Prof. Razvan D. Tamas
Department of Electronics and Telecommunications, Constanta Maritime University, Constanţa, Romania
+1
'%3e%3cpath%20d='M22.1642%2019.0924C21.7317%2018.068%2021.1041%2017.1375%2020.3163%2016.3527C19.5309%2015.5656%2018.6006%2014.9381%2017.5766%2014.5048C17.5674%2014.5002%2017.5582%2014.4979%2017.5491%2014.4933C18.9774%2013.4616%2019.9059%2011.7811%2019.9059%209.88504C19.9059%206.74408%2017.3611%204.19922%2014.2201%204.19922C11.0792%204.19922%208.53429%206.74408%208.53429%209.88504C8.53429%2011.7811%209.46282%2013.4616%2010.8912%2014.4956C10.882%2014.5002%2010.8728%2014.5025%2010.8636%2014.5071C9.83652%2014.9404%208.91487%2015.5617%208.1239%2016.355C7.33685%2017.1404%206.70933%2018.0707%206.276%2019.0947C5.85031%2020.0972%205.62072%2021.172%205.59967%2022.2609C5.59905%2022.2853%205.60335%2022.3097%205.61229%2022.3325C5.62123%2022.3553%205.63465%2022.376%205.65174%2022.3935C5.66883%2022.4111%205.68926%2022.425%205.71182%2022.4345C5.73437%2022.444%205.7586%2022.4489%205.78308%2022.4489H7.15868C7.25956%2022.4489%207.3398%2022.3686%207.3421%2022.2701C7.38795%2020.5001%208.09868%2018.8425%209.35506%2017.5861C10.655%2016.2862%2012.3814%2015.5709%2014.2201%2015.5709C16.0588%2015.5709%2017.7852%2016.2862%2019.0852%2017.5861C20.3415%2018.8425%2021.0523%2020.5001%2021.0981%2022.2701C21.1004%2022.3709%2021.1807%2022.4489%2021.2815%2022.4489H22.6571C22.6816%2022.4489%2022.7058%2022.444%2022.7284%2022.4345C22.751%2022.425%2022.7714%2022.4111%2022.7885%2022.3935C22.8056%2022.376%2022.819%2022.3553%2022.8279%2022.3325C22.8369%2022.3097%2022.8412%2022.2853%2022.8406%2022.2609C22.8176%2021.165%2022.5907%2020.0989%2022.1642%2019.0924ZM14.2201%2013.8284C13.1678%2013.8284%2012.1773%2013.418%2011.4322%2012.6729C10.6871%2011.9278%2010.2767%2010.9374%2010.2767%209.88504C10.2767%208.83271%2010.6871%207.84227%2011.4322%207.09715C12.1773%206.35204%2013.1678%205.94165%2014.2201%205.94165C15.2724%205.94165%2016.2629%206.35204%2017.008%207.09715C17.7531%207.84227%2018.1635%208.83271%2018.1635%209.88504C18.1635%2010.9374%2017.7531%2011.9278%2017.008%2012.6729C16.2629%2013.418%2015.2724%2013.8284%2014.2201%2013.8284Z'%20fill='%238590A2'/%3e%3c/g%3e%3c/svg%3e)
Co-authors
Following
Followers
Research Focus & Metrics
Explore full metrics on Scilit
Academic Career Length
22Years (2005-Present)
(Calculated once Scilit publication data is synced: current year − year of first publication + 1)
Representative Publications
View All Publications23 April 2014 in Microwave and Optical Technology Letters
Journal Article
Razvan D. TamasDDDaniela Deacu
Daniela Deacu
Gabriel VASILECICornel Ioana
Cornel Ioana
18 April 2016 in Applied Physics Letters
Journal Article
LPL. Pometcu
L. PometcuASAla Sharaiha
Ala SharaihaRBR. Benzerga
R. Benzerga
Razvan D. TamasPPP. Pouliguen
P. Pouliguen
This paper presents a characterization method for extracting the reflection coefficient of materials and the real part of their permittivity. The characterization is performed in a real environment, as opposed to the classical measurement methods that require an anechoic chamber. In order to reduce the effects of the multipath propagation, a free space bistatic measurement was performed at different distances material-antennas in far field. By using a Teflon sample and a commercial absorbing material sample, measurements have been performed in order to validate the characterization technique.
1 May 2014
Conference Paper
Angela DigulescuMPMirel Paun
Mirel Paun
CVCostin Vasile
Costin Vasile
TPTeodor Petrut
Teodor PetrutDDDaniela Deacu
Daniela Deacu
Razvan D. Tamas +1
This paper presents two methods applied in the context of surveilling and localizing electrical arcs which usually occur in photovoltaic power systems. The wavelet analysis has proved to be very powerful in transient signal detection, namely in multiscale edge detection, thereby we use this method to detect the electrical arcs and to localize them in time. Secondly, we applied the recurrence plot analysis (RPA) which presented succesful results in partial discharge time localization. In order to obtain the space localization of the electrical arc, we used the time-of-arrival of the arc at the acoustic sensor system. The system is composed of four sensors and the space localization is based on time difference of arrival, resulted from the time detection based on wavelet analysis and on RPA method.
Journal Article
Andreea Constantin (Platica)Razvan D. TamasCommon mode currents on antenna feeders usually occur when feeding a symmetric radiator through an asymmetric line, or when the ground plane is electrically small. Such currents may have magnitudes comparable to the feed currents and therefore have a major impact on the total radiated field. For antenna radiation measurements, both assessment and reduction of the common mode currents on antenna feeders are crucial. Techniques to discriminate antenna and feeder radiation are mainly needed for design and optimization purposes. Antenna gain measurements in a multipath site can be performed by using the distance averaging method. In this paper, we show that the distance averaging technique can be applied to reduce the effect of common mode currents for measuring the field radiated by symmetrical antennas. Two measuring configurations are proposed depending on the number of symmetry degrees of the antenna under test, and a differential approach for extracting the field created by the common mode currents was also developed. The experimental validation was performed by measuring a simple wire dipole and a log-periodic dipole array (LPDA) with a small square loop as a probe, both on the feeder side and on the feeder free side.
1 January 2017
Conference Paper
LALiliana Anchidin
Liliana Anchidin
Razvan D. TamasAAAdrian Androne
Adrian Androne
GCGeorge Caruntu
George Caruntu
Antenna gain is generally extracted from near-field measurements when the size of the measuring site (anechoic chamber or open area test site) does not meet the far-field constraints that include both distance and probe size limitation. Near-field measurements are usually performed by scanning the field on a closed surface around the antenna with a small size probe. In this paper, we show that the distance averaging method that we have previously proposed for gain evaluation in a multipath environment can also be employed for measurements in the near-field zone. We introduce an alternative technique to extract the gain by applying weighting functions on the near-field data when the size of the probe cannot be neglected compared to the wavelength. We validated our method by comparing the results to the gain measured at distances in the far-field region.
15 April 2019 in IEEE Antennas and Wireless Propagation Letters
Journal Article
This letter presents a novel inverse scattering method for estimating the radar cross section of a target placed in the Fresnel region of the radar antennas. By considering a constant current distribution on the transmitting antenna and a uniform illumination of the target and furthermore of the receiving antenna, the electromagnetic field is averaged over the apertures of the antennas. The hypothesis of a constant current distribution stands for ultra-wide band antennas, and a quasi-uniform illumination can be assumed for ranges within the Fresnel region and for the particular case where antenna and target sizes are in the same order as the distance to the target. A calibration procedure for the measurement setup is also proposed. A validation of the method through simulations and measurements in an anechoic chamber and in a real, multipath propagation environment is provided by using two different types of antenna systems.
About Me
Razvan D. Tamas received the Ph.D. degree jointly from University Politehnica of Bucharest, Romania, and from Institut Polytechnique de Grenoble, France, and the Habilitation degree (Habilitation à Diriger des Recherches) from Institut Polytechnique de Grenoble, France. He is currently a Professor, head of the Electronics and Telecommunications Department at Constanta Maritime University, Romania, and a Ph.D. supervisor with the Doctoral School of Electronics and Telecommunications at the National University of Science and Technology “Politehnica” of Bucharest, Romania. He was formerly a Senior Researcher with the Navy Scientific Research Center of the Military Equipment and Technology Research Agency, Romania. His field of interest includes antenna measurements, numerical methods for electromagnetism, time-domain characterization, electromagnetic compatibility, and naval communication systems. Razvan D. Tamas is a Senior Member of the IEEE. He founded the IEEE AP-S/CRFID Joint Chapter in Romania, and he served as a Chair between 2017 and 2022; he is presently the Honorary Chapter Chair. He also serves as a Vice-Chair of the IEEE GRSS Chapter in Romania, and as a Technical Activities Chair at the IEEE Romania Section. In 2023, Prof. Tamas founded the Romanian Association on Antennas and Propagation. He is also the Romanian representative at the URSI – Commission A, Working Group A1: Education and training for Electromagnetic Metrology.