A solution for mitigation of parallel‐plate noise in power distribution networks of high speed digital and mixed‐signal circuits and of printed circuit boards based on an inhomogeneous parallel‐plate waveguide (PPW) is proposed. The PPW consists of two different dielectric layers and a high impedance surface at their interface. The frequency related properties of the structure are studied through the numerically computed dispersion diagram. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1689–1692, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26918

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A frequency selective surface for spatial filtering in the standardized Ultra-Wide Band (UWB) frequency range is proposed. A very large stop-band of 1.75–15.44 GHz has been obtained, with good polarization insensitivity and an angular stability of more than 60∘ and more than 50∘ in TE and TM incidence, respectively. Circuit models have been devised. The structure has been assessed by electromagnetic simulation and implemented on an FR4 substrate of 1.6 mm thickness, with an edge of the square-shaped unit cell of 15 mm. Tests in an anechoic chamber demonstrated good matching between simulation and experimental results and proper operation of the device.

We study the Doppler shift in the frequency of an acoustic or light wave emitted by a source at rest with respect to an inertial reference frame and received by an accelerated observer, and the same problem for a light wave emitted by an accelerated source and received by an inertial observer. The non-locality in the frequency measurement by an accelerating observer is taken into account, noting that two successive zeros of the wave are received at two different points in space, where the velocities of the receiver or source are different.

The photovoltaic system within the "Politehnica" of University of Timişoara, Romania has a surface of the PV cells of 16.06 m 2 and a total surface of the panels of 18.30 m 2 . In the period April 2011 -February 2012 it worked with an average efficiency of 12.66% and with an annual energy efficiency of 1267.5 kWh/kW p . The installations injects electrical energy in the public grid. The PV system is used for educational practical applications for Master degree students in Solar Energy, for realization of dissertation theses and for public dissemination of information on solar energy. An assessment of the performances of the system based on measured data is provided in this communication. The results are useful for solar energy users interested in installing PV systems in the region.