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By reducing the coating thickness of the weak scattering source, the coating weight of the absorbing material can be reduced by 35% with little effect on the RCS.

To alleviate the weight-increasing problem caused by a large number of coating of absorbing materials, a method for zonal coating of absorbing materials for a stealth helicopter was proposed. By appropriately reducing the thickness of the coating at the secondary scattering locations, the amount of coating used is significantly reduced.

Compared with the full-coated, the zonal coating scheme achieves the corresponding RCS reduction effect.

Zonal coating design can achieve the effect of reducing coating weight and cost.

The effects of different coating methods on RCS were verified by electromagnetic scattering simulation, and the applicability of the zonal coating design of the absorbing material to the stealth helicopter was verified.

The purpose of this paper is to investigate cotton fabric behavior that is exposed to radar waves between selected operation frequencies as an alternative radar-absorbing material (RAM) response. Cotton fabric biocomposite materials were compared with carbon fabric composite materials, which are good absorbers, in terms of mechanical and electromagnetic (EM) properties for that purpose.

The laminated composite plates were manufactured by using a vacuum infusion process. The EM tests were experimentally performed with a vector network analyzer to measure reflection, transmission and absorption ability of cotton fabric, carbon fabric and cotton–carbon fabric (side by side) composite plates between 3 and 18 GHz. The tensile and low-velocity impact tests were carried out to compare the mechanical properties of cotton fabric and carbon fabric composite plates. A scanning electron microscope was used for viewing the topographical features of fracture surfaces.

The cotton fabric composite plate exhibits low mechanical values, but it gives higher EM wave absorption values than the carbon fabric composite plate in certain frequency ranges. Comparing the EM absorption properties of the combination of cotton and carbon composites with those of the carbon composite alone, it appears that the cotton–carbon combination can be considered as a better absorber than the carbon composite in a frequency range from 12 to 18 GHz at Ku band.

This paper shows how cotton, which is a natural and easily supplied low-cost raw material, can be evaluated as a RAM.

Research workers in the U.S. are developing new radar absorbing materials that can be sprayed on transparent surfaces such as cockpit canopies and sensor ports to blunt detection of older aircraft and precision‐guided wea‐pons.Older aircraft have large radar cross sections, and externally mounted weapons and sensor packages increasing their vulnerability.The reflection of car lights from an animal's eyes is an effect similar to radar's reflection from the transparent section of a forward‐looking infrared sensor or television camera. The effect is known as retro‐reflection to reduce these radar returns, researchers are working on a variety of optically transparent, radar absorbing materials that if properly applied to cockpit canopies, Lantirn pods, and SLAM or Maverick missile heads will make them almost invisible to radar.

As a good absorbing material candidate, a functionally graded wave absorber can be tailored to satisfy the impedance match principle by gradually changing material property. The paper aims to discuss these issues.

The electromagnetic wave absorption properties are discussed. An analysis model is proposed to provide an insight into its mechanical characteristics during wave absorption. Considering the energy-converting and thermal deformation properties, the thermoelastic behaviors of an absorber are analyzed by numerical method. The effects of material and geometrical properties are discussed in detail.

The results demonstrate that absorbing effect of graded composite is enhanced. Good performance of low reflectance and high absorption with gentle thermal stress distribution can be obtained by proper designing of the gradient absorber.

Functionally graded materials exhibit a progressive compositional gradient change along certain dimension of structures, which can be used as absorbing materials for the gradual change of material property tailored to satisfy the principle of impedance match. The design of functionally graded absorbing materials usually should consider not only the electromagnetic performance, but also the mechanical properties simultaneously. Therefore, few investigations have addressed the mechanical characteristics of absorbers. This paper presents some studies on the electromagnetic, especially mechanical behaviors during electromagnetic wave absorption. It is helpful to provide mechanical reference for designing an absorber.

A design procedure for multi-layer absorbers based on carbon nanotubes (CNT) frequency selective surfaces (FSS) sheets is here developed. The paper aims to discuss there issues.

Single layer FSS are first analyzed via finite element (FE). Then equivalent sheets admittances are extracted in a transmission line model. Neural networks (NNs) interpolation over this data and subsequent multi-objective genetic algorithm (GA) based optimizations are then performed to design multiple layers absorbing structures. Designs are finally validated via full wave FEM simulations.

In this paper, some absorbing structures made of three or four FSS sheets with total thicknesses around 6 mm are synthesized.

NNs' accuracy used in the equivalent model can be refined with further training.

Low profile absorbing materials are of relevant industrial interest both for radar cloaking and anechoic chambers.

The transmission line model combined with NNs and GA optimization is capable of speeding up the design procedure with respect to a conventional full-wave FEM approach.

Examines the fourteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

The purpose of the present work is to fabricate composite with strong absorbing nature and with more strength. The usage of wireless communication is increasing day by day, electromagnetic absorbing material is required to reduce this pollution. In the present experimental investigation, composites were fabricated for zero and 45° fiber orientation and as a filler material of Multiwall Carbon Nanotubes (MWCNTs) for the proposed percentage in the composites. Microwave absorbing properties were investigated for both perfect electric conductor (PEC)-backed composites and without PEC-backed composites.

The electromagnetic absorbing performance was analyzed based on complex permeability, complex permittivity, dielectric tangent and magnetic tangent losses. The experimentation was done by Vector Network Analyzer in the frequency range of 8.2 to 12.4 GHz by X-band. The surface morphological study was done. The mechanical and thermal properties are also investigated for these composites.

By investigating the experimental values, the induced percentage of MWCNTs and PEC of composites affects the electromagnetic and microwave absorption properties of the composites. The microwave absorption properties improved when the composites were able to absorb wide bandwidth and low reflection loss. The best results are obtained for PEC-backed composites for 5%, which is about −43.56 dB at 11.1 GHz compared to without PEC-backed composites. The reflection loss is developed by the dielectric loss initiated from MWCNTs and by PEC.

To the best of the authors’ knowledge, no work was reported on hand lay-up method and PEC-backed composites in electromagnetic absorption properties with regression analysis.

The aim of this study is to determine the fracture behavior of wool felt and fabric based epoxy composites and their responses to electromagnetic waves.

Notched and unnotched tensile tests of composites made of wool only and hybridized with a glass fiber layer were carried out, and fracture behavior and toughness at macro scale were determined. They were exposed to electromagnetic waves between 8 and 18 GHz frequencies using two horn antennas.

The keratin and lignin layer on the surface of the wool felt caused lower values to be obtained compared to the mechanical values given by pure epoxy. However, the use of wool felt in the symmetry layer of the laminated composite material provided higher mechanical values than the composite with glass fiber in the symmetry layer due to the mechanical interlocking it created. The use of wool in fabric form resulted in an increase in the modulus of elasticity, but no change in fracture toughness was observed. As a result of the electromagnetic analysis, it was also seen in the electromagnetic analysis that the transmittance of the materials was high, and the reflectance was low throughout the applied frequency range. Hence, it was concluded that all of the manufactured materials could be used as radome material over a wide band.

Sheep wool is an easy-to-supply and low-cost material. In this paper, it is presented that sheep wool can be evaluated as a biocomposite material and used for radome applications.

The combined evaluation of felt and fabric forms of a natural and inexpensive reinforcing element such as sheep wool and the combined evaluation of fracture mechanics and electromagnetic absorption properties will contribute to the evaluation of biocomposites in aviation.

The purpose of this paper is to investigate the effect of doping element on the microwave absorption performance of hexagonal nano boron nitride (h-nBN)-reinforced basalt fabric (BF)/epoxy composites. A new type of hybrid composite that will be produced by the use of boron nitride as an additive that leads to increased radar absorption capability will be developed and a new material that can be used in aeronautical radar applications.

This study is focused on the microwave absorption properties of h-nBN doped basalt fabric-reinforced epoxy composites. Basalt fabric (BF)/epoxy composites (pure composites) and the BF/h-nBN (1 Wt.% h-nBN doped composites) hybrid composites were fabricated by vacuum infusion method. Phase identification of the composites were performed using X-ray diffraction (XRD), the 2θ scan range was from 10 to 60 with the scanning speed of 3°/min and surface morphologies of the composites were investigated using scanning electron microscopy (SEM). Microwave properties of samples were investigated through transmission/reflection measurements in Agilent brand 2-Port PNA-L Network Analyzer in the frequency range of 3–18 GHz. The prepared sample is positioned between two horn antennas with and without metal plate.

Experimental results show that h-nBN doped composite was synthesized successfully and the produced hexagonal nano boron nitride-added fiber laminated composite material has good absorption behavior when they are used with metallic sheets and good for isolation applications at many points in the 3–18 GHz band.

This paper will contribute to the literature on the use of basalt fabric, which are new types of fibers, and hexagonal nano boron nitride and the effects of boron nitride on radar absorption properties of composite material. It presents detail characterization of each composite by using XRD and scanning electron microscopy.

The series 7458 small square‐case counter provides a compact, ½ oz counter with good figure legibility. Extensive use of precision moulded acetal resin in the construction ensures low torque and long life. Five types of drive are available — direct, revolution, ratchet, rotary ratchet and geared. They can be arranged for left or right hand shaft extension and four different mounting arrangements are available, flange, plain, panel or lug. According to drive, either 5, 6 or 7 figure models can be supplied. Normal speed is 1,000 cpm except for the direct drive model which has a speed of 5,000 cpm. Figures are white on black, 0·170 in. high by 0·087 in. wide.