Frequency-selective surfaces (FSSs) on thin substrates using screen printing technology are popular due to their flexible nature, low profile, easy installation, and low-cost mass production. This paper proposes the deployment of printed FSS window panes in office buildings investigates shielding effect radio wave propagation through such structures. The surface is an array modified meandered squares with a unit cell size <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML"...

In this paper, the anisotropic conductivity effect of quasiisotropic carbon fiber laminates on conformal load-bearing antenna structures (CLAS) is presented.The a quasi-isotropic IM7/977-3 CFRP laminate measured using waveguide techniques.The results show that orientation surface ply relative to polarization incident E-field has major influence reflectivity.This difference attributed fact fibres oriented parallel plies behave as good conductors, while off-axis present lossy dielectric layers...

Design of a rectangular spiral planar inverted-F antenna (PIFA) at 915 MHz for wireless power transmission applications is proposed. The and rectifying circuitry form rectenna, which can produce dc from distant radio frequency energy transmitter. generated used to operate low-power deep brain stimulation pulse generator. proposed has the dimensions 10 mm × 12.5 1.5 resonance with measured bandwidth 15 return loss -10 dB. A dielectric substrate FR-4 ε <sub...

Radio frequency identification (RFID) antenna efficiency is an important component of link budget design. A method moments technique based on the summation segment currents compares favorably with two different results obtained using finite element (radiation pattern integration and Wheeler cap). The a resonant dipole was found to be proportional inverse square root conductivity. For typical RFID meander line in free space relationship more severe

In this article, the feasibility of using a circular microstrip patch antenna to measure strain and effects different materials on sensitivity are investigated. Also, effect direction frequency shift is studied. The theoretical model shows linear relationship between in resonant any material. Both finite element analysis (FEA) experimental tests have been undertaken corroborate shift. addition, new sensor based meandered antennas has designed tested overcome shortcomings patch. exhibited...

A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It designed, fabricated and tested in the range 10-20 GHz. The plane wave transmission reflection coefficients agreed with numerical modelling. effective thickness of backing sheet has a significant effect characteristics. stop band reduced from 15GHz (no backing) to 12.5GHz polycarbonate. beyond 1.8mm minimal resonant frequency....

Recently introduced passive wireless strain sensors based on microstrip patch antennas have shown great potential for reliable health and usage monitoring in aerospace civil industries. However, the interrogation range of these is limited to few centimeters, which restricts their practical application. This paper presents an investigation effect circular antenna (CMPA) design quality factor maximum reading sensor. The results reveal that by using appropriate substrate materials distance CMPA...

Linearly polarized rectangular patch antennas printed on light-weight cotton clothing are subject to both convex and concave bending. Changes in resonant frequency resulting from H plane bending explained terms of changes effective length. Agreement between theory, practical simulation results was observed. The changed by up 8% for extreme although the bandwidth remains essentially unchanged at 4.5%. A 16.8% achieved using a double U-Slotted which minimized problem.

Radio Frequency IDentification (RFID) technology is increasingly being used to uniquely identify objects. An important component of RFID systems the design antenna - which usually takes form a compacted meander line. This task becomes an optimisation problem as different designs will have efficiencies and resonant frequencies. In this paper, we explore use multi-objective version ant colony system. constructive meta-heuristic, shown, highly suitable for problem.

Fixed area meander line antennas designed on a 5 × rectangular grid were optimized for efficiency and resonant frequency. The Pareto front was developed using ant colony optimization the numerical electromagnetic code. lowest frequency antenna fits an of 0.11λ0 0.05λ0 with 88%. © 2009 Wiley Periodicals, Inc. Int J RF Microwave CAE, 2009.

Carbon fibers are finite conductors with a weak diamagnetic response in static magnetic field. When illuminated high-frequency alternating electromagnetic wave such that the skin depth is greater than fiber diameter, carbon-fiber composites shown to exhibit strong dynamic response. The susceptibility (χm) controlled by polarization angle (θ), which between incident electric field and conductor direction. A closed form solution for this behaviour was derived using Maxwell's equations an...

Aircraft skins manufactured from carbon fibre reinforced plastic (CFRP) can simultaneously support structural load and act as antennas. This offers the potential for disproportionately large antenna elements arrays, thus enhanced aircraft capability. The efficient design of such structures requires that link between CFRP microstructure electromagnetic performance be established. paper presents a method predicting attenuation waveguides CFRP. considers both orthotropic, complex conductivity...

Conformal load-bearing antenna structures, which afford structures with radar capability, are a promising technology to reduce weight and drag of air vehicles. This article presents an investigation the mechanical electromagnetic performance slot log-spiral in carbon-fibre composite structures. Compared traditional rectangular slots, equiangular spiral is found offer broader bandwidth better strength. Through experimental testing finite element analyses, new tip design proposed that can...

The relation between loss resistance and conductivity for monopole antennas over a ground plane is derived. Its accuracy was confirmed by good agreement it finite element method of moments simulations. This may be used to calculate any material that radiates. A Wheeler Cap system setup. System losses were determined equating the 70 mm long × 1.17 diameter copper at resonance with predicted using published this material. 2 wide thick antenna manufactured from an aerospace grade carbon fibre...

Not all meander line dipole antennas (MLDAs) plotted on the same grid necessarily have similar characteristics. MLDAs can be optimized for best efficiency, lowest resonant frequency or highest impedance. Different structures were investigated using a 5 times 10 array of rectangular points in 4times9 mm2 area and, symmetrical MLDA that incorporate grids modeled to determine and efficiency. Based NEC simulation results possible family members, range frequencies was 3.51 4.71 GHz efficiencies...

Increasing the efficiency of meander line antennas is an important real-world problem within radio frequency identification (RFID). Meta-heuristic search algorithms, such as ant colony optimisation, are very efficient at solving problems that require paths to be constructed. This technique adapted solve grid based path for and incorporates NEC evaluation suite. The results sizes up 10 times indicates optimisation extremely effective this problem.

A new form of a conformal load-bearing antenna structure that consists cavity-backed slot in carbon-fiber reinforced polymer (CFRP) panel is presented. The fed via coaxial cable and patches capacitively couple energy into the highly conductive carbon fibers without requirement to abrade off nonconductive epoxy resin layer on surface. Computational simulations, which are validated by experiments, show this feed configuration as effective soldering brass antenna. Backing with CFRP cavity...

The efficient design of meander line antennas for RFID devices is a significant real-world problem. Traditional manual tuning antenna designs becoming impractical larger problems. Thus the use automated techniques, in form combinatorial search algorithms, necessity. Ant colony system (ACS) very meta-heuristic that commonly used to solve path construction Apart from its own native capacity, ACS can be dramatically improved by combining it with local strategies. As shown this paper, applying...

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Based on 2D meander line methods, <formula formulatype="inline"><tex Notation="TeX">$3\times 3\times 3$</tex></formula> point, symmetrical, 3D dipole antennas structure was investigated exhaustively to identify those configurations with the highest efficiency and lowest resonant frequency for a fixed length. Maximum input impedance occurs when adjacent high current segments in antenna are...

A low profile, thin, flexible dual layer frequency selective surface (FSS) operating in L-band has been designed and fabricated using screen printing technology. The composite FSS structure was achieved by meandering the basic λ o/22 square loop at its four corners filling space on top half period offset pattern bottom, which produces a reject band 1.89 GHz. response of for both transverse electric magnetic polarisations various angles incidence measured simulated results single as well...