Serwis Infona wykorzystuje pliki cookies (ciasteczka). Są to wartości tekstowe, zapamiętywane przez przeglądarkę na urządzeniu użytkownika. Nasz serwis ma dostęp do tych wartości oraz wykorzystuje je do zapamiętania danych dotyczących użytkownika, takich jak np. ustawienia (typu widok ekranu, wybór języka interfejsu), zapamiętanie zalogowania. Korzystanie z serwisu Infona oznacza zgodę na zapis informacji i ich wykorzystanie dla celów korzytania z serwisu. Więcej informacji można znaleźć w Polityce prywatności oraz Regulaminie serwisu. Zamknięcie tego okienka potwierdza zapoznanie się z informacją o plikach cookies, akceptację polityki prywatności i regulaminu oraz sposobu wykorzystywania plików cookies w serwisie. Możesz zmienić ustawienia obsługi cookies w swojej przeglądarce.
Since radar absorbing structures function simultaneously as electromagnetic waves absorbing and load bearing structures, many structural elements such as horizontal and vertical stabilizers, wing skins, fuselage, and various structural elements can be replaced with radar absorbing structures to reduce the radar cross section (RCS). The key design parameters of radar absorbing structure are the thickness...
In this study, an iterative inversion algorithm for the determination of complex dielectric permittivity of non-magnetic, isotropic materials is presented. The dielectric sample to be measured is considered to load a rectangular waveguide partially. The inversion method is based on a fit between simulated and measured scattering parameters by Newton's technique. In order to obtain the simulated scattering...
This paper presents results of a study on multi-layer binomial radar absorbers constructed from rubber latex using coconut shells as fillers. The microwave properties of the absorbers were measured using a microwave non-destructive testing (MNDT) technique. The performance of single layer, two-layer and three-layer absorbers were simulated using a commercial 3D electromagnetic simulator. Single layer...
This paper presents experimental results of our study on multi-layer microwave absorbers synthesized using coconut shells as the source of activated carbon. In this investigation, activated carbon with content variation of 0, 10, 15, 20, 25 and 30 wt% were mixed with Flaxane-80 to study the microwave properties of the absorbers. Three- and four-layer microwave absorbers with various carbon contents...
Ground penetrating radar (GPR) is widely used in subsurface utility mapping for extracting the position (x, y) and depth (z) information of the utility. This information is crucial for subsurface facility management, in particular as reference in excavation works. The locational and depth information of the utility features is therefore of very important in subsurface mapping, apart from the reliability...
Reflectarray antennas provide a low cost, low volume and low profile way for different type of applications but due to limited phase ranges and high reflection loss performance their use is limited in the field of satellite and earth observatory systems. In this paper a rectangular patch reflectarray operating at 10 GHz constructed on 1mm thick isotropic and anisotropic substrates is proposed to be...
This paper is part of a larger project which aims to investigate the fabricational and electromagnetic advantages of creating integrated antenna systems using emerging nano-manufacturing technology. It has been known for several decades that the effective permittivity of a mixture consisting of dielectric inclusions in a host dielectric can be controlled by varying the permittivity, size and spacing...
In this paper, a hemispherical open resonator is used to measure the quality factor and resonant frequency of various materials in the millimeter wave band. This measurement method allows us to determine the permittivity and the loss tangent of homogeneous materials. Materials like PTFE, PE and PS were used to validate the measurement system. Finally, we measured the resonant frequency and quality...
Delay time measurements, e.g. time domain reflectometry (TDR), are a well-established method for the measurement of permittivity in various materials, especially in soils. However, the accuracy offered by common TDR measurements is limited due to multiple reflections caused by the material under test. This contribution deals with new sensor designs for the characterization of soil moisture using time...
Progress in Microelectronics and Nanotechnology is determined by advancement in developing and characterization of novel materials. In this paper recent developments in non-destructive measurements of high quality semiconductors, conducting polymers, graphene and metamaterials are presented.
Polymer insulating materials installed in electronic and electrical devices have been used in space equipment and nuclear power station where the materials are exposed to high energetic radioactive rays. The molecular structure can be changed by radiation induced chemical reactions that possibly lead to the variation of characteristics of surface charge dynamics, which in turn influences the safe...
The main objective of this paper is to give an electrical characterization of epoxy based nanocomposite materials. These innovative materials are composed of an cycloaliphatic epoxy with a flexibiliser mixed with 0, 1, and 20%wt Nanopox®. These materials are aimed to be used for electrical engineering applications and they should have a significant increase in electrical performances compared to the...
Relative permittivity characterization of foliage is important in microwave system modeling and planning, especially in forest area. However, there is a difficulty in the characterization unless the foliage has to be formed so that its dimension is small enough compared to the measurement tool such as waveguide. This problem is encountered in the cavity perturbation method. Another method, for instance...
This paper explains in details the NRW method highlighting its mathematical procedure and analyzing the most important points and limitations to characterize the complex permittivity and permeability of dielectrics. The step by step procedure help the researchers to well understand the physical phenomenona involved and also is a tool to facilitate its implementation. Explanations on the limitations...
The constitutive parameters of a Teflon sample of arbitrary thickness are retrieved from scattering parameters experimentally measured with a vector network analyzer and a waveguide system into which the test sample is inserted by filling the transverse section of the X-band waveguide. Based on the Nicolson-Ross-Weir (NRW) method and modified to eliminate the phase ambiguity inherent to the NRW procedure,...
A study of the effect of the presence of Y3Fe5O12 (YIG) in the dielectric properties of the CaCu3Ti4O12 (CCTO) is presented. The samples were prepared by the solid state method. Mechanical alloying followed by the solid state procedure had been successfully used to produce powders of CCTO and YIG to be used in the composites. We also look at the effect of the grain size of the YIG and CCTO in the...
Accurate measurement of dielectric properties of granular materials and powders is important in material science, pharmacology, agriculture, and other fields. Granular materials present a wide range of measurement challenges not encountered with solid and liquid samples. This paper presents the calibration process for measurement of granular material properties using a custom-designed dielectric spectroscopy...
Accurate material modeling is an important factor in simulation of dispersive materials. We present different dispersive models for the simulation of dispersive materials, and can be used from microwave to optical frequencies depending on the nature of application. Most of available dispersive models are in frequency domain, to make them consistent with time domain methods; different approaches are...
In this paper, properties of artificially-designed materials and their applications in electromagnetic (EM) wave absorber are discussed. First, EM-wave absorber composed of the straight length wire array sheet and a ferrite-powder/rubber mixture plate is investigated. The absorbing characteristics of the absorber using the wire array sheet can be matched at around the resonant frequency of the sheet...
The capacitive touch sensor measure the value changes of capacitance. The changes were sent to MCU after they were sensed by the analog hardware. Add periodic charging voltage to RC network. The terminal voltage of capacitance in the RC network will fall off in the settled charging time because of the change of permittivity in the network caused by finger touching activity. We can judge whether the...
Podaj zakres dat dla filtrowania wyświetlonych wyników. Możesz podać datę początkową, końcową lub obie daty. Daty możesz wpisać ręcznie lub wybrać za pomocą kalendarza.