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    Öğe
    Measuring and modelling the complex-permittivity of hemp plant (Cannabis Sativa) at X band for microwave remote sensing
    (Taylor & Francis Ltd, 2021) Genc, Abdullah; Basyigit, I. Bahadir; Dogan, Habib; Colak, Bektas
    It is vital to determine the dielectric characterization of hemp plant (Cannabis Sativa) for microwave remote sensing to increase its accuracy and to improve algorithms for satellite data interpretation. For that, this study provides the measurement results of complex permittivity of hemp stems and leaves in terms of various moisture contents (MC) in 8-12.4 GHz in a laboratory with a temperature of 25 degrees C and a relative humidity of 59%. With the measurement data, the dielectric properties are modelled as a second-order polynomial function based on a curve-fitting method depending on the frequency and MC. For hemp stems and leaves with various MC, while the real part of the relative complex permittivity (epsilon ') ranges between 2.1-7.2 and 1.5-6.1, the imaginary part of that (epsilon '') varies in 0.3-4.5 and 0.2-4.2, respectively. The measured and modelled results are compatible with each other.
  • [ X ]
    Öğe
    Scalar Dielectric Constant Extraction of Planar Materials from Reflection Measurements
    (2020) Colak, Bektas
    Industrial plastics are widely used in warfare electromechanical systems to protect the internal electroniccircuitry from environmental effects. Depending the purpose of the warfare system, the surface interactionwith electromagnetic fields play a key role and the main parameter that determines reflection and the shieldingof the electromagnetic fields from material surface is the dielectric constant of the material itself. In this paper,extraction of scalar dielectric constant from electromagnetic reflection measurement using an alternative twostandard calibration technique in a low cost aluminum compact chamber is obtained. Calibration techniqueuses time domain measurements and converts them to frequency domain. Especially in R&D phase ofelectromechanical integration of warfare systems, this technique is quite useful where the exact values ofdielectric constants of planar industrial plastics are not required. Obtained reflection coefficient error level is0.67dB for 10mm while it reaches 1.62dB for 40mm thickness materials. It is shown that calculated values are ingood agreement with the reference measurement method performed by precision airline setup Agilent 85050C.