Analytical Uncertainty Evaluation of Material Parameter Measurements at THz Frequencies
- PDF / 2,924,152 Bytes
- 19 Pages / 439.642 x 666.49 pts Page_size
- 76 Downloads / 201 Views
Analytical Uncertainty Evaluation of Material Parameter Measurements at THz Frequencies Alireza Kazemipour1 · Michael Wollensack1 · Johannes Hoffmann1 · 1 · Daniel Stalder1 · ¨ Rufenacht ¨ Martin Hudliˇcka2 · See-Khee Yee3 · Jurg 1 1 ¨ Gregory Gaumann · Markus Zeier Received: 14 April 2020 / Accepted: 11 June 2020 / © The Author(s) 2020
Abstract Material parameter extraction algorithms are studied and simplified both for transmission-reflection and transmission-only methods. The simplified relations, which are closed-form in some cases, are analyzed to establish the uncertainty sensitivity coefficients and therefore, to clarify the main uncertainty contributions and reduce the systematic and random errors. Simple closed-form expressions presented in this paper show the sensitivity of the extracted permittivity to each input parameter such as S21 (phase and amplitude), frequency, and the material thickness. Results are presented for several material slabs for three waveguide frequency ranges 75– 110 GHz, 140–220 GHz, and 500–750 GHz using VNA-based free-space technique in the THz domain. Comparison of results (and the associated uncertainties) between different algorithms can help to choose the optimal one suitable for lossy or lowloss materials, and thin or thicker slabs. This can explain why the same set of S-parameters data usually gives different final results (permittivity and permeability) with different algorithms and verify the reliability of the calibration and extraction process. Keywords Material characterization · Extraction method · THz domain · Sensitivity coefficient · Measurement uncertainty · RF metrology
Alireza Kazemipour
[email protected] 1
Swiss Federal Institute of Metrology (METAS), Lindenweg 50, 3003, Bern-Wabern, Switzerland
2
Department of Primary Metrology of RF Electrical Quantities, Czech Metrology Institute, Radiov´a 3, 10200, Prague, Czech Republic
3
Research Center for Applied Electromagnetics, University Tun-H Malaysia (UThM), 86400, Johor, Malaysia
International Journal of Infrared and Millimeter Waves
1 Introduction Measurement of complex permittivity and permeability is very important in THz and millimeter-wave technology (substrates and dielectric components), biomedical and space applications, material engineering, and others. There exist different measurement techniques for different frequency ranges and materials which can cover lossy to low-loss slabs with various sizes and thicknesses [1]. Closed and open transmission cells and waveguides [2] or resonant cavities [3] are usually used in the microwave region. Waveguide or cavity methods, however, seem to be less applicable in the mmWave/THz domain because of mechanical problems and dimensional restrictions. Free-space non-contact methods are therefore used largely at these frequencies [4, 5]. Laser-based optical techniques have been, for a long time, the only solution for THz spectroscopy [6, 7], but recent progress in high-frequency semiconductor technology made available electronic-based components in
Data Loading...
