A multi-band cylindrical conformal endoscopy antenna with low specific absorption rate (SAR) is designed for endoscope applications, which covers the Industrial, Scientific and Medical bands (ISM 902-928 MHz, 2.4-2.4835 GHz), Medical Device Radio Communications Service band (MedRadio 401-406 MHz) and Wireless Medical Telemetry Service (WMTS 608-614 MHz). The proposed antenna radiates as a symmetrical meanderline structure with a center loaded parasitic opened-loop element, which is bent into the cylindrical conformal shape and wrapped onto the inner wall of the capsule shell. The parasitic opened-loop element excites low frequency resonance at 403 MHz and reduces the SAR values of the antenna. The measured relative bandwidth (|S11| < -10 dB) of the antenna implements 133% ultra-wideband, ranging from 0.35 GHz to 1.76 GHz, and 39% wideband, ranging from 2.01 GHz to 3 GHz. The peak gains and the peak 1 g SAR values at 403 MHz, 611 MHz, 915 MHz, 2.4 GHz are -26.6 dBi, -18.9 dBi, -11.8 dBi, -11.3 dBi, and 83, 82, 94, 153 W/kg, respectively. The results indicate that the proposed antenna complies well with the human safety standards.
2. Xing, B., Y. Zhang, H. Zou, and Z. Liu, "A conformal quasi-isotropic dielectric resonator antenna for wireless capsule endoscope application," Progress In Electromagnetics Research M, Vol. 99, 211-221, 2021.
3. Patil, K. S. and E. Rufus, "A review on antennas for biomedical implants used for IoT based health care," Sensor Review, Vol. 40, 273-280, 2019.
4. Peng, Y., K. Saito, and K. Ito, "Antenna design for impulse-radio-based wireless capsule endoscope communication systems," IEEE Transactions on Antennas and Propagation, Vol. 66, 5031-5042, 2018.
5. Duan, Z., L.-J. Xu, S. Gao, and G. Wen, "Integrated design of wideband omnidirectional antenna and electronic components for wireless capsule endoscopy systems," IEEE Access, Vol. 6, 29626-29636, 2018.
6. Fiedler, T. M., M. E. Ladd, and A. K. Bitz, "SAR simulations & safety," Neuroimage, Vol. 168, 33-58, 2018.
7. Bao, Z., Y. Guo, and R. Mittra, "Single-layer dual-/tri-band inverted-F antennas for conformal capsule type of applications," IEEE Transactions on Antennas and Propagation, Vol. 65, 7257-7265, 2017.
8. Das, R. and H. Yoo, "A multiband antenna associating wireless monitoring and nonleaky wireless power transfer system for biomedical implants," IEEE Transactions on Microwave Theory and Techniques, Vol. 65, 2485-2495, 2017.
9. Yousaf, M., I. B. Mabrouk, F. Faisal, M. Zada, Z. Bashir, A. Akram, and H. Yoo, "Compacted conformal implantable antenna with multitasking capabilities for ingestible capsule endoscope," IEEE Access, Vol. 8, 157617-157627, 2020.
10. Shang, J. and Y. Yu, "An ultrawideband and conformal antenna for wireless capsule endoscopy," Microwave and Optical Technology Letters, Vol. 62, 860-865, 2020.
11. Wang, J., M. Leach, E. G. Lim, Z. Wang, R. Pei, and Y. Huang, "An implantable and conformal antenna for wireless capsule endoscopy," IEEE Antennas and Wireless Propagation Letters, Vol. 17, 1153-1157, 2018.
12. Shang, J. and Y. Yu, "An ultrawideband capsule antenna for biomedical applications," IEEE Antennas and Wireless Propagation Letters, Vol. 18, 2548-2551, 2019.
13. Basir, A., M. Zada, Y. Cho, and H. Yoo, "A dual-circular-polarized endoscopic antenna with wideband characteristics and wireless biotelemetric link characterization," IEEE Transactions on Antennas and Propagation, Vol. 68, 6953-6963, 2020.
14. Gabriel, S., R. W. Lau, and C. Gabriel, "The dielectric properties of biological tissues: III. Parametric models for the dielectric spectrum of tissues," Physics in Medicine and Biology, Vol. 41, 2271-2293, 1996.
15. Gabriel, S., R. W. Lau, and C. Gabriel, "The dielectric properties of biological tissues: II. Measurements in the frequency range 10 Hz to 20 GHz," Physics in Medicine and Biology, Vol. 41, 2251-2269, 1996.
16. Ga Briel, C. and A. Peyman, "Dielectric properties of biological tissues; Variation with age - Science direct," Conn's Handbook of Models for Human Aging (Second Edition), 939-952, 2018.