Bodycentric wireless communication Living Tissue Modeling Numerical and
Body-centric wireless communication Living Tissue Modeling: Numerical and Physical Phantoms Zbyněk Raida raida@vut. cz Vytvořeno za podpory projektu OP VVV Moderní a otevřené studium techniky CZ. 02. 2. 69/0. 0/16_015/0002430
Recap § Can you describe fundamental sources of electromagnetic (EM) waves? § Can you explain the first Maxwell equation and the second one in the differential and integral form? § Can you compare a practical way of solving wave equations by finite differences and finite elements? § Can you compare properties of finite differences and finite elements? raida@vut. cz 2
Contents § Interaction of electromagnetic (EM) waves and live tissues [measurements and simulations phantoms] § Numerical phantoms [fidelity of representation versus computational time] § Physical phantoms [agar mixtures, 3 D printing] § Calibration of phantoms raida@vut. cz 3
Body-centric communication § Output signals of living-function sensors aggregated § Information transmitted along body on-body communication § Transmission from the body (digestive tract, implant) in-body communication § Transmission to remote unit off-body communication raida@vut. cz 4
Verification: phantoms § Numerical phantoms Virtual population [online], Zurich (Switzerland): ITIS Foundation, available: http: //www. itis. ethz. ch: raida@vut. cz 5
Voxel phantom A. Christ, W. Kainz, E. G. Hahn, K. Honegger, M. Zefferer, E. Neufeld, W. Rascher, R. Janka, W. Bautz, J. Chen, B. Kiefer, P. Schmitt, H. P. Hollenbach, J. X. Shen, M. Oberle, N. Kuster, The virtual family—Development of anatomical CAD models of two adults and two children for dosimetric simulations, Phys. Med. Biol. , vol. 55, no. 2, pp. 23 -38, Jan. 2010 Volume pixel 1 mm conductivity, permittivity raida@vut. cz 6
Specific absorption rate § Specific Absorption Rate (SAR) denotes EM power absorbed by live tissue weighting 1 kg specific conductivity [S/m] density [kg/m 3] § The SAR limit is 0. 08 W/kg for the whole body and 2 W/kg locally (for frequencies 100 k. Hz to 10 GHz) raida@vut. cz 7
Voxel phantom surface wave dipole in center of chest PÍTRA, K. ; RAIDA, Z. Miniaturized antenna for body-centric communication. European Conference on Antennas and Propagation (Eu. CAP 2013), Gothenburg (Sweden): Eur. AAP, 2013, p. 3119 -3122. raida@vut. cz 8
Layered phantom d [mm] Skin 2 Fat 10 Muscle 28 r [-] [S/m] Skin 38. 063 1. 441 Fat 5. 285 0. 102 Muscle 52. 791 1. 705 2. 4 GHz raida@vut. cz 9
Layered phantom r [-] [S/m] Skin 35. 114 3. 717 Fat 4. 955 0. 293 Muscle 48. 485 4. 962 r [-] [S/m] Skin 7. 975 36. 39 Fat 3. 132 2. 815 Muscle 12. 856 52. 82 5. 8 GHz 60 GHz raida@vut. cz 10
Layered phantom Frequency response of conductivity Frequency response of relative permittivity raida@vut. cz 11
Layered phantom Frequency response of penetration depth raida@vut. cz 12
Surface creeping wave raida@vut. cz 13
Surface creeping wave § Creeping wave horizontal polarization vertical polarization raida@vut. cz 14
Physical phantoms § Liquid § Solid § Gel § § § Deionized water Agar Polyethylene powder Sodium chloride TX-151 Preservative raida@vut. cz 15
Gel phantoms Component Muscle [g] Brain [g] Deionized water 3375 Agar 104. 6 104, 6 Polyethylene powder 337. 5 548. 1 Sodium chloride 37. 6 21. 5 TX-151 84. 4 57. 1 Sodium azide 2. 0 raida@vut. cz 16
Gel phantoms § On-body communication Modified agar gelatin ( r = 48) - Water: 66% - Agar: 34% Planar horn antenna Mode TE 10 vertical polarization raida@vut. cz 17
Physical phantoms § In-body communication Block with basis 200 mm and height 20 mm raida@vut. cz 18
Physical phantoms § V and W frequency bands J. Láčík, V. Hebelka, J. Vélim, Z. Raida, J. Puskely, Wideband skin-equivalent phantom for V- and W-band. IEEE Antennas and Wireless Propagation Letters, 2016, vol. 15, p. 211– 213 raida@vut. cz 19
Realistic phantoms 3 D scan of human hand R. Vehovský, M. Pokorný, K. Pítra, User hand influence on properties of a dual-band PIFA antenna. Radioengineering, 2014, vol. 23, no. 3, p. 819 -812. raida@vut. cz 20
Realistic phantoms § Rat’s head raida@vut. cz 21
Realistic phantoms raida@vut. cz 22
Phantom calibration § Inhomogeneous tissues represented by a single layer of agar effective parameters § Parameters related to person / body segment / conditions calibration needed § Caliber: analytic model of Norton wave M. Cupal, J. Láčík, M. Mrnka, Z. Raida, J. Vélim, Wireless body area networks: numerical, experimental and approximate characterization. International Conference on Mathematical Methods in Electromagnetic Theory. Lvov (Ukraine): IEEE AP/MTT/ED/AES/GRS/NPS East Ukraine Joint Chapter, 2016. s. 130 -133. raida@vut. cz 23
Phantom calibration § Space wave and surface wave radiated by vertical monopole above perfectly electrically conductive (PEC) plane § Long-distance transmission: space wave prevails raida@vut. cz 24
Phantom calibration § Vertical field component: direct reflected space wave J. C. Jordan, K. G. Balmain, Electromagnetic Waves and Radiating Systems, Englewood Cliffs: Prentice Hall, 1968. raida@vut. cz 25
Phantom calibration § Monopole on tissue: § Where: wave number numerical distance raida@vut. cz 26
Phantom calibration attenuation function complementary error function raida@vut. cz 27
Single-layer phantom f 1 = 5. 4 GHz, f 2 = 5. 8 GHz f 3 = 6. 5 GHz raida@vut. cz 28
Single-layer phantom Transmission between quarter-wavelength monopoles on back of adult man; d = 450 mm. raida@vut. cz 29
Single-layer phantom Reflection coefficient at input of quarter-wavelength monopole raida@vut. cz 30
Single-layer phantom Tuning parameters [ , ] of Norton model: comparison of transmission with voxel model raida@vut. cz 31
Summary § Numerical phantoms: voxel versus layered phantoms § Physical phantoms: agar mixtures and 3 D printing § Phantom calibration raida@vut. cz 32
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