-noise power ratio improvement of 7 dB can be in principle achieved with a predicted outage rate of 0.01 and a range of 15 cm in typical body environments.