Efficient Time-Domain Multi-Channel Measurements using a Multi-Axis Antenna for Frequency Range below 30 MHz

2021 ◽  
Author(s):  
Denys Pokotilov ◽  
Robert Vogt-Ardatjew ◽  
Frank Leferink
Keyword(s):  
Time Domain ◽  
Channel Measurements ◽  
Frequency Range

scholarly journals A Comparison of Time-Domain Implementation Methods for Fractional-Order Battery Impedance Models

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4415
Author(s):  
Brian Ospina Agudelo ◽  
Walter Zamboni ◽  
Eric Monmasson
Keyword(s):  
Fractional Order ◽  
Time Domain ◽  
Li Ion Batteries ◽  
Simulation Framework ◽  
Frequency Range ◽  
Interesting Approach ◽  
Li Ion ◽  
Impedance Parameters ◽  
Impedance Models ◽  
Made In

This paper is a comparative study of the multiple RC, Oustaloup and Grünwald–Letnikov approaches for time domain implementations of fractional-order battery models. The comparisons are made in terms of accuracy, computational burden and suitability for the identification of impedance parameters from time-domain measurements. The study was performed in a simulation framework and focused on a set of ZARC elements, representing the middle frequency range of Li-ion batteries’ impedance. It was found that the multiple RC approach offers the best accuracy–complexity compromise, making it the most interesting approach for real-time battery simulation applications. As for applications requiring the identification of impedance parameters, the Oustaloup approach offers the best compromise between the goodness of the obtained frequency response and the accuracy–complexity requirements.

scholarly journals Propagation Channel Measurements in the mm- and Sub-mm Wave Range for Different Indoor Communication Scenarios

2021 ◽  
Vol 42 (4) ◽  
pp. 357-370
Author(s):  
M. A. Salhi ◽  
T. Kleine-Ostmann ◽  
T. Schrader
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Wireless Communication Systems ◽  
Electromagnetic Spectrum ◽  
Channel Measurements ◽  
Frequency Range ◽  
Propagation Channel ◽  
Data Rates ◽  
Indoor Wireless ◽  
Wave Range

AbstractIncreasing data rates in wireless communications are accompanied with the need for new unoccupied and unregulated bandwidth in the electromagnetic spectrum. Higher carrier frequencies in the lower THz frequency range might offer the solution for future indoor wireless communication systems with data rates of 100 Gbit/s and beyond that cannot be located elsewhere. In this review, we discuss propagation channel measurements in an extremely broad frequency range from 50 to 325 GHz in selected indoor communication scenarios including kiosk downloading, office room communication, living rooms, and typical industrial environments.

Properties of Bi and BiSb Nano-Dimensional Layers in Thz Frequency Range

2020 ◽  
Vol 312 ◽  
pp. 206-212
Author(s):  
Ivan L. Tkhorzhevskiy ◽  
Anton D. Zaitsev ◽  
Petr S. Demchenko ◽  
Dmitry V. Zykov ◽  
Aleksei V. Asach ◽  
...  
Keyword(s):  
Phase Shift ◽  
Time Domain ◽  
Terahertz Wave ◽  
Film Structure ◽  
Charge Carriers ◽  
Frequency Range ◽  
Terahertz Time Domain Spectroscopy ◽  
Antimony Content ◽  
Mobility Of Charge Carriers ◽  
Substrate Film

In the present paper we demonstrate and compare different properties of Bi and Bi1-xSbx thin films placed on polyimide (PI) substrate in frequency range from 0.2 to 1.0 THz. Bi films with a thickness of 40, 105 and 150 nm have been studied as well as 150 nm Bi1-xSbx solid solutions with Sb concentration of 5, 8, 12 and 15 %. An effective refractive index and permittivity of whole substrate/film structures have been derived by using terahertz time-domain spectroscopy (THz-TDS) method. These measurements have shown the positive phase shift in PI substrate with a thickness of 42 μm and revealed that it is barely transparent in studied frequency range, but the whole substrate/film structure provides the negative phase shift of terahertz wave. It was shown that the permittivity depends on mobility of charge carriers which is driven by film thickness and antimony content.

scholarly journals Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix

2019 ◽  
Vol 9 (3) ◽  
pp. 391 ◽  
Author(s):  
Anton Koroliov ◽  
Genyu Chen ◽  
Kenneth M. Goodfellow ◽  
A. Nick Vamivakas ◽  
Zygmunt Staniszewski ◽  
...  
Keyword(s):  
Polymer Matrix ◽  
Time Domain ◽  
Thz Radiation ◽  
Complex Conductivity ◽  
Frequency Range ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Graphene Nanocomposites ◽  
Graphene Nanoflakes ◽  
Exfoliated Graphene

The terahertz time-domain spectroscopy (THz-TDS) technique has been used to obtain transmission THz-radiation spectra of polymer nanocomposites containing a controlled amount of exfoliated graphene. Graphene nanocomposites (1 wt%) that were used in this work were based on poly(ethylene terephthalate-ethylene dilinoleate) (PET-DLA) matrix and were prepared via a kilo-scale (suitable for research and development, and prototyping) in-situ polymerization. This was followed by compression molding into 0.3-mm-thick and 0.9-mm-thick foils. Transmission electron microscopy (TEM) and Raman studies were used to confirm that the graphene nanoflakes dispersed in a polymer matrix consisted of a few-layer graphene. The THz-radiation transients were generated and detected using a low-temperature–grown GaAs photoconductive emitter and detector, both excited by 100-fs-wide, 800-nm-wavelength optical pulses, generated at a 76-MHz repetition rate by a Ti:Sapphire laser. Time-domain signals transmitted through the nitrogen, neat polymer reference, and 1-wt% graphene-polymer nanocomposite samples were recorded and subsequently converted into the spectral domain by means of a fast Fourier transformation. The spectral range of our spectrometer was up to 4 THz, and measurements were taken at room temperature in a dry nitrogen environment. We collected a family of spectra and, based on Fresnel equations, performed a numerical analysis, that allowed us to extract the THz-frequency-range refractive index and absorption coefficient and their dependences on the sample composition and graphene content. Using the Clausius-Mossotti relation, we also managed to estimate the graphene effective dielectric constant to be equal to ~7 ± 2. Finally, we extracted from our experimental data complex conductivity spectra of graphene nanocomposites and successfully fitted them to the Drude-Smith model, demonstrating that our graphene nanoflakes were isolated in their polymer matrix and exhibited highly localized electron backscattering with a femtosecond relaxation time. Our results shed new light on how the incorporation of exfoliated graphene nanoflakes modifies polymer electrical properties in the THz-frequency range. Importantly, they demonstrate that the complex conductivity analysis is a very efficient, macroscopic and non-destructive (contrary to TEM) tool for the characterization of the dispersion of a graphene nanofiller within a copolyester matrix.

FHS Semi: A Semisubmersible Design for Dry Tree Applications

2009 ◽  
Author(s):  
Alaa M. Mansour
Keyword(s):  
Gulf Of Mexico ◽  
Water Depth ◽  
Time Domain ◽  
Frequency Range ◽  
Integration Technique ◽  
Natural Period ◽  
Ballast Tank ◽  
New Feature ◽  
Fully Coupled

In this paper the performance of a new conceptual semisubmersible design that provides motion response similar to a Spar is investigated. The new invention introduces a new feature which is the Free-Hanging Solid Ballast Tank, hence the name FHS Semi. The use of the free-hanging Solid Ballast Tank (SBT) significantly increases the heave natural period while controlling the heave response in the wave frequency range and, therefore, enables the use of the FHS Semi in dry tree applications. The new design’s quayside integration technique and its interface with the top tensioned risers are presented in this paper. Case study for the new design to support a 32,000 ST payload including 15 Top Tensioned Risers (TTRs) in an ultra-deepwater of 8,000 ft water depth is considered. Frequency domain and fully coupled time-domain hydrodynamic analyses have been performed and numerical results are presented to illustrate the new semisubmersible design response in extreme Gulf of Mexico hurricane events.

FABRICATION AND CHARACTERIZATION OF BROADBAND TERAHERTZ WIRE-GRID POLARIZER

2010 ◽  
Vol 19 (04) ◽  
pp. 827-833 ◽  
Author(s):  
Z. C. CHEN ◽  
M. H. HONG ◽  
T. C. CHONG
Keyword(s):  
Time Domain ◽  
Quartz Substrate ◽  
Terahertz Wave ◽  
Mean Value ◽  
Frequency Range ◽  
Terahertz Time Domain Spectroscopy ◽  
Free Standing ◽  
Wire Grid ◽  
The Wire ◽  
Wire Grid Polarizer

A wire-grid terahertz polarizer fabricated on quartz substrate working in broadband is demonstrated. The transmission spectra of the fabricated wire-grid polarizer are characterized by terahertz time domain spectroscopy, showing the good performance of this polarizer in the terahertz frequency range up to 3.5 THz. The transmission of the peak in the time domain is 80% when the incident terahertz wave polarization is perpendicular to the wire-grid. The transmission of the peak is lower than 10% when the incident polarization is parallel to the wire-grid. The polarization factor ranges from 0.92–0.99 with the mean value of 0.97 in the frequency range from 0.1 to 3.5 THz, which is better than that of the free-standing wire-grid polarizer.

scholarly journals Mid Frequency Shock Response Determination by Using Energy Flow Method and Time Domain Correction

2013 ◽  
Vol 20 (5) ◽  
pp. 847-861 ◽  
Author(s):  
Sung-Hyun Woo ◽  
Jae-Hung Han
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Time Domain ◽  
Energy Flow ◽  
Practical Method ◽  
Frequency Range ◽  
Element Analysis ◽  
Flow Method ◽  
Force Signal ◽  
Structural Parts

Shock induced vibration can be more crucial in the mid frequency range where the dynamic couplings with structural parts and components play important roles. To estimate the behavior of structures in this frequency range where conventional analytical schemes, such as statistical energy analysis (SEA) and finite element analysis (FEA) methods may become inaccurate, many alternative methodologies have been tried up to date. This study presents an effective and practical method to accurately predict transient responses in the mid frequency range without having to resort to the large computational efforts. Specifically, the present study employs the more realistic frequency response functions (FRFs) from the energy flow method (EFM) which is a hybrid method combining the pseudo SEA equation (or SEA-Like equation) and modal information obtained by the finite element analysis (FEA). Furthermore, to obtain the time responses synthesized with modal characteristics, a time domain correction is practiced with the input force signal and the reference FRF on a position of the response subsystem. A numerical simulation is performed for a simple five plate model to show its suitability and effectiveness over the standard analytical schemes.

Finite-Difference Time-Domain Simulation of Microwave Sintering in A Variable-Frequency Multimode Cavity

1996 ◽  
Vol 430 ◽  
Author(s):  
Mikel J White ◽  
Steven F. Dillon ◽  
Magdy F. Iskander ◽  
Hal D. Kimrey
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Microwave Sintering ◽  
Single Frequency ◽  
Frequency Variation ◽  
Variable Frequency ◽  
Frequency Range ◽  
Fdtd Simulations ◽  
Difference Time

AbstractThere have been recent indications that variable-frequency microwave sintering of ceramics provides several advantages over single-frequency sintering, including more uniform heating, particularly for larger samples. The Finite-Difference Time-Domain (FDTD) code at the University of Utah was modified and used to simulate microwave sintering using variable frequencies and was coupled with a heat-transfer code to provide a dynamic simulation of this new microwave sintering process. This paper summarizes results from the FDTD simulations of sintering in a variable-frequency cavity. FDTD simulations were run in 100-MHz steps to account for the frequency variation in the electromagnetic fields in the multimode cavity. It is shown that a variable-frequency system does improve the heating uniformity when the proper frequency range is chosen. Specifically, for a single ceramic sample (4 × 4 × 6 cm3), and for a variable-frequency range from f = 2.5 GHz to f = 3.2 GHz, the temperature distribution pattern was much more uniform than the heating pattern achieved when using a single-frequency sintering system at f = 2.45 GHz.

scholarly journals Ultra Wideband Coplanar Waveguide Antenna with an Improved Gain using a Frequency Selective Surfaces (FSS)

2019 ◽  
Vol 8 (9S) ◽  
pp. 145-149
Keyword(s):  
Time Domain ◽  
Coplanar Waveguide ◽  
Unit Cell ◽  
Ultra Wideband ◽  
Frequency Range ◽  
Rectangular Slot ◽  
Improved Performance ◽  
Set Up ◽  
The Time Domain ◽  
Uwb Applications

In this article, an ultra-wideband FSS reflector has been proposed to enhance the gain of a CPW antenna for UWB applications. A CPW fed antenna having dimensions of 38mm×38mm×1.605mm and FSS unit cell having dimensions 14mm × 14mm × 1.605 mm are presented in the paper. A rectangular slot and stubs are interleaved at the outer edges of the patch for achieving desired characteristics of an ultra-wideband for the frequency range of 3.39 GHz to 12.9 GHz. Simulation results carried out using the CST microwave 2016 version in the time domain are presented for the proposed antenna. An FSS unit cell designed and simulated using periodic boundary conditions and floquet ports is presented. The combined setup of an array of FSS reflector behind the antenna has been simulated in the time domain. This set up shows an improved performance in terms of antenna’s gain. A maximum and minimum gain of 8.14 dB and 4.98 dB has been observed with the presence of FSS reflector behind the coplanar waveguide antenna. A significant improvement of 2.9 dB has been observed over the entire band of antenna’s operation

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