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Conducting Surface (conducting + surface)
Selected AbstractsScattering and absorption of electromagnetic waves on a plane with hemispherical bossesMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2007Xiaoxiong Gu Abstract We apply multiple scattering equations to study the scattering of electromagnetic waves on a perfectly conducting plane surface with a random dense distribution of hemispherical bosses. We derive a multipole solution up to third order to analyze close range interactions between nearby bosses. Results show significant improvement of accuracy compared with the traditional dipole approximation solution. Absorption on a lossy embossed surface is obtained from the field solution for the perfectly conducting surface. The surface current and absorption enhancement factor are further computed numerically. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2681,2686, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22855 [source] Analysis and characterization of transponder antennae for radio frequency identification (RFID) systemsPACKAGING TECHNOLOGY AND SCIENCE, Issue 1 2006T. C. Chau Abstract An investigation into the use of various radio frequency identification (RFID) antenna designs was performed. Passive RFID tag antennae with a resonant frequency range of 902,928,MHz were tested for robustness and efficiency in the Packaging Science RFID Laboratory at the University of Florida. Commercially available single- and dual-dipole tags were examined for read performance. Electromagnetic modelling software was used to model the impedance matching and detuning effects of nearby conducting surfaces. s-Parameters, current densities and polar plots of various dipole designs were estimated. Strategies used to shorten antenna length, such as capacitive loading, were evaluated. A simple half-wave dipole antenna was modelled in order to determine the effect of length on resonant frequency and performance. Parameter sweeps showed that a length of 14.4,cm was required for resonance at 915,MHz and 50,, termination. Capacitive loads shortened the dipole to 8.4,cm while adding 4.2,cm to height. It was verified that a conducting surface, such as metal packaging, had strong detuning effects on RFID tag antennae. Different methods, such as tuning stubs, alleviated the detuning effects by allowing bandwidths twice as large as with a simple dipole. Finally, the rationale for commercially available RFID antenna designs was discussed. It was found that analysis of actual antenna tag structures in the laboratory and exploring different methods to improve efficiency can lead to improvements in RFID performance. Copyright © 2005 John Wiley & Sons, Ltd. [source] Dynamics of end grafted DNA molecules and possible biosensor applicationsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 14 2006C. Sendner Abstract Polymers that are terminally attached to solid supports, so called brushes, form the basis for a wide variety of different applications in colloidal and biophysical sciences. For grafted charged chains a conducting surface allows to manipulate the brush structure by applying electric fields across the brush. The dynamics of oligomeric DNA molecules under the action of repulsive and attractive surface electric fields is studied by Brownian dynamics simulations including hydrodynamic effects and compared to experimental results. The difference in flexibility between double and single stranded DNA molecules leads to a change in the switching dynamics when repeatedly reversing the surface charge. This effect allows to detect hybridization of surface anchored DNA. Similar kinetic changes occur when other molecules bind terminally to DNA, opening the possibility to use end grafted polymers for general biosensing applications. We in particular discuss the influence of the adsorbate size and change on the switching dynamics. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Near Field Emission SEMIMAGING & MICROSCOPY (ELECTRONIC), Issue 1 2009Localised Electron Excitation Imaging via SPM Recent developments in electron optics enable "extreme" high-resolution Scanning Electron Microscopes (SEM)s to attain subnanometer resolution using landing energies as low as 200 eV, which is essential to prevent damaging of the investigated object and minimise the interaction volume. We have also implemented low beam energies in a simplified SEM where the electron source, remote in standard SEMs, is brought within tens of nanometers to the object. This microscope, which we call the "near field emission scanning electron microscope" (NFESEM), is capable of imaging conducting surfaces with nanometer resolution using beam energies less than 60eV. [source] Time-domain integral-equation based analysis of scattering from conducting surfaces including the singular edge behaviorMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2002Yongxue Yu Abstract A method for modeling singular electric currents near conducting edges within marching-on-in-time (MOT) simulators is presented. The use of singular basis functions in MOT simulators presents unique challenges not encountered in frequency-domain implementations. Numerical results demonstrate that the proposed expansion results in accelerated convergence for scatterers with sharp features. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 327,332, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10452 [source] Analysis and characterization of transponder antennae for radio frequency identification (RFID) systemsPACKAGING TECHNOLOGY AND SCIENCE, Issue 1 2006T. C. Chau Abstract An investigation into the use of various radio frequency identification (RFID) antenna designs was performed. Passive RFID tag antennae with a resonant frequency range of 902,928,MHz were tested for robustness and efficiency in the Packaging Science RFID Laboratory at the University of Florida. Commercially available single- and dual-dipole tags were examined for read performance. Electromagnetic modelling software was used to model the impedance matching and detuning effects of nearby conducting surfaces. s-Parameters, current densities and polar plots of various dipole designs were estimated. Strategies used to shorten antenna length, such as capacitive loading, were evaluated. A simple half-wave dipole antenna was modelled in order to determine the effect of length on resonant frequency and performance. Parameter sweeps showed that a length of 14.4,cm was required for resonance at 915,MHz and 50,, termination. Capacitive loads shortened the dipole to 8.4,cm while adding 4.2,cm to height. It was verified that a conducting surface, such as metal packaging, had strong detuning effects on RFID tag antennae. Different methods, such as tuning stubs, alleviated the detuning effects by allowing bandwidths twice as large as with a simple dipole. Finally, the rationale for commercially available RFID antenna designs was discussed. It was found that analysis of actual antenna tag structures in the laboratory and exploring different methods to improve efficiency can lead to improvements in RFID performance. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||