scholarly journals A review of modern materials used in military camouflage within the radar frequency range

2021 ◽  
pp. 1-9
Author(s):  
Bogusława Szczodrowska ◽  
Robert Mazurczuk
Keyword(s):  
Frequency Range ◽  
Materials Used ◽  
Radar Frequency

The article presents an overview of materials which can be employed used to camouflage objects on the modern battlefield in the radar frequency range.

Three-layer Permutation of the Phonionic Structure and the Influence of the Environment

2018 ◽  
Vol 69 (9) ◽  
pp. 2571-2574
Author(s):  
Michal Szota
Keyword(s):  
Layer Structure ◽  
Middle Layer ◽  
Production Costs ◽  
Frequency Range ◽  
Different Types ◽  
Transmission Structure ◽  
Materials Used ◽  
The Impact ◽  
Wave Filters ◽  
Different Thickness

The study investigated the influence of permutation of a three-layer structure on the phononic system transmission. Phononic structures are used as mechanical wave filters. These composites are designed and manufactured to have specific properties. The most important property is the presence of phononic bandgaps (PhBG) in these structures. They are designed so that the PhBG occurs in a given frequency range. Knowledge of the impact of deployment of the layets in the structure allows better design of these filters. The analysis was carried out using the transmission matrix method (TMM) algorithm. The transmission structures was examined for all permutations of a system of three layers made of different materials. The structure consisted of mercury, epoxy, rubber and PNM-0.38PT. The materials are chosen so that their characteristics largely differ. The structure was surrounded by water. The tests were carried out for the frequency range up to 1 MHz. Cases with different thickness of layers were analyzed. The tests have shown that regardless of the layer thickness, only three types of transmission structures exist in the six permutations of the system. Systems in which the middle layer remained unchanged, while the outermost layers were changed, were characterized by the same transmission structure. Increasing the thickness of the layers increased the number of transmission bands. Transmission strongly depends on the environment.The absorption of the materials used was not taken into account in the work. Interesting results can be obtained by analyzing the permutation of more complex structures. Changing the order of layers in the filter without changing its characteristics may affect the reduction of production costs and easier design of structures with given properties. The article shows repeating phononic transmission structure for different types of layers alignment.

A Narrow Band Pass Filter Using Technology Surface Mount Technology on Radar Frequency Generators

2016 ◽  
Vol 3 (1) ◽  
pp. 136
Author(s):  
I Dewa Putu Hermida ◽  
Deni Permana Kurniadi ◽  
Iqbal Syamsu
Keyword(s):  
Stop Band ◽  
Band Width ◽  
Signal Frequency ◽  
Band Pass Filter ◽  
Frequency Range ◽  
Pass Filter ◽  
Fmcw Radar ◽  
Frequency Generator ◽  
Band Depth ◽  
Radar Frequency

A BPF using SMT components. A cut-off frequency on a filter under cooling below LPF which works at  freq 310 MHz, while the cut-off frequency below a filter under cooling HPF which works at freq 306 MHz, so that the width of the band This filter is a type of narrow bandwidth filter 4 MHz. An 7 poles filter order with the aim to increase the steepness of the filter is generated, using the elliptic filter family or causer. Stop band width (Fs) to filter under cooling below about 20% in the frequency range 372 MHz, with stop band depth (As) of about 55 dB, while the stop band width (Fs) to filter under cooling of about 20% in the frequency range 245 MHz, with stop band depth (As) of about 55 dB. This filter is designed to pass the signal frequency division results DRO with a CF of 9856 MHz. Using SMT components, this circuit becomes very small and compact and has a high Q. The results of the simulation are generated, then this filter can realized system FMCW radar frequency generator.

Green Materials for Sound Absorption

2017 ◽  
Vol 729 ◽  
pp. 63-67 ◽  
Author(s):  
Amelia Trematerra ◽  
Ilaria Lombardi
Keyword(s):  
Sound Absorption ◽  
Flow Resistance ◽  
Noise Pollution ◽  
Acoustic Measurements ◽  
Frequency Range ◽  
Synthetic Materials ◽  
Green Materials ◽  
Acoustic Comfort ◽  
Useful Life ◽  
Materials Used

Green materials are becoming a valid alternative to traditional synthetic materials. The green materials can be used in different fields of the building constructions. The green materials are sustainable, infact the at the end of its useful life they can be dispersed into the environment without damaging it. So the green material can be used in improving the acoustic comfort inside environment, as well as to mitigate noise pollution. In this paper are reported the acoustic measurements of the properties of green materials. The absorption coefficient of samples of the materials, were measured in the frequency range from 200 Hz to 2,000 Hz with an impedance tube (tube of ”Kundt”); the flow resistance was also measured. Furthermore the problems about the realization of sound-absorbing panels composed of green materials, used for the acoustic correction of classroom, were discussed.

Frequency dependent electric properties of homogeneous multi-phase lossy media in the ground-penetrating radar frequency range

2013 ◽  
Vol 97 ◽  
pp. 81-88 ◽  
Author(s):  
Claudio Patriarca ◽  
Fabio Tosti ◽  
Casper Velds ◽  
Andrea Benedetto ◽  
Sébastien Lambot ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Electric Properties ◽  
Frequency Range ◽  
Frequency Dependent ◽  
Lossy Media ◽  
Multi Phase ◽  
Ground Penetrating ◽  
Radar Frequency

scholarly journals Obudowy dźwiękochłonno-izolacyjne urządzeń ultradźwiękowych, ograniczające poziom hałasu przenikającego do środowiska. Wyniki badań własnych

2021 ◽  
Vol 600 (9) ◽  
pp. 22-28
Author(s):  
Witold Mikulski ◽  
Keyword(s):  
Health Risk ◽  
Frequency Range ◽  
Effective Measure ◽  
Close Proximity ◽  
Ultrasonic Devices ◽  
Materials Used ◽  
Technical Solutions ◽  
The Impact

The article discusses the technical solutions of sound-absorbing and sound-insulating enclosures for devices that are sources of ultrasonic noise (sound frequencies range of 10-40 kHz). Due to the high health risk of employees operating ultrasonic technological devices and the fact that they are in close proximity to these devices, it is necessary to use an effective measure to reduce this risk, i.e. sound-insulating enclosures. So far, however, the rules for the use of such casings and the sound-insulating and sound-absorbing properties of their materials (in this frequency range) have not been defined. The article presents the results of own research on the impact of the materials used to make enclosures, linings of casings and the presence of openings (hole) in casings on the level of noise emitted by ultrasonic devices that penetrates into the environment.

Magnetic Materials Used in the Magnetic Core Manufacture of Electrical Machines and Transformers

2018 ◽  
Vol 775 ◽  
pp. 184-190 ◽  
Author(s):  
Gheorghe Paltanea ◽  
Veronica Manescu Paltanea ◽  
Horia Gavrila ◽  
Doina Elena Gavrila
Keyword(s):  
Rolling Direction ◽  
Magnetic Core ◽  
Electrical Machines ◽  
Energy Losses ◽  
Frequency Range ◽  
Silicon Iron ◽  
Materials Used ◽  
Traveling Wire ◽  
Conventional Laser ◽  
Single Strip

Two types of silicon iron steels, M400-65A non-oriented and MOH grain-oriented alloys were characterized using an industrial Brockhaus Single Strip Tester at two peak magnetic polarizations of 500 mT and 1000 mT in the frequency range from 10 Hz to 100 Hz. The samples were cut parallel to the rolling direction trough different cutting technologies, which are the classical mechanical-, then the non-conventional laser-, water-jet-and traveling wire electro-erosion methods. The loss separation concept was applied and the total energy losses, determined experimentally, for each sample were decomposed into hysteresis, classical (Foucault) and excess (anomalous) energy losses. A detailed analysis of each type of losses as a function of the frequency was made and the influence of the cutting technology was analyzed.

scholarly journals Study of 3D-Printed Dielectric Barrier Windows for Microwave Applications

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2225
Author(s):  
Mikhail D. Proyavin ◽  
Dmitry I. Sobolev ◽  
Vladimir V. Parshin ◽  
Vladimir I. Belousov ◽  
Sergey V. Mishakin ◽  
...  
Keyword(s):  
3D Printing ◽  
Frequency Band ◽  
Frequency Range ◽  
3D Printed ◽  
Microwave Applications ◽  
Materials Used ◽  
Manufacturing Technologies ◽  
Styrene Butadiene ◽  
Power Microwave ◽  
Butadiene Styrene

3D printing technologies offer significant advantages over conventional manufacturing technologies for objects with complicated shapes. This technology provides the potential to easily manufacture barrier windows with a low reflection in a wide frequency band. Several 3D printing methods were examined for this purpose, and the dielectric properties of the various types of materials used for 3D printing were experimentally studied in the frequency range 26–190 GHz. These measurements show that the styrene-butadiene-styrene and polyamide plastics are suitable for broadband low-reflection windows for low-to-medium-power microwave applications. Two barrier windows with optimized surface shapes were printed and tested. Results demonstrate that the studied technique can fabricate windows with a reflection level below −18 dB in the frequency band up to 160 GHz. Studied windows can be used for spectroscopic tasks and other wideband microwave applications.

scholarly journals Electromagnetic Wave Absorbing Materials on Radar Frequency Range

2019 ◽  
Vol 28 (1) ◽  
pp. 1
Author(s):  
Yana Taryana ◽  
Azwar Manaf ◽  
Nanang Sudrajat ◽  
Yuyu Wahyu
Keyword(s):  
Electromagnetic Wave ◽  
Frequency Range ◽  
Absorbing Materials ◽  
Radar Frequency

scholarly journals Broadband Metal-Dielectric Waveguide Path with Low Losses in the EHF Range

2021 ◽  
Vol 8 (3) ◽  
pp. 89-98
Author(s):  
V. V. Krutskikh ◽  
◽  
A. Yu. Sizyakova ◽  
M. S. Minkara ◽  
A. R. Ibrahim ◽  
...  
Keyword(s):  
Dielectric Waveguide ◽  
Unit Length ◽  
Circular Cross Section ◽  
Dielectric Waveguides ◽  
Structural Elements ◽  
Frequency Range ◽  
Metal Shield ◽  
Metal Waveguide ◽  
Materials Used ◽  
Dielectric Filling

. The present paper is devoted to the design of a new shielded metal-dielectric waveguide with low losses (less than 0.5 dB/m) and wide bandwidth for the 90–100 GHz frequency range. Various types of waveguide structures were analyzed, such as metal waveguides, oversized metal waveguides, dielectric waveguides, dielectric waveguides with a metal shield and various designs of the dielectric filling element. Estimates of loss per unit length in them are obtained. The design of a waveguide containing an oversized round metal screen and a dielectric element consisting of a plate and a rod, located in the center of symmetry of the device, is proposed. The task of creating a transition from the investigated waveguide to a standard rectangular metal waveguide is considered. It is a horn transition from a circular cross-section to a rectangular one with a length of more than 25 wavelengths with a dielectric structure continuing the dielectric element of the waveguide path. As a result of the work, the ratios of the dimensions of the structural elements of the waveguide path and the materials used were obtained that satisfy the required losses.

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