臺灣博碩士論文加值系統

行動通訊手機天線與人體頭部的電磁耦合作用，對研究人體吸收電磁輻射能量安全標準是重要的議題。本論文使用有限時域差分法(finite difference time domain; FDTD) 電磁數值計算方法來模擬探討手機天線和人體頭部間的電磁耦合及吸收能量特性。首先，使用三維多層超橢圓體之人體頭部組織模型來描述不同厚度之脂肪組織層，探討頭部靠近900及1800 MHz 偶極天線時之電磁能量特定吸收率(SAR)分布。使用三維多層超橢圓體之人體頭部模型靠近偶極天線，並以改變超橢圓體數學方程之技巧來描述不同厚度之脂肪組織層，探討不同厚度脂肪層情況下頭部組織之SAR分布，並與使用二種核磁共振造影(MRI)之實際人頭模型之數值計算結果比較分析。然後，論文中設計一900/1800 MHz 雙頻矩形金屬線狀手機天線，並且以FDTD 計算當被手握持貼近在人體頭部時之天線輻射特性變化及頭部SAR 分布。 最後，論文中設計一運用於無線區域網路之2.4-GHz極化分集選擇電路平面式偶極天線，以FDTD 模擬設計包括極化分集選擇電路pin-diode 及R/L/C 元件之整體天線結構 ，其整體輻射特性可有效增進接收極化分集之性能。

The electromagnetic (EM) interaction of handset antennas with the human head becomes an important issue due to the increasing concern about the EM exposure safety. The EM absorption characteristics for two scenarios are studied in this thesis: (1) a multilayered head model proximate to a dipole antenna, and (2) two MRI-based head models proximate to a proposed dual-band rectangular loop antenna mounted on a handset at 900/1800 MHz. The three-dimensional finite-difference time-domain (3-D FDTD) method is employed to compute this antenna-head coupling problem. The multilayered superquadric ellipsoid head is composed of 9 different tissues of skin, cartilage, fat, muscle, bone, blood, nerve, brain, and eye-lens. The distributions of different specific absorption (SAR) characteristics and the fat layer effects of the head model with different fat-layer thickness are investigated and presented. Furthermore, two realistic MRI-based head models are also used in this study to perform a comparison with the results from the proposed head model. Then, a dual-band rectangular loop antenna on a mobile handset is proposed to study the EM interaction with the above two MRI-based tissue-classified head models. In this study, a hand model with 3 tissues of skin, muscle and bone is included to simulate a hand holding the handset. The characteristics on EM energy absorption of these head models are discussed. Several interesting phenomena are observed and explained. This study provides some important guidelines for the investigation of the exposure assessment and antenna design of the wireless handset. Finally, the 3-D FDTD with Berenger PML-ABC computational method is employed to design and analyze the entire structure of a planar 2.4-GHz polarization-diversity printed dipole antenna for WLAN communication applications.

Chapter 1 Introduction .................................................................................................1
1.1 General introduction .....................................................................................1
1.2 Background information ....................................................................................3
1.3 Motivation for research.......................................................................................4
1.4 Outline of thesis .................................................................................................5
Chapter 2 EM Interaction of A Multilayered Superquadric-Ellipsoidal and
MRI-Based Head Models with A Proximate Dipole Antenna ..............................7
2.1 Introduction........................................................................................................7
2.2 Computational models .......................................................................................9
2.2.1 Human head model .........................................................................................9
2.2.2 Antenna model ..............................................................................................11
2.3 Numerical results and discussions ...................................................................12
2.3.1 Multi-layered superquadric ellipsoidal head model......................................15
2.3.2 MRI-based head models................................................................................21
2.3.3 Antenna patterns affected by human heads ..................................................25
2.4 Summary and conclusion ................................................................................28
Chapter 3 A 900/1800 MHz Dual-Band Gap Loop Antenna on a Handset with a
Proximate Head and Hand..................................................................................31
3.1 Introduction......................................................................................................31
3.2 Computational analysis ...................................................................................33
3.2.1 Antenna structure design..............................................................................33
3.2.2 Head and hand models ................................................................................37
3.3 Numerical simulation and experimental measurement...................................41
3.3.1 Dual-band antenna ......................................................................................41
3.3.2 Effects of cellphone with dual-band gap loop antenna on Brooks and NIT
heads with hand model.........................................................................................49
3.4 Discussion and conclusion.............................................................................57
Chapter 4 FDTD Design Analysis of Printed Planar Dipole Antennas for
WLAN and Wireless Communication Applications ..........................................59
4.1 Introduction....................................................................................................59
4.2 Printed dipole antenna with integrated via-hole balun .................................61
4.3 Polarization-diversity printed dipole antenna with polarization- switching
Circuit .................................................................................................................69
4.4 Conclusion .............................................................................................79
Chapter 5 Conclusion .......................................................................................81
References...........................................................................................................83

[1] D. E. Livesay and K.-M. Chen,“Electromagnetic fields induced inside arbitrarily shaped biological bodies,” IEEE Transactions on Microwave Theory and Techniques, vol. 22, no. 12, pp. 1273-1280, Dec. 1974.
[2] K.-M. Chen and B. S. Guru, “Internal EM field and absorbed power density in human torsos induced by 1-500-MHz EM waves,” IEEE Transactions on Microwave Theory and Techniques, vol. 25, no. 9, pp. 746-756, Sept. 1977.
[3] K. Karimullah, K.-M. Chen, and D. P. Nyquist, “Electromagnetic coupling between a thin-wire antenna and a neighboring biological body: Theory and experiment,” IEEE Transactions on Microwave Theory and Techniques, vol.28, no. 11, pp. 1218-1225, Nov. 1980.
[4] K. S. Yee, “Numerical solution of initial boundary value problems involving Maxwell’s equations in isotropic media,” IEEE Transactions on Antennas Propagation, vol. 14, pp. 302-307, May 1966.
[5] A. Taflove and M. E. Brodwin, “Numerical solution of steady-state electromagnetic scattering problems using the time-dependent Maxwell’s equations,” IEEE Transactions on Microwave Theory and Techniques, vol. 23, no. 8, pp. 623-630, Aug. 1975.
[6] A. Taflove, “Application of the finite-difference time-domain method to sinusoidal steady-state electromagnetic-penetration problems,” IEEE Transactions on Electromagnetic Compatibility, vol. 22, no. 3, pp. 191-202, Aug. 1980.
[7] P. J. Dimbylow, “FDTD calculations of the SAR for a dipole closely coupled to the head at 900 MHz and 1.9 GHz,” Phys. Med. Biol., vol. 38, pp. 361-368,1993.
[8] M. A. Jensen and Y. Rahmat-Samii,“Performance analysis of antennas for hand-held transceivers using FDTD,” IEEE Transactions on Antennas Propagation, vol. 42, pp. 1106-1113, 1994.
[9] H.-Y. Chen and H.-H. Wang, “Current and SAR induced in a human head model by the electromagnetic fields irradiated from a cellular phone,” IEEE Transactions on Microwave Theory and Techniques, vol. 42, no. 12, pp. 2249-2254, Dec. 1994.
[10] J. E. Storer, “Impedance of thin-wire loop antennas,” Amer. Inst. Elec. Eng. Trans., vol. 75, pt. 1, pp. 606-619, Nov. 1956.
[11] T. T. Wu, “Theory of the thin circular loop antenna,” J. Math. Phys., vol. 3, pp.1301-1304, Nov.-Dec. 1962.
[12] R. F. Harrington and J. Mautz,“Electromagnetic behavior of circular wire loops with arbitrary excitation and loading,”Proc. IEE, vol. 115, pp. 68-77, Jan. 1968.
[13] C. M. Weil, “Absorption characteristics of multilayered sphere models exposed to UHF/microwave radiation,” IEEE Trans. Biomed. Eng., Vol.BME-22, 468-476, Nov. 1975.
[14] H. N. Kriticos and H. P. Schwan, “Formation of hot spots in multilayered spheres,” IEEE Trans. Biomed. Eng., Vol. BME-23, 168-172, Mar. 1976.
[15] M. F. Iskander, P. W. Barber, C. H. Durney, and H. Massoudi, “Irradiation of prolate spheroidal models of humans in the near field of a short electric dipole, ”IEEE Transactions on Microwave Theory Techniques, Vol. MTT-28, 801-807, July 1980.
[16] N. K. Uzunoglu and E. A. Angelikas, “Field distributions in a three-layer prolate spheroidal human body model for a loop antenna irradiation,” IEEE Transactions on Antennas Propagation, Vol. AP-35, 1180-1185, Oct. 1987.
[17] L. Li, P. Kooi, M. S. Leong, and T. S. Yeo, “Electromagnetic dyadic Green’s function in spherically multilayered media,” IEEE Transactions on Microwave Theory and Techniques, Vol. 42, 2302-2309, Dec.1994.
[18] N. C. Skaropoulos, M. P. Ioannidou, and D. P. Chrissoulidis, “Induced EM field in a layered eccentric spheres model of the head: plane-wave and localized source exposure,” IEEE Transactions on Microwave Theory Techniques, Vol. 44, 1963-1973, Oct. 1996.
[19] G. Cerri, R. De Leo, and G. Rosellini, “Evaluation of electromagnetic power deposition in a spherical multilayer head in the near field of a linear antenna,”Wireless Networks, Vol. 3, 499-510, 1997.
[20] S. Nishizawa and O. Hashimoto, “Effectiveness analysis of lossy dielectric shields for a three-layered human model,” IEEE Transactions on Microwave Theory and Techniques, Vol. 47, No. 3, 277-283, March 1999.
[21] K. S. Nikita, G. S. Stamatakos, N. K. Uzunoglu, and A. Karafotias, “Analysis of the interaction between a layered spherical human head model and a finite-length dipole,” IEEE Transactions on Microwave Theory Techniques, Vol. 48, 2003-2013, Nov. 2000.
[22] S. Koulouridis and K. S. Nikita, “Study of the coupling between human head and cellular phone helical antennas,” IEEE Transactions on Electromagnetic Compatibility, Vol. 46, No.1, 62-70, Feb. 2004.
[23] K. W. Kim and Y. Rahmat-Samii, “EM interactions between handheld antennas and human: anatomical head vs. multi-layered spherical head,” IEEE-APS Conference on Antennas and Propagation for Wireless Communications, 69-72, Waltham, Mass., Nov. 1998.
[24] J. James and K. Fujimoto, Mobile Antenna Systems Handbook, 2nd Edition, Ch.7 (Antenna and Humans in Personal Communications), Artech House, 2002.
[25] A. Drossos, V. Santomaa, and N. Kuster, “The dependence of electromagnetic energy absorption upon human head tissue composition in the frequency range of 300-3000 MHz,” IEEE Transactions on Microwave Theory and Techniques, Vol.48, No.11, 1988-1995, 2000.
[26] H. P. Schwan and K. Li, “Hazards due to total body irradiation by radar,”Proc. IRE, Vol.44, 1572-1580, 1956.
[27] C. Polk and E. Postow, Handbook of Biological Effects of Electromagnetic Fields, 338-345,CRC Press, 1996.
[28] H.-R. Chuang, “Numerical computation of fat layer effects on microwave near-field radiation to the abdomen of a full-scale human body model,” IEEE Transactions on Microwave Theory and Techniques, Vol. 45, No.1, 118-125, January 1997.
[29] N. Stevens and L. Martens, “Comparison of averaging procedures for SAR distributions at 900 and 1800 MHz,” IEEE Transactions on Microwave Theory and Techniques, Vol. 48, No.11, 2180-2184, Nov. 2000.
[30] M. Okoniewki and M. A. Stuchly, “A study of the handset antenna and human body interaction, ”IEEE Transactions on Microwave Theory and Techniques, Vol. 44, No. 10, 1855-1864, Oct. 1996.
[31] V. Hombach, K. Meier, M. Burkhardt, E. Kuhn, and N. Kuster, “The dependence of EM energy absorption upon human head modeling at 900 MHz,” IEEE Transactions on Microwave Theory and Techniques, Vol. 44, No.10, 1865-1873, Oct. 1996.
[32] K. Meier, V. Hombach, R. Kastle, R. Y.-S. Tay, and N. Kuster, “The dependence of electromagnetic energy absorption upon human-head modeling at 1800 MHz,” IEEE Transactions on Microwave Theory and Techniques, Vol.45, No.11, 2058-2062, Nov. 1997.
[33] G. Lazzi, O. P. Gandhi, and D. M. Sullivan, “Use of PML absorbing layers for the truncation of the head model in cellular telephone simulations,” IEEE Transactions on Microwave Theory and Techniques, Vol. 48, No. 11, 2033-2039, Nov. 2000.
[34] A. Schiavoni, P. Bertotto, G. Richiardi, and P. Bielli, “SAR generated by commercial cellular phones-phone modeling, head modeling, and measurements,” IEEE Transactions on Microwave Theory and Techniques, Vol. 48, No. 11, 2064-2071, Nov. 2000.
[35] P. Bernardi, M. Cavagnaro, S. Pisa, and E. Piuzzi, “Power absorption and temperature elevations induced in the human head by a dual-band monopole-helix antenna phone,” IEEE Transactions on Microwave Theory and Techniques, Vol. 49, No.12, 2539-2546, Dec. 2001.
[36] A. Hirata, M. Morita, and T. Shiozawa, “Temperature increase in the human head due to a dipole antenna at microwave frequencies,” IEEE Transactions on Electromagnetic Compatibility, Vol. 45, No.1, 109-116, Feb. 2003.
[37] O. Kivekas, J. Ollikainen, T. Lehtiniemi, and P. Vainikainen, “Bandwidth,SAR, and efficiency of internal mobile phone antennas,” IEEE Transactions on Electromagnetic Compatibility, Vol. 45, No. 1, 71-86, Feb. 2004.
[38] W. Guy, "Dosimetry of radiofrequency of electromagnetic fields: examples of results using numerical methods," Health Physics Society Summer School Course on Non-Ionizing Radiation, San Antonic, Texas, 1997. [Online]: http://www.brooks.af.mil/AFRL/HED/hedr/hedr.html
[39] J. Wang and O. Fujiwara, "FDTD Computation of temperature rise in the human head for portable telephones," IEEE Transactions on Microwave Theory and Techniques, vol. 47, No. 8, pp. 1528-1534, August 1999.
[40] O. Gandhi and G. Lazzi, “The role of a lossy ear in altering the SAR distributions due to wireless telephones,” Proc.XXVI General Assembly of URSI, 13-21, Vol. 634, Toronto, Canada, Aug. 1999.
[41] M. Burkhardt and N. Kuster, “Appropriate modeling of the ear for compliance testing of handheld MTE with SAR safety limits at 900/1800 MHz,” IEEE Transactions on Microwave Theory and Techniques, Vol. 48, No. 11, 1927-1934, Nov. 2000.
[42] M. Kanda, Q. Balzano, P. Russo, A. Faraone,and G. Bit-Babik, “Effects of ear-connection modeling on the electromagnetic-energy absorption in a human-head phantom exposed to a dipole antenna field at 835 MHz,” IEEE Transactions on Electromagnetic Compatibility, Vol.44, No.1, pp. 4-10, Feb. 2002.
[43] C. Gabriel, “Compilation of the dielectric properties of body tissues at RF and microwave frequencies,” Brooks Air Force Base, Brooks AFB, TX, Tech. Rep. AL/OE-TR-1996-0037, 1996. [Online]: http://www.fcc.gov/cgi-bin/dielec.sh.
[44] R. Holland, J. Fogler, and G. W. Donohoe, “Human body modeling for evalution of electromagnetic hazards,” IEEE 46th Vehicular Technology Conference, Vol. 1, pp. 654-657, 1996.
[45] J. Wang and O. Fujiwara, “Comparison and evaluation of electromagnetic absorption characteristics in realistic human head models of adult and children for 900-MHz mobile telephones,” IEEE Transactions on Microwave Theory and Techniques, vol. 51, No. 3, pp. 966- 971, March 2003.
[46] K. R. Umashankar, A. Taflove, and B. Beker, “Calculation and experimental validation of induced currents on coupled wires in an arbitrary shaped cavity,”IEEE Transaction on Antennas and Propagation, Vol. 35, 1248-1257, Nov.1987.
[47] IEEE Standard for Safety with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz, IEEE Standard C95.1-1999, 1999.
[48] IEEE Standard for Safety Levels With Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz, Amendment 2: Specific Absorption Rate (SAR) Limits for the Pinna, IEEE Standard C95.1b-2004, Dec. 2004.
[49] M. F. Iskande, Z. Yun, and R. Quintero-Illera, “Polarization and human body effects on the microwave absorption in a human head exposed to radiation from handheld devices,” IEEE Transactions on Microwave Theory and Techniques, vol. 48, No. 11, pp. 1979-1987, Nov. 2000.
[50] A. Hirata and T. Shiozawa, “Correlation of maximum temperature increase and peak SAR in the human head due to handset antennas,” IEEE Transactions on Microwave Theory and Techniques, vol. 51, No.7, pp. 1834-1841, July 2003.
[51] S. Watanable, M. Taki, T. Nojima and O. Fujiwara, “Characteristics of the SAR distributions in a head exposed to electromagnetic fields radiated by a hand-held portable,” IEEE Transactions on Microwave Theory and Techniques, vol. 44, No. 10, pp. 1874-1883, Oct. 1996.
[52] G. Lazzi and O. P. Gandhi, “On modeling and personal dosimetry of cellular telephone helical antennas with the FDTD code,” IEEE Transactions on Antennas and Propagation, vol. 46, No. 4, pp. 525-530, April 1998.
[53] J. T. Rowley and R. B. Waterhouse, “Performance of shorted microstrip patch antennas for mobile communications handsets at 1800 MHz,” IEEE Transactions on Antennas and Propagation, vol. 47, No. 5, pp. 815–822, May 1999.
[54] A. Hadjem, D. Lautru, C. Dale, M. F. Wong, V. F. Hanna, and J. Wiart, “Study of specific absorption rate (SAR) induced in two child head models and in adult heads using mobile phones,” IEEE Transactions on Microwave Theory and Techniques, vol. 53, No. 1, pp. 4-11, Jan. 2005.
[55] R. L. Li, E. M. Tentzeris, J. Laskar, V. F. Fusco, and R. Cahill, Broadband loop antenna for DCS-1800/IMT-2000 Mobile Phone Handsets,” IEEE Microwave and Wireless Components Letters, vol. 12, No. 8, pp. 305-307, Aug. 2002.
[56] P. Haapala, P. Vainikainen and P. Eratuuli, “Dual frequency helical antennas for handsets,” IEEE 46th Vehicular Technology Conference, Vol. 1, pp. 336-338,1996.
[57] J. Ollikainen, O. Kivekäs, A. Toropainen, and P. Vainikainen, “Internal dual-band patch antenna for mobile phones,” AP2000 Millennium Conference on Antennas & Propagation. Davos, Switzerland, 9-14 April 2000.
[58] M. Ali, G. J. Hayes, H. S. Hwang and R. A. Sadler, “Design of a multiband internal antenna for third generation mobile phone handsets,” IEEE Transaction on Antennas and Propagation, vol. 51, pp. 1452-1461, July2003.
[59] K. S. Kunz and R. J. Luebbers, Finite difference time domain method for electromagnetics, CRC Press, 1993.
[60] P. A. Tirkas and C. A. Balanis, “Modeling of thin dielectric structures using the finite-difference time-domain technique,” IEEE Transaction on Antennas and Propagation, vol. 39, pp. 1338-1344, 1991.
[61] J. J. Boonzaaier and C. W. I. Pistonius, “Finite-difference time-domain field approximates for thin wires with a lossy coating,” IEE Proc.-Microw. Antennas Propag., vol. 141, no. 2, April 1994.
[62] K. Fujimoto and J. R. James, Mobile Antenna Systems Handbook, Norwood, M.A., Artech House, 1994.
[63] R. P. Kronberger, H. K. Lindenmeiner, L. M. Reiter, and J. F. Hopf, “Array antenna principle applied to modern antennas for mobile communication,” IEEE AP-S International Symposium, pp.2224-2227, 1998.
[64] J. Preiss et al., "Polarization diverse antenna for portable communication devices", US patent #6,031,503, 2000.
[65] S. N. Tsai et al., "Antenna module for portable computer", US patent #6,297,779, 2001.
[66] D. Edward and D. Rees, “A broadband printed dipole with integrated balun”,Microwave Journal, pp. 339-344, May 1987.
[67] N. Michishita, H. Arai, M. Nakano, T. Satoh, and T. Matsuoka, “FDTD analysis for printed dipole antenna with balun’, Asia-Pacific Microwave Conference, pp.739-742, 2000.
[68] G. S. Hilton, C.J. Railton, G.J. Ball, A.L. Hume, and M. Dean,“Finite-difference time-domain analysis of a printed dipole antenna”, Ninth International Conference on Antennas and Propagation, 1995, vol.1, pp.72-75, 1995.
[69] P. M. Melinda, A. Taflove, and John Baron, “FD-TD modeling of digital signal propagation in 3-D circuits with passive and active loads”, IEEE Transactions on Microwave Theory and Techniques, vol. 42, No. 8, pp. 1514-1523, Aug. 1994.
[70] J. P. Berenger, “A perfectly matched layer for the absorption of electromagnetic waves”, J. Computational Physics, vol. 114, pp. 185-200, 1994.
[71] X. Zhang and K. K. Mei, “Time-domain finite difference approach to the calculation of the frequency-dependent characteristics of microstrip discontinuities”, IEEE Trans. on Microwave Theory and Techniques, vol. 36, No. 12, pp. 1775-1787, Dec. 1988.
[72] J. Fang and J. Ren, “A locally conformed finite-difference time-domain algorithm of modeling arbitrary shape planar metal strips”, IEEE Transactions on Microwave Theory and Techniques, vol. 41, No. 5, pp. 830-838, May. 1997.
[73] D. Koh, H.-B. Lee, and T. Itoh, “A Hybrid Full-Wave Analysis of Via-Hole Grounds Using Finite-difference and Finite-Element Time-Domain Methods”, IEEE Transactions on Microwave Theory and Techniques, vol. 45, No. 12, pp. 2217-2223, Dec. 1997.
[74] A. Taflove, Advances in computational electrodynamics the finite-difference time domain method, Artech House, 1996.
[75] D. M. Pozar, Microwave Engineering, pp. 576, John Wiley & Sons, 1998.