M Saviz

University of Tehran, Teheran, Tehrān, Iran

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Publications (8)2.81 Total impact

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    ABSTRACT: The dielectric properties of biological tissues and their substructures at terahertz frequencies are needed for computational dosimetry, radiation safety regulation, and medical imaging, but experimental tissue data are only scarcely available for the terahertz band. Tissue properties can be theoretically predicted at terahertz frequencies if the tissue microstructure and composition, and the dielectric properties of several basic biological materials are known. This paper introduces a new open-source toolbox where a material database and many of the relevant formulas are implemented to facilitate related research. Several examples have been analyzed and successfully verified with experimental data from the literature.
    Journal of infrared, millimeter and terahertz waves 07/2013; 34(7-8):529-538. · 1.12 Impact Factor
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    ABSTRACT: This paper contributes to the topic of radiation safety in the THz band by providing theoretical estimations of the permissible incident power densities over 100 GHz – 10 THz. Microthermal absorption has been characterized and a worstcase analysis has been done to provide thresholds for the tissueinternal electric field strength at THz frequencies. Dielectric models for the skin and the cornea of the eye as exposed surface tissues have been constructed and used to estimate the corresponding thresholds for incident power densities. The findings of this study shall be useful as a new theoretical framework for future studies related to THz radiation safety and regulation.
    IEEE Transactions on Terahertz Science and Technology. 06/2013; 3(5):635-640.
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    ABSTRACT: The number of current applications in the THz-frequency range (0.1-10 THz), e.g. full-body scanners or WLAN communication technologies, is rapidly rising. Accordingly, the need for methods to determine the risk for the general public and for employees due to electromagnetic exposure from such sources is growing. The currently available literature provides only information about dielectric material properties of biological tissues for frequencies below 100 GHz. For higher frequencies, the knowledge is sparse. The “effective medium theory” is applied here to estimate the required material data above 100 GHz, which are obviously needed for numerical dosimetry purposes in the THz range. These data are used subsequently for numerical computations of electromagnetic THz-fields in human tissues and resulting heat elevations.
    EMC Europe 2013, Brugge, Belgium, 02.-06.09.2013; 01/2013
  • Joint Meeting of The Bioelectromagnetics Society (BEMS) and the European BioElectromagnetics Association (EBEA) (BioEM 2013), Thessaloniki, Greece, 10.06.-14.06.2013; 01/2013
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    ABSTRACT: In order to develop computational methods for determining the reaction of biological systems exposed to THz radiation, conventional approaches of numerical dosimetry have to be extended. The penetration depth of electromagnetic fields at THz frequencies is less than 1 mm and thus substantially smaller than for radio frequencies. In addition, the short wavelengths in this frequency range cause the necessity of high resolution models. Here, a selection of simulation models of the human skin and of the eye as well as of the excitation field are presented together with a proposal to assess the appropriate dielectric tissue parameters.
    International Symposium on Electromagnetic Compatibility (EMC Europe 2012), Rom, Italy, 17.-21.09.2012; 09/2012
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    ABSTRACT: We report a novel tilting exposure photolithography (TEL) technique where gradual pattern displacement is employed to achieve high-resolution features over large areas with reasonable exposure times. A linear array with features of the order of 100 nm has been realized using this technique with standard blue-light LED sources. TEL can be useful in the visible and ultraviolet spectra to create two-dimensional periodic structures. The created structures include the nanometric array of spots and lines. The proposed technique can be used as a writing method where complex features can be generated by moving the sample-holding leading to serpentine nanometric linear arrays.
    Applied Optics 06/2012; 51(16):3329-37. · 1.69 Impact Factor
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    ABSTRACT: After discovering drawbacks of current similar methods of cell exposure, a new approach towards such setup was taken by examining the possibility of using a grounded Coplanar-Waveguide (C.P.W) with a different substrate to make the near-perfect line matching possible for intended frequencies. A considerable size reduction was also achieved and holes were considered for simultaneous microscopy. Specific Absorption Rate (SAR) and temperature change in the biological sample were then computed and compared with standards to investigate compatibility with bioelectromagnetic requirements. Finally, the radiated fields of such setup were measured and compared with safety standards to ensure operator safety.
    Electrical Engineering (ICEE), 2011 19th Iranian Conference on; 06/2011
  • M. Saviz, R. Faraji-Dana
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    ABSTRACT: In this paper the reduction of the area allocated to the filtering functionality in planar circuit design is discussed. A space-saving structure has been considered, featuring several tunable parameters that are adjusted using particle swarm optimization. The results indicate the possibility of achieving the design goals while saving space for other circuit elements.