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Electromagnetic Signatures of Human Skin in the Millimeter Wave Band 80-100 GHz

By Amani Yousef Owda, Neil Salmon, and Nacer Ddine Rezgui
Progress In Electromagnetics Research B, Vol. 80, 79-99, 2018


Due to changes in global security requirements attention is turning to new means by which anomalies on the human body might be identified. For security screening systems operating in the millimeter wave band anomalies can be identified by measuring the emissivities of subjects. As the interaction of millimeter waves with the human body is only a fraction of a millimeter into the skin and clothing has a small, but known effect, precise measurement of the emission and reflection of this radiation will allow comparisons with the norm for that region of the body and person category. A technique to measure the human skin emissivity in vivo over the frequency band 80 GHz to 100 GHz is developed and described. The mean emissivity values of the skin of a sample of 60 healthy participants (36 males and 24 females) measured using a 90 GHz calibrated radiometer was found to range from 0.17±0.005 to 0.68±0.005. The lower values of emissivity are a result of measuring particularly thin skin on the inner wrist, volar side of the forearm, and back of hand, whereas higher values of emissivity are results of measuring thick skin on the outer wrist, dorsal surface of the forearm, and palm of hand. The mean differences in the emissivity between Asian and European male participants were calculated to be in the range of 0.04 to 0.11 over all measurement locations. Experimental measurements of the emissivity for male and female participants having normal and high body mass index indicate that the mean differences in the emissivity are in the range of 0.05 to 0.15 for all measurement locations. These results show the quantitative variations in the skin emissivity between locations, gender, and individuals. The mean differences in the emissivity values between dry and wet skin on the palm of hand and back of hand regions were found to be 0.143 and 0.066 respectively. These results confirm that radiometry can, as a non-contact method, identify surfaces attached to the human skin in tens of seconds. These results indicate a route to machine anomaly detection that may increase the through-put speed, the detection probabilities and reduce the false alarm rates in security screening portals.


Amani Yousef Owda, Neil Salmon, and Nacer Ddine Rezgui, "Electromagnetic Signatures of Human Skin in the Millimeter Wave Band 80-100 GHz ," Progress In Electromagnetics Research B, Vol. 80, 79-99, 2018.


    1. Zheng, C., X. Yao, A. Hu, and J. Miao, "A passive millimeter-wave imager used for concealed weapon detection," Progress In Electromagnetics Research B, Vol. 46, 379-397, 2013.

    2. Yang, B.-H., Z.-P. Li, C. Zheng, J. Zhang, X.-X. Yao, A.-Y. Hu, and J.-G. Miao, "Design of a passive millimeter-wave imager used for concealed weapon detection BHU-2D-U," WSEAS Transactions on Circuits and Systems, Vol. 13, 94-103, 2014.

    3. Appleby, R., "Passive millimetre-wave imaging and how it differs from terahertz imaging," Philos. Trans. A Math. Phys. Eng. Sci., Vol. 362, 379-392, 2004, doi:10.1098/rsta.2003.1323.

    4. Harmer, S. W., N. Bowring, D. Andrews, N. D. Rezgui, M. Southgate, and S. Smith, "A review of nonimaging stand-off concealed threat detection with millimeter-wave radar," IEEE Microwave Magazine, Vol. 13, 160-167, 2012, doi:10.1109/MMM.2011.2174125.

    5. Sheen, D. M., D. L. McMakin, and T. E. Hall, "Cylindrical millimeter-wave imaging technique for concealed weapon detection," Proc. SPIE, Vol. 3240, 0000, 1998, doi:10.1117/12.300061.

    6. Salmon, N. A., "Experimental results and simulations from aperture synthesis three-dimensional radiometric imaging," Proc. SPIE, Vol. 9993, 99930B, 2016, doi:10.1117/12.2231696.

    7. Salmon, N. A., "3-D radiometric aperture synthesis imaging," IEEE Transactions on Microwave Theory and Technology, Vol. 63, 3579-3587, 2015, doi:10.1109/TMTT.2015.2481413.

    8. Rezgui, N-D., D. A. Andrews, and N. J. Bowring, "Ultra wide band 3D microwave imaging scanner for the detection of concealed weapons," Proc. SPIE, Vol. 9651, 965108, 2015, doi:10.1117/12.2197581.

    9. Blackhurst, E., N. Salmon, and M. Southgate, "Full polarimetric millimetre wave radar for stand-off security screening," Proc. SPIE, Vol. 10439, 1043906, 2017, doi:10.1117/12.2282564.

    10. Ahmed, S. S., A. Schiessl, F. Gumbmann, M. Tiebout, S. Methfessel, and L.-P. Schmidt, "Advanced microwave imaging," IEEE Microwave Magazine, Vol. 13, 26-43, 2012, doi:10.1109/MMM.2012.2205772.

    11. Ahmed, S. S., O. Ostwald, and L.-P. Schmidt, "Automatic detection of concealed dielectric objects for personnel imaging," Proc. IEEE MTT-S International Microwave Workshop on Wireless Sensing, Local Positioning, and RFID, 1-4, 2009, doi:10.1109/IMWS2.2009.5307899.

    12. Luukanen, A., R. Appleby, M. Kemp, and N. Salmon, Millimeter-Wave and Terahertz Imaging in Security Applications, Vol. 171, Springer, Berlin, Heidelberg, 2012.

    13. Salmon, N. A., "Extended sources near-field processing of experimental aperture synthesis data and application of the Gerchberg method for enhancing radiometric three-dimensional millimetre-wave images in security," Proc. SPIE, Vol. 10439, 1043905, 2017, doi:10.1117/12.2282563.

    14. Salmon, N. A., J. R. Borrill, and D. G. Glee, "Absolute temperature stability of passive imaging radiometers," Proc. SPIE, Vol. 3064, 110-120, 1997, doi:10.1117/12.277072.

    15. Pozar, D. M., Microwave Engineering, 4th Ed., John Wiley & Sons, Hoboken, New Jersey, 2011.

    16. Bardati, F. and D. Solimini, "Radiometric sensing of biological layered media," Radio Science, Vol. 18, 1393-1401, 1983, doi:10.1029/RS018i006p01393.

    17. Owda, A. Y., N. A. Salmon, N.-D. Rezgui, and S. Shylo, "Millimetre wave radiometers for medical diagnostics of human ski," Proc. IEEE Sensors, 1-3, 2017.

    18. Harmer, S. W., S. Shylo, M. Shah, N. J. Bowring, and A. Y. Owda, "On the feasibility of assessing burn wound healing without removal of dressings using radiometric millimetre-wave sensing," Progress In Electromagnetics Research M, Vol. 45, 173-183, 2016.

    19. Owda, A. Y., N. Salmon, S. W. Harmer, S. Shylo, N. J. Bowring, N. D. Rezgui, and M. Shah, "Millimeter-wave emissivity as a metric for the non-contact diagnosis of human skin conditions," Bioelectromagnetics, Vol. 38, 559-569, 2017, doi:10.1002/bem.22074.

    20. Feldman, Y., A. Puzenko, P. Ben Ishai, A. Caduff, and A. J. Agranat, "Human skin as arrays of helical antennas in the millimeter and submillimeter wave range," Physical Review Letters, Vol. 100, 128102, 2008, doi:https://doi.org/10.1103/PhysRevLett.100.128102.

    21. Feldman, Y., A. Puzenko, P. Ben Ishai, A. Caduff, I. Davidovich, F. Sakran, and A. J. Agranat, "The electromagnetic response of human skin in the millimetre and submillimetre wave range," Physics in Medicine & Biology, Vol. 54, 3341-3363, 2009, doi:https://doi.org/10.1088/00319155/54/11/005.

    22. Smulders, P. M. F., "Analysis of human skin tissue by millimeter-wave reflectometry," Skin Research and Technology, Vol. 19, e209-e216, 2012, doi:10.1111/j.1600-0846.2012.00629.x.

    23. Owda, A. Y., N.-D. Rezgui, and N. A. Salmon, "Signatures of human skin in the millimetre wave band (80–100) GH," Proc. SPIE, Vol. 10439, 1043904, 2017, doi:10.1117/12.2292046.

    24. Kuchler, N., D. D. Turner, U. Lohnert, and S. Crewell, "Calibrating ground-based microwave radiometers: Uncertainty and drifts," Radio Science, Vol. 51, 311-327, 2016, doi:10.1002/2015RS005826.

    25. Salmon, N. A., L. Kirkham, and P. N. Wilkinson, "Characterisation and calibration of a large aperture (1.6 m) ka-band indoor passive millimeter wave security screening imager," Proc. SPIE, Vol. 8544, 854408, 2012, doi:10.1117/12.999278.

    26. Lee, Y. and K. Hwang, "Skin thickness of Korean adults," Surgical and Radiologic Anatomy, Vol. 24, 183-189, 2002, doi:10.1007/s00276-002-0034-5.

    27. Gray, H., Anatomy of the Human Body, Lea & Febiger, Hiladelphia, Pennsylvania, 1981.

    28. McGrath, J. A. and J. Uitto, "Rook's Textbook of Dermatology," Wiley-Blackwell, 2016.

    29. Zhadobov, M., N. Chahat, R. Sauleau, C. L. Quement, and Y. L. Drean, "Millimeterwave interactions with the human body: State of knowledge and recent advances," International Journal of Microwave and Wireless Technologies, Vol. 3, 237-247, 2011, doi:https://doi.org/10.1017/S1759078711000122.

    30. Alekseev, S. I., I. Szabo, and M. C. Ziskin, "Millimeter wave reflectivity used for measurement of skin hydration with different moisturizers," Skin Research and Technology, Vol. 14, 390-396, 2008, doi:10.1111/j.1600-0846.2008.00319.x.

    31. Giacomoni, P. U., T. Mammone, and M. Teri, "Gender-linked differences in human skin," Journal of Dermatological Science, Vol. 55, 144-149, 2009, doi: https://doi.org/10.1016/j.jdermsci.2009.06.001.

    32. Sandby-Møller, J., T. Poulsen, and H. C. Wulf, "Epidermal thickness at different body sites: Relationship to age, gender, pigmentation, blood content, skin type and smoking habits," Acta Derm Venereol, Vol. 83, 410-413, 2003, doi:10.1080/00015550310015419.

    33. Shuster, S., M. M. Black, and E. Mcvitie, "The influence of age and sex on skin thickness, skin collagen and density," Br. J. Dermatol., Vol. 93, 639-643, 1975, doi:10.1111/j.1365-2133.1975.tb05113.x.

    34. Rawlings, A. V., "Ethnic skin types: Are there differences in skin structure and function?," International Journal of Cosmetic Science, Vol. 28, 79-93, 2006, doi:10.1111/j.1467-2494.2006.00302.x.

    35. Sugino, K., G. Imokawa, and H. I. Maibach, "Ethnic difference of varied stratum corneum function in relation to stratum corneum lipids," Journal of Dermatological Science, Vol. 6, 108, 1993, doi: https://doi.org/10.1016/0923-1811(93)91343-S.

    36. Hillebrand, G. G., M. J. Levine, and K. Shigaki-Miyamoto, "The age dependent changes in skin condition in African Americans, Asian Indians, Caucasians, East Asians & Latinos," IFSCC Magazine, Vol. 4, 259-266, 2001.

    37. Williams, G. F., "Microwave emissivity measurements of bubbles and foam," IEEE Trans. Geosci. Elect., Vol. 9, 221-224, 1971, doi: 10.1109/TGE.1971.271504.

    38. Rose, L. A., W. E. Asher, S. C. Reising, P. W. Gaiser, K. M. St Germain, D. J. Dowgiallo, K. A. Horgan, G. Farquharson, and E. J. Knapp, "Radiometric measurements of the microwave emissivity of foam," IEEE Trans. Geosci. Remote Sens., Vol. 40, 2619-2625, 2002, doi: 10.1109/TGRS.2002.807006.

    39. Derraik, J. G. B., M. Rademaker, W. S. Cutfield, T. E. Pinto, S. Tregurtha, A. Faherty, J. M. Peart, P. L. Drury, and P. L. Hofm, "Effects of age, gender, BMI, and anatomical site on skin thickness in children and adults with diabetes," PLoS ONE, Vol. 9, e86637, 2014, doi: https://doi.org/10.1371/journal.pone.0086637.

    40. Jackson, A. S., P. R. Stanforth, J. Gagnon, T. Rankinen, A. S. Leon, D. C. Rao, J. S. Skinner, C. Bouchard, and J. H. Wilmore, "The effect of sex, age and race on estimating percentage body fat from body mass index: The Heritage Family Study," International Journal of Obesity, Vol. 26, 789-796, 2002, doi:10.1038/sj.ijo.0802006.

    41. Alekseev, S. I. and M. C. Ziskin, "Human skin permittivity determined by millimeter wave reflection measurements," Bioelectromagnetics, Vol. 28, 331-339, 2007, doi: 10.1002/bem.20308.

    42. Egot-Lemaire, S. J.-P. and M. C. Ziskin, "Dielectric properties of human skin at an acupuncture point in the 50–75 GHz frequency range. A pilot study," Bioelectromagnetics, Vol. 32, 360-366, 2011, doi: 10.1002/bem.20650.

    43. 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.

    44. Gabriel, S., R. W. Lau, and C. Gabriel, "The dielectric properties of biological tissues: II. Measurements in the frequency range 10Hz to 20 GHz," Physics in Medicine and Biology, Vol. 41, 2251-2269, 1996.

    45. Wallace, V. P., J. Fitzgerald, S. Shankar, N. Flanagan, R. Pye, J. Cluff, and D. D. Arnone, "Terahertz pulsed imaging of basal cell carcinoma ex vivo and in vivo," British Journal Dermatology, Vol. 151, 424-432, 2004, doi:10.1111/j.1365-2133.2004.06129.x.