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Analogies with physical phenomena indicate that modulation of a material or geometrical parameter of a periodic structure enriches its original band structure. The present work aims to provide an insight into the band-splitting phenomenon in the case of commensurate modulation for a parallel-plate waveguide technology-based geometry. A modulated one-dimensional parallel-plate waveguide signal integrity...
In this paper, measurements of the spectral occupancy in some high frequency (HF) bands in the Western part of Romania are presented. Signals have been acquisitioned by means of an Universal Software Radio Peripheral (USRP) equipment and spectrum occupancy values have been calculated off-line for a set of frequency bands that present interest for establishing of a system for emergency communications...
The Radiated emission measurement is one of the tests required in EMC testing. CISPR 25 standard specifies the frequency range and the antennas used for this purpose. In this paper, differences that appear when using different measurement antennas and different semi-anechoic chambers in radiated emissions testing on the same DUT are investigated. Results show sometimes significant differences that...
Results concerning joint Spectrum Availability (SA) monitoring in the 5–10 MHz range of the High Frequency (HF) band (3–30 MHz), for a 24-hour period, in two locations situated in the central and western part of Romania are reported. Measurements have been realized simultaneously in the two locations, with similar USRP SDR-based equipment, for 24 hours on February 27, 2017. Results indicate that SO...
The radiated immunity measurement is one of the tests that covers electromagnetic compatibility testing. The purpose of the paper is to investigate the performance of an automotive DUT test in the presence of an electromagnetic field inside a semi-anechoic chamber. The test complies with the ISO 11452-2 Standard.
Radiated immunity testing in the automotive industry is an activity with ever increasing importance. Immunity tests are being performed in the semi-anechoic chamber of the EMC laboratory, within Continental Automotive Romania. Testing results rely on measurements performed by operators and nominal parameters of the equipment involved, which are input to the testing software. In this paper, we show...
The ionospheric channel is time-variant and is affected by several factors such as variable attenuation, fading, modification of the polarization plane of waves, Doppler shift and nonlinearities. Therefore, communication channels through the ionosphere are subject to a high degree of variability. Nevertheless, communication through the ionospheric channel presents interest due to the modest requirements...
The radiated emissions measurement is one of the tests involved in Electromagnetic Compatibility testing. In this paper a measurement setup for radiated emissions from an automotive cluster is proposed. Assessment of correct operation of a device under test (DUT) according to the CISPR25 standard is reported. The test setup is based on measured data on different antennas that were performed in order...
We propose a technique to build artificial anisotropic dielectrics by using periodic insertions of a homogeneous material in a homogeneous substrate, characterized by a different dielectric constant. We calculate the effective dielectric constants corresponding to the three principal directions by means of dispersion diagrams associated to the periodic structure. The proposed method to realize low...
A 2D, volumetric (i.e., non-planar), structure consisting of two dielectric layers, loaded by various metal inclusions on multiple-periodic grids and closed by two confining metal planes is introduced in view of advanced dispersion engineering related applications. Full-wave simulation has been used to demonstrate that, for axial propagation, the structure presents (i) a large electromagnetic band-gap...
The dispersion diagram of a 2D periodic structure built in stripline technology is determined by full-wave simulation. One of the geometrical parameter of the structure is then binary modulated in two orthogonal directions, yielding a new periodic structure with a unit cell that is four times larger with respect to the original one. The calculated dispersion diagram of the latter structure exhibits...
In this paper a simple methodology to retrieve the effective refractive index of a heterogeneous dielectric substrate is proposed. The host dielectric material is filled with small spherical dielectric inclusions which are arranged in a cubic lattice to form a heterogeneous dielectric. The proposed technique relies on the determination of the dispersion diagram (DD) of a unit cell that consists of...
Metamaterials that present electromagnetic band-gaps have found many applications in solving signal integrity issues. In particular, inserting a metamaterial in a metal screening box prevents launching of cavity modes within the frequency range of the electromagnetic band-gap(s) and avoids in this way the necessity of insertion of resistive layers. We propose a solution for building a metal screening...
Thermal applications of Solar Energy have gained attention in the last decades due to economical and ecological reasons. In order to be competitive with respect to fossil fuel-based power systems, investment and O&M costs have to drop. We propose an economic assessment of two thermal solar systems designed for operation in the western part of Romania. We show that deployment of a large number...
Application of 2D structures that present electromagnetic band-gaps (EBG's) to signal integrity issues has been a subject of interest in the last decade. An important problem to be solved is to match the EBG and the spectrum of the noise. This can be done, among others, by using materials with prescribed dielectric constants which is usually of high value and consequently a costly solution. A cheaper...
PV power systems have gained much attention in the last decades due to the clean operation and potential benefits in fossil fuel and greenhouse gas sparings. An economic analysis of grid-connected, small-scale, residential PV systems is proposed, based on the levelized cost of energy is proposed. Economy in gas emission is also estimated. All calculations rely on measured radiation and energy production...
We present an economic assessment of three solar thermal applications developed at the “Politehnica” University of Timişoara, Romania. The technical and solar radiation data have been obtained by measurements performed in the solar energy laboratories of the university. The economic effectiveness of the solar systems is assessed in terms of the present worth of the cash flow calculated for the life...
The problem of intermodulation distortions introduced by ferromagnetic materials inclusions in the construction of equipment used for transmission and processing of GSM signals is addressed. A Rayleigh model is implemented for determination of the response of ferromagnetic materials to two-tone signals. Results of experiments performed on coaxial transmission lines built with ferromagnetic materials...
We consider a periodic structure that consists of on a 3D geometry periodically repeated in a plane embedded between two dielectric layers covered with metal planes. The geometry consists of a circular metal patch connected to the ground plane by four metal vias. Additionally to these reactive loads, a volumetric corrugation is further considered, that will be responsible for the shift toward low...
We propose a framework for calculation of the energy balance of an outdoor swimming pool intended for potential users of solar energy in the region of Timisoara, Romania. The algorithm is based on physical and practical considerations, on existing experience in the field and on measurements of solar radiation. According to the calculations, a solar swimming pool with an area of 160 m2 has energy losses...
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