Input Resistance Changes and Related Performances of a Normal-Mode Helical Antenna in a Human Body Application


  • N. Q. Dinh Faculty of Radio-Electronics Engineering Le Quy Don Technical University, Hanoi, Vietnam
  • D. T. Dung Telecommunication University, Khanhhoa, Vietnam
  • Y. Yamada Malaysia-Japan International Institute of Technology Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia
  • N. Michishita Department of Electrical and Electronic Engineering National Defense Academy, Yokosuka, Japan


Human body, NMHA, phantom, RF


Recently, ingestible capsule endoscopy has been developed to ease the dosimetry process in the stomach and tract. In this application, a helical antenna is used because its shape is suitable for a capsule. The electric performance of a coil antenna can be analyzed by the normal-mode helical antenna (NMHA) concept. Previously, the design equations for NMHA have already been developed in free space application. Application of NMHA in the human body is innovative. Antenna design equations and electrical performance should be clarified. Presently, only self-resonant structure equations are clarified. In this paper, fundamental electric performances such as the input resistance, bandwidth and radiation characteristics are clarified through electromagnetic simulations and experiments. As for a human body tissue, the muscle is selected and a muscle phantom is used for measurements. It is made clear, that the input resistance and the bandwidth are increased by the increase of the human body conductivity, while the antenna gains are decreased.


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ACA, “Planning for medical implant communications systems (MICS) & related devices,” Australian Communications Authority, Sydney, NSW, Australia, 2003.

ASGE, “Wireless capsule endoscopy,” American Society Gastrointestinal Endoscopy, Downers Grove, IL, USA, 2013.

T. Karacolak, A. Z. Hood, and E. Topsakal, “Design of a dual-band implantable antenna and development of skin mimicking gels for continuous glucose monitoring,” IEEE Trans. Microw. Theory Techn., vol. 56, no. 4, pp. 1001- 1008, Apr. 2008.

K. Jaehoon and Y. Rahmat-Samii, “Implanted antennas inside a human body: Simulations, designs, and characterizations,” IEEE Trans. Microw. Theory Techn., vol. 52, no. 8, pp. 1934- 943, Aug. 2004.

J. Faerber, et al., “In vivo characterization of a wireless telemetry module for a capsule endoscopy system utilizing a conformal antenna,” IEEE Trans. Biomed. Circuits Syst., vol. 12, no. 1, pp. 95-105, Feb. 2018.

C. Liu, Y. X. Guo, and S. Xiao, “Circularly polarized helical antenna for ISM-band ingestible capsule endoscope systems,” IEEE Trans. Antennas Propag., vol. 62, no. 12, pp. 6027-6039, Dec. 2014.

N. Q. Dinh, N. Michishita, Y. Yamada, and K. Nakatani, “Deterministic equation for selfresonant structures of very small normal-mode helical antennas,” IEICE Trans. Commun., vol. E94-B, no. 5, pp. 1276-1279, May 2011. Online ISSN: 1745-1345, Print ISSN: 0916-8516.

N. T. Tuan, Y. Yamada, N. Q. Dinh, R. H. M. Baharin, K. B. Kamardin, D. T. Dung, and N. Michishita, “Deterministic equation of self resonant structures for normal-mode helical antennas implanted in a human body,” IEEE Antennas and Wireless Propagation Letters, vol. 17, no. 8, pp. 1377-1381, Aug. 2018. Print ISSN: 1536-1225, Online ISSN: 1548-5757, DOI: 10.1109/LAWP.2018.2846600.

N. T. Tuan, M. B. R. Hanan, Y. Yamada, D. T. Dung, N. Q. Dinh, and N. Michishita, “Radiation characteristics of small nomal-mode helical antenna for internal human body sensing,” IIEEJInternational Workshop on Image Electronics and Visual Computing, General session 5A-3, Danang, Vietnam, Mar. 2017.

D. T. Dung, N. Q. Dinh, D. Q. Trinh, and Y. Yamada, “Investigating equations used to design very small normal-mode helical antenna in free space,” International Journal of Antennas and Propagation, vol. 2018, Article ID 7967468, 7 pages, DOI: 10.1155/2018/7967468.

C. Gabriel, “Compilation of the dielectric properties of body tissues at RF and microwave frequencies,” Technical Report AL/OE-TR-1996-0037, Brooks Air Force.

T. Takimoto and T. Onishi, “Characteristics of biological tissues equivalent phantoms applied to UWB communications,” IEICE Trans., pp. 1674- 1681, 2005.




How to Cite

N. Q. Dinh, D. T. Dung, Y. Yamada, & N. Michishita. (2020). Input Resistance Changes and Related Performances of a Normal-Mode Helical Antenna in a Human Body Application. The Applied Computational Electromagnetics Society Journal (ACES), 35(1), 23–30. Retrieved from