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Abstract: Antenna is very crucial to radiotelemetry capsules which can measure the physiological parameters of the gastrointestinal (GI) tract. The objective of this paper is to design a novel spiral slots microstrip patch antenna for the radiotelemetry capsules communicating with external recorder at 915 MHz located in ISM (Industry, Science, and Medical) bands. The microstrip patch antenna is designed and evaluated using the finite-difference time-domain (FDTD) method. Return loss characteristics and the effect of the human body on resonant frequency are analyzed, and the performances of radiation patterns at different positions of the human alimentary tract are also estimated. Finally, specific absorption rate (SAR) computations are performed, and the peak 1-g and 10-g SAR values are calculated. According to the peak SAR values, the maximum delivered power for the designed antenna was found so that the SAR values of the antenna satisfy the ANSI (American National Standards Institute) limitations.

[1] Berenger, J.P., 1996. Perfectly matched layer for FDTD solution of wave structure interaction problems. IEEE Trans. on Antennas and Propagation, 44:110-117.

[2] Chirwa, L.C., Hammond, P.A., Roy, S., Cumming, R.S., 2003. Electromagnetic radiation from ingested sources in the human intestine between 150 MHz and 1.2 GHz. IEEE Trans. on Biomed. Eng., 50(4):484-492.

[3] Gabriel, C., Gabriel, S., Corthout, E., 1996. The dielectric properties of biological tissues: I. literature survey. Phys. Med. Biol., 41:2231-2249.

[4] Gandhi, O.P., Lazz, G., Furse, C.M., 1996. Electromagnetic absorption in the human head and neck for mobile telephones at 835 and 1900 MHz. IEEE Trans. on Microwave Theory Techniques, 44:1884-1897.

[5] Gupta, K.C., 1988. Microstrip Antenna Design. Artech House, Norwood, p.41-65.

[6] Iddan, G., Meron, G., Glukhovsky, A., Swain, P., 2000. Wireless capsule endoscopy. Nature, 405:417-418.

[7] IEEE Standard C95.1-1999, 1999. Safety Levels with respect to Human Exposure to Radio Frequency Electromagnetic Fields 3 kHz to 300 GHz.

[8] Johannessen, E.A., Wang, L., Cathy, W., David, R.S.C., Jon, M.C., 2006. Biocompatibility of a lab-on-a-pill sensor in artificial gastrointestinal environments. IEEE Trans. on Biomed. Eng., 53(11):2333-2340.

[9] Kim, J., Rahmat-Samii, Y., 2004. Implanted antennas inside a human body: simulations, designs, and characterizations. IEEE Trans. on Microwave Theory Techniques, 52:1934-1943.

[10] Kim, J.M., Oh, D., Yoon, J., Cho, S., Kim, N., Cho, J., Kwon, Y., Cheon, C., Kim, Y.K., 2005. In vitro and in vivo measurement for biological applications using micromachined probe. IEEE Trans. on Microwave Theory Techniques, 53:3415-3421.

[11] Lazzi, G., Gandhi, O.P., Sullivan, D.M., 2000. Use of PML absorbing layers for the truncation of the head model in cellular telephone simulations. IEEE Trans. on Microwave Theory Techniques, 48:2033-2039.

[12] Lin, J.C., 1975. Microwave properties of fresh mammalian brai tissues at body temperature. IEEE Trans. on Biomed. Eng., 22:74-79.

[13] Liu, Z.D., Hall, P.S., Wake, D., 1997. Dual-frequency planar inverted-F antenna. IEEE Trans. on Antennas and Propagation, 45:1451-1457.

[14] Pandolfino, J.E., Richter, J.E., Ours, T., Guardino, J.M., Chapman, J., Kahrilas, P.J., 2003. Ambulatory esophageal pH monitoring using a wireless system. Am. J. Gastroenterol., 98(4):740-749.

[15] Scanlon, W.G., Evans, N.E., 2000. Radiowave propagation from a tissue implanted source at 418 MHz and 916.5 MHz. IEEE Trans. on Biomed. Eng., 47:527-534.

[16] Soontornpipit, P., Furse, C.M., You, C.C., 2004. Design of implantable microstrip antenna for communication with medical implants. IEEE Trans. on Microwave Theory Techniques, 52:1944-1951.

[17] Wang, L., Johannessen, E.A., Hammond, P., Cui, L., Cooper, J.M., Reid, S.W.J., Cumming, D.R.S., 2005. A programmable microsystem using system-on-chip for real-time biotelemetry. IEEE Trans. on Biomed. Eng., 52(7):1251-1260.

[18] Yee, K.S., 1966. Numerical solution of initial boundary value problems involving Maxwell’s equations in isotropic media. IEEE Trans. on Antennas and Propagation, 14(3):302-307.