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S. N. Yerin - One of the best experts on this subject based on the ideXlab platform.

  • Effect of the ground screen on sensitivity of low-frequency radio telescope Array Element
    2017 XI International Conference on Antenna Theory and Techniques (ICATT), 2017
    Co-Authors: Peter L. Tokarsky, Alexandr A. Konovalenko, S. N. Yerin
    Abstract:

    The Giant Ukrainian Radio Telescope (GURT) is a new generation radio telescope with active phased antenna Array intended to operate within 10–80 MHz range. The radio telescope is being constructed now in Ukraine. The Array Elements are active antennas in form of flat wire dipoles integrated with low-noise preamplifiers. In the paper we present a comparative analysis of two GURT Array Element versions that differ in presence or absence of wire grid ground screen under the dipole. The analysis results are given and discussed.

  • Sensitivity of an Active Antenna Array Element for the Low-Frequency Radio Telescope GURT
    IEEE Transactions on Antennas and Propagation, 2017
    Co-Authors: Peter L. Tokarsky, Alexandr A. Konovalenko, S. N. Yerin
    Abstract:

    The recently developed new generation, low-frequency Giant Ukrainian Radio Telescope (GURT) is built nearby the well-known Ukrainian T-shaped Radio Telescope. The new facility employs a phased antenna Array composed of many subArrays of $5 \times 5$ active antenna Elements. In this paper, the parameters of the active antenna used as Array Element are studied, with special attention paid to sensitivity. The electrical and noise parameters are calculated using computer simulation and wave techniques for noise modeling of two-port networks. The results of numerical calculations of the sensitivity are given in terms of the sky noise dominance (SND) and system equivalent flux density of the GURT Element within 10–80 MHz. The calculated results are compared with in situ measurements.

  • Sensitivity of Active Phased Antenna Array Element of Gurt Radio Telescope
    Radio physics and radio astronomy, 2016
    Co-Authors: Peter L. Tokarsky, Alexandr A. Konovalenko, S. N. Yerin, I. N. Bubnov
    Abstract:

    PACS number: 84.40.Ba Purpose: theoretical and experimental investigations of sensitivity by the signal-to-noise ratio criterion active antenna used as a phased Array Element of the GURT radio telescope of new generation. Design/methodology/approach: A mathematical model of active antenna is proposed, the technique of its application for calculation of the active phased Array Element sensitivity being described. Findings: Numerical and experimental studies of the temperatures of external and internal noises at the active phased Array Element output of the GURT radio telescope are carried out, as well as Element sensitivity estimated over a wide frequency range from 10 to 80 MHz. Conclusions: The obtained agreement between the results of computation and experiment points to correctness of the proposed technique of calculating the sensitivity of active antennas, and the results of studies of the phased Array Element confirm the possibility of its effective use in construction of the antenna system for the GURT radio telescope. Key words:  radio telescope, phased antenna Array, active antenna, signal-to-noise ratio Manuscript submitted 15.02.2016 Radio phys. radio astron. 2016, 21(1): 48-57 REFERENCES 1. KRAUS, J. D., 1966. Radio Astronomy . New York, USA: McGraw-Hill. 2. DE VOS, M., GUNST, A. W. and NIJBOER, R., 2009. The LOFAR Telescope: System Architecture and Signal Processing. IEEE Proc . vol. 97, is. 8, pp. 1431–1437. DOI: https://doi.org/10.1109/JPROC.2009.2020509 3. ELLINGSON, S.,W., CLARKE, T. E., COHEN, A., CRAIG, J., KASSIM, N. E., PIHLSTROM, Y., RICKARD, L. J. and TAYLOR, G. B., 2009. The Long Wavelength Array. IEEE Proc . vol. 97, is. 8, pp. 1421–1430. DOI: https://doi.org/10.1109/JPROC.2009.2015683 4. ZARKA, P., TAGGER, M., DENIS, L., GIRARD, J. N., KONOVALENKO, A., ATEMKENG, M., ARNAUD, M., AZARIAN, S., BARSUGLIA, M., BONAFEDE, A., BOONE, F., BOSMA, A., BOYER, R., BRANCHESI, M., BRIAND, C., CECCONI, B., CELESTIN, S., CHARRIER, D., CHASSANDE-MOTTIN, E., COFFRE, A., COGNARD, I., COMBES, F., CORBEL, S., COURTE, C., DABBECH, A.,. DAIBOO, S, DALLIER, R., DUMEZ-VIOU, C., EL KORSO, M. N., FALGARONE, E., FALKOVYCH, I., FERRARI, A., FERRARI, C., FERRIERE, K., FEVOTTE, C., FIALKOV, A., FULLEKRUG, M., GERARD E., GRIEsMEIER, J.-M., GUIDERDONI, B., GUILLEMOT, L., HESSELS, J.,. KOOPMANS, L, KONDRATIEV, V., LAMY, L., LANZ, T., LARZABAL, P., LEHNERT, M., LEVRIER, F., LOH, A., MACARIO, G., MAINTOUX, J.-J., MARTIN, L., MARY, D., MASSON, S., MIVILLE-DESCHENES, M.-A., OBEROI, D., PANCHENKO, M., PANDEY-POMMIER, M., PETITEAU, A., PINCON, J.-L., REVENU, B., RIBLE, F., RICHARD, C., RUCKER, H. O., SALOME, P., SEMELIN, B., SERYLAK, M., SMIRNOV, O., STAPPERS, B., TAFFOUREAU, C., TASSE, C., THEUREAU, G., TOKARSKY, P., TORCHINSKY S., ULYANOV, O., VAN DRIEL, W., VASYLIEVA, I., VAUBAILLON, J., VAZZA, F., VERGANI, S., WAS M., WEBER, R. and ZAKHARENKO V., 2015. NenuFAR: Instrument Description and Science Case. In: 10th International Conference on Antenna Theory and Techniques Proceedings . 21– 24 April 2015,Kharkiv,Ukraine, pp. 13–18. DOI: https://doi.org/10.1109/ICATT.2015.7136773 5. KONOVALENKO A. A., FALKOVICH I. S., GRIDIN A. A., TOKARSKY P. L. and YERIN S. N., 2012. UWB Active Antenna Array for Low Frequency Radio Astronomy. In: 6th International Conference on Ultrawideband and Ultrashort Impulse Signals Conference Proceedings . 17–21 Sept. 2012, Sevastopol, Ukraine, pp. 39–43. DOI: https://doi.org/10.1109/UWBUSIS.2012.6379725 6. IVASHINA M. V., MAASKANT R. and WOESTENBURG B., 2008. Equivalent System Representation to Model the Beam Sensitivity of Receiving Antenna Arrays. IEEE Antennas Wireless Propag. Lett . vol. 7, pp. 733–737. DOI: https://doi.org/10.1109/LAWP.2008.2006917 7. WIJNHOLDS S. J. and VAN CAPPELLEN W. A., 2011. Insitu antenna performance evaluation of the LOFAR phased Array radio telescope. IEEE Trans. Antennas Propag . vol. 59, no. 6, pp. 1981–1989. DOI: https://doi.org/10.1109/TAP.2011.2122225 8. ELLINGSON, S. W., 2011. Sensitivity of Antenna Arrays for Long-Wavelength Radio Astronomy. IEEE Trans. Antennas Propag . vol. 59, no. 6, pp. 1855–1863. DOI: https://doi.org/10.1109/TAP.2011.2122230 9.SAZONOV, D. M., 2015. MultiElement antenna systems. The matrix approach . Moscow: Radiotechnika-Press Publ. (in Russian). 10. TOKARSKY, P. L., 2006. Matrix Model of a Dissipative Antenna Array. Radiotekhnika. All-Ukr. Sci. Interdep. Mag . is. 146, pp. 156–170 (in Russian). 11. RAZEVIG, B. D. (ed.), POTAPOV, Yu. V. and KURUSHIN, A. A., 2003. Design of microwave devices using Microwave Office . Moskow: SOLON-Press Publ. (in Russian). 12. BABAK, L. I., 1980. Determination of microwave circuits noise characteristics. Radiotekhnika i Elektronika . vol. 25, no. 11, pp. 2380–2384 (in Russian). 13. KRYMKIN, V. V., 1971. The spectrum of background lowfrequencyradio emission. Radiophysics and Quantum Electronics . vol. 14, is. 2, pp. 161–164. DOI: https://doi.org/10.1007/BF01031395 14. MARKOV, G. T. and SAZONOV, D. M., 1975. Aerials , 2nd ed., Moscow: Energiya Publ. (in Russian). 15. 4nec2 – NEC based antenna modeler and optimizer by Arie Voors [online]. Available from: http://www.qsl.net/4nec2/

Peter L. Tokarsky - One of the best experts on this subject based on the ideXlab platform.

  • Effect of the ground screen on sensitivity of low-frequency radio telescope Array Element
    2017 XI International Conference on Antenna Theory and Techniques (ICATT), 2017
    Co-Authors: Peter L. Tokarsky, Alexandr A. Konovalenko, S. N. Yerin
    Abstract:

    The Giant Ukrainian Radio Telescope (GURT) is a new generation radio telescope with active phased antenna Array intended to operate within 10–80 MHz range. The radio telescope is being constructed now in Ukraine. The Array Elements are active antennas in form of flat wire dipoles integrated with low-noise preamplifiers. In the paper we present a comparative analysis of two GURT Array Element versions that differ in presence or absence of wire grid ground screen under the dipole. The analysis results are given and discussed.

  • Sensitivity of an Active Antenna Array Element for the Low-Frequency Radio Telescope GURT
    IEEE Transactions on Antennas and Propagation, 2017
    Co-Authors: Peter L. Tokarsky, Alexandr A. Konovalenko, S. N. Yerin
    Abstract:

    The recently developed new generation, low-frequency Giant Ukrainian Radio Telescope (GURT) is built nearby the well-known Ukrainian T-shaped Radio Telescope. The new facility employs a phased antenna Array composed of many subArrays of $5 \times 5$ active antenna Elements. In this paper, the parameters of the active antenna used as Array Element are studied, with special attention paid to sensitivity. The electrical and noise parameters are calculated using computer simulation and wave techniques for noise modeling of two-port networks. The results of numerical calculations of the sensitivity are given in terms of the sky noise dominance (SND) and system equivalent flux density of the GURT Element within 10–80 MHz. The calculated results are compared with in situ measurements.

  • Sensitivity of Active Phased Antenna Array Element of Gurt Radio Telescope
    Radio physics and radio astronomy, 2016
    Co-Authors: Peter L. Tokarsky, Alexandr A. Konovalenko, S. N. Yerin, I. N. Bubnov
    Abstract:

    PACS number: 84.40.Ba Purpose: theoretical and experimental investigations of sensitivity by the signal-to-noise ratio criterion active antenna used as a phased Array Element of the GURT radio telescope of new generation. Design/methodology/approach: A mathematical model of active antenna is proposed, the technique of its application for calculation of the active phased Array Element sensitivity being described. Findings: Numerical and experimental studies of the temperatures of external and internal noises at the active phased Array Element output of the GURT radio telescope are carried out, as well as Element sensitivity estimated over a wide frequency range from 10 to 80 MHz. Conclusions: The obtained agreement between the results of computation and experiment points to correctness of the proposed technique of calculating the sensitivity of active antennas, and the results of studies of the phased Array Element confirm the possibility of its effective use in construction of the antenna system for the GURT radio telescope. Key words:  radio telescope, phased antenna Array, active antenna, signal-to-noise ratio Manuscript submitted 15.02.2016 Radio phys. radio astron. 2016, 21(1): 48-57 REFERENCES 1. KRAUS, J. D., 1966. Radio Astronomy . New York, USA: McGraw-Hill. 2. DE VOS, M., GUNST, A. W. and NIJBOER, R., 2009. The LOFAR Telescope: System Architecture and Signal Processing. IEEE Proc . vol. 97, is. 8, pp. 1431–1437. DOI: https://doi.org/10.1109/JPROC.2009.2020509 3. ELLINGSON, S.,W., CLARKE, T. E., COHEN, A., CRAIG, J., KASSIM, N. E., PIHLSTROM, Y., RICKARD, L. J. and TAYLOR, G. B., 2009. The Long Wavelength Array. IEEE Proc . vol. 97, is. 8, pp. 1421–1430. DOI: https://doi.org/10.1109/JPROC.2009.2015683 4. ZARKA, P., TAGGER, M., DENIS, L., GIRARD, J. N., KONOVALENKO, A., ATEMKENG, M., ARNAUD, M., AZARIAN, S., BARSUGLIA, M., BONAFEDE, A., BOONE, F., BOSMA, A., BOYER, R., BRANCHESI, M., BRIAND, C., CECCONI, B., CELESTIN, S., CHARRIER, D., CHASSANDE-MOTTIN, E., COFFRE, A., COGNARD, I., COMBES, F., CORBEL, S., COURTE, C., DABBECH, A.,. DAIBOO, S, DALLIER, R., DUMEZ-VIOU, C., EL KORSO, M. N., FALGARONE, E., FALKOVYCH, I., FERRARI, A., FERRARI, C., FERRIERE, K., FEVOTTE, C., FIALKOV, A., FULLEKRUG, M., GERARD E., GRIEsMEIER, J.-M., GUIDERDONI, B., GUILLEMOT, L., HESSELS, J.,. KOOPMANS, L, KONDRATIEV, V., LAMY, L., LANZ, T., LARZABAL, P., LEHNERT, M., LEVRIER, F., LOH, A., MACARIO, G., MAINTOUX, J.-J., MARTIN, L., MARY, D., MASSON, S., MIVILLE-DESCHENES, M.-A., OBEROI, D., PANCHENKO, M., PANDEY-POMMIER, M., PETITEAU, A., PINCON, J.-L., REVENU, B., RIBLE, F., RICHARD, C., RUCKER, H. O., SALOME, P., SEMELIN, B., SERYLAK, M., SMIRNOV, O., STAPPERS, B., TAFFOUREAU, C., TASSE, C., THEUREAU, G., TOKARSKY, P., TORCHINSKY S., ULYANOV, O., VAN DRIEL, W., VASYLIEVA, I., VAUBAILLON, J., VAZZA, F., VERGANI, S., WAS M., WEBER, R. and ZAKHARENKO V., 2015. NenuFAR: Instrument Description and Science Case. In: 10th International Conference on Antenna Theory and Techniques Proceedings . 21– 24 April 2015,Kharkiv,Ukraine, pp. 13–18. DOI: https://doi.org/10.1109/ICATT.2015.7136773 5. KONOVALENKO A. A., FALKOVICH I. S., GRIDIN A. A., TOKARSKY P. L. and YERIN S. N., 2012. UWB Active Antenna Array for Low Frequency Radio Astronomy. In: 6th International Conference on Ultrawideband and Ultrashort Impulse Signals Conference Proceedings . 17–21 Sept. 2012, Sevastopol, Ukraine, pp. 39–43. DOI: https://doi.org/10.1109/UWBUSIS.2012.6379725 6. IVASHINA M. V., MAASKANT R. and WOESTENBURG B., 2008. Equivalent System Representation to Model the Beam Sensitivity of Receiving Antenna Arrays. IEEE Antennas Wireless Propag. Lett . vol. 7, pp. 733–737. DOI: https://doi.org/10.1109/LAWP.2008.2006917 7. WIJNHOLDS S. J. and VAN CAPPELLEN W. A., 2011. Insitu antenna performance evaluation of the LOFAR phased Array radio telescope. IEEE Trans. Antennas Propag . vol. 59, no. 6, pp. 1981–1989. DOI: https://doi.org/10.1109/TAP.2011.2122225 8. ELLINGSON, S. W., 2011. Sensitivity of Antenna Arrays for Long-Wavelength Radio Astronomy. IEEE Trans. Antennas Propag . vol. 59, no. 6, pp. 1855–1863. DOI: https://doi.org/10.1109/TAP.2011.2122230 9.SAZONOV, D. M., 2015. MultiElement antenna systems. The matrix approach . Moscow: Radiotechnika-Press Publ. (in Russian). 10. TOKARSKY, P. L., 2006. Matrix Model of a Dissipative Antenna Array. Radiotekhnika. All-Ukr. Sci. Interdep. Mag . is. 146, pp. 156–170 (in Russian). 11. RAZEVIG, B. D. (ed.), POTAPOV, Yu. V. and KURUSHIN, A. A., 2003. Design of microwave devices using Microwave Office . Moskow: SOLON-Press Publ. (in Russian). 12. BABAK, L. I., 1980. Determination of microwave circuits noise characteristics. Radiotekhnika i Elektronika . vol. 25, no. 11, pp. 2380–2384 (in Russian). 13. KRYMKIN, V. V., 1971. The spectrum of background lowfrequencyradio emission. Radiophysics and Quantum Electronics . vol. 14, is. 2, pp. 161–164. DOI: https://doi.org/10.1007/BF01031395 14. MARKOV, G. T. and SAZONOV, D. M., 1975. Aerials , 2nd ed., Moscow: Energiya Publ. (in Russian). 15. 4nec2 – NEC based antenna modeler and optimizer by Arie Voors [online]. Available from: http://www.qsl.net/4nec2/

Stan E. Dosso - One of the best experts on this subject based on the ideXlab platform.

  • Array Element localization using ship noise.
    The Journal of the Acoustical Society of America, 2009
    Co-Authors: Michael Morley, Stan E. Dosso, N. Ross Chapman
    Abstract:

    This paper describes a method of estimating hydrophone positions in a receiver Array using the noise from a passing ship. Relative arrival times of the ship-noise signal between pairs of hydrophones are obtained from several time windows of data (corresponding to different ship locations) by cross-correlating the band-pass filtered time series. The relative arrival times are used as data in an Array Element localization inversion to estimate both the hydrophone and ship locations based on iterated linearization of the acoustic ray equations. The inversion applies the method of regularization to include prior information such as approximate location estimates and uncertainties for the source and receivers and the expectation that the Array shape and∕or source tracks are smooth functions of position. Linearized and nonlinear (Monte Carlo) estimates of the position errors are in good agreement and indicate a high degree of confidence in the receiver positions (relative uncertainties of approximately 0.2m in ...

  • Bayesian localization and tracking with environmental and Array‐Element uncertainties.
    The Journal of the Acoustical Society of America, 2008
    Co-Authors: Stan E. Dosso, Dag Tollefsen, Michael J. Wilmut
    Abstract:

    This paper considers matched‐field source localization and tracking when environmental parameters and/or Array‐Element positions are not well known. A Bayesian formulation is applied in which source, Array, and environmental parameters are considered unknown random variables constrained by noisy acoustic data and by prior information on parameter values (e.g., physical limits for environmental properties and Element positions) and on interparameter relationships (e.g., limits on source speed and interElement spacing). The goal then is to extract source information from the posterior probability density (PPD). One approach is based on maximizing the PPD over all parameters to obtain optimal source locations. A key to solving this problem efficiently is that the VITERBI algorithm is applied to compute the highest‐probability source track for each environment/Array realization: this provides the optimal track, while requiring the optimization is applied only over the nuisance parameters. A second approach in...

  • Array Element localization accuracy and survey design
    Canadian Acoustics, 2005
    Co-Authors: Stan E. Dosso, Gordon R. Ebbeson
    Abstract:

    Accurate localization of the individual Elements of an underwater acoustic receiver Array is an important prerequisite to advanced Array processing applications. Array Element localization (AEL) methods are typically based on inverting acoustic arrival-time measurements from controlled sources at (approximately) known positions to the receivers to be localized. This paper presents and illustrates a general approach to AEL inversion and to AEL survey design based on quantifying the posterior receiverlocation uncertainty, taking into account uncertainties in the data, source locations, sound speed, and water depth. The inversion is based on a fast ray-tracing algorithm that employs Newton's method and the method of images to determine eigenrays for direct and reflected arrivals. The efficiency of this approach allows computationally intensive analysis such as Monte-Carlo appraisal and nonlinear optimization for designing optimal source configurations. These algorithms provide a rigorous approach that can be applied to examine all aspects of AEL accuracy and survey design, illustrated here by several examples. It is shown that synchronized AEL surveys (in which source transmission times are known) provide only a minor improvement over non-synchronized surveys (often much simpler logistically), and the difference can be made up by using more sources in an optimal configuration or by including additional arrivals. Including multiple-reflected arrivals improves receiver depth estimates (provided water depth is well known), but provides little improvement in horizontal localization.

  • Experimental validation of regularized Array Element localization
    The Journal of the Acoustical Society of America, 2004
    Co-Authors: Stan E. Dosso, Nicole E. Collison, Garry J. Heard, Ronald I. Verrall
    Abstract:

    This paper examines and validates regularized inversion for Array Element localization (AEL) by quantitative comparison of inversion results to direct measurements of receiver positions for a full-scale AEL survey. Regularized AEL treats both receiver and source positions as unknown parameters in a ray-based inversion; prior information on source/receiver positions, inter-receiver spacing in depth, and/or a smooth Array shape can be included, subject to statistically fitting the acoustic data. Uncertainties in the recovered receiver positions are estimated via Monte Carlo appraisal. To study this approach, a specially stabilized, two-dimensional receiver Array and a series of impulsive sources (imploding glass light bulbs) were deployed from shore-fast (motionless) Arctic sea ice. Sources and recordings were not synchronized in time, so AEL inversions are based on relative arrival times. Receiver positions were measured to an uncertainty of ∼5 cm in each dimension [9 cm in three dimensions (3D)] using nonacoustic (optical) methods. Average AEL errors (difference between measured receiver positions and inversion results) of 13 cm in depth, 27 cm in the horizontal, and 30 cm in 3D, as well as good agreement between the measured errors and estimated AEL uncertainties validate the regularized approach and provide benchmarks for acoustic AEL. Receiver-position errors are quantitatively investigated as a function of the number of sources, source-position errors, and different regularizations.

  • Array Element localization of a bottom moored hydrophone Array
    Canadian Acoustics, 2002
    Co-Authors: Matthew Barlee, Stan E. Dosso, Philip Schey
    Abstract:

    In ocean acoustics, rapidly deployable, autonomous, bottom moored hydrophone Arrays allow for quick, cost effective deployment, but result in poor knowledge of sensor positions. Because advanced Array processing techniques, such as Matched Beam Processing, are highly sensitive to errors in sensor location, an accurate assessment of hydrophone positions is necessary. This paper discusses Array Element localization (AEL) and its use in localizing the ULITE Array, a horizontal Array deployed in the Timor Sea during the 1998 RDS-2 trial. The ill-posed inverse problem of determining source (imploded light bulbs) and receiver positions from the relative arrival times of source transients is solved through regularized linearized inversion. The inversion solution fits the data to high precision and provides individual hydrophone position estimates that provide the smoothest Array shape that is consistent with the acoustic data.

Alexandr A. Konovalenko - One of the best experts on this subject based on the ideXlab platform.

  • Effect of the ground screen on sensitivity of low-frequency radio telescope Array Element
    2017 XI International Conference on Antenna Theory and Techniques (ICATT), 2017
    Co-Authors: Peter L. Tokarsky, Alexandr A. Konovalenko, S. N. Yerin
    Abstract:

    The Giant Ukrainian Radio Telescope (GURT) is a new generation radio telescope with active phased antenna Array intended to operate within 10–80 MHz range. The radio telescope is being constructed now in Ukraine. The Array Elements are active antennas in form of flat wire dipoles integrated with low-noise preamplifiers. In the paper we present a comparative analysis of two GURT Array Element versions that differ in presence or absence of wire grid ground screen under the dipole. The analysis results are given and discussed.

  • Sensitivity of an Active Antenna Array Element for the Low-Frequency Radio Telescope GURT
    IEEE Transactions on Antennas and Propagation, 2017
    Co-Authors: Peter L. Tokarsky, Alexandr A. Konovalenko, S. N. Yerin
    Abstract:

    The recently developed new generation, low-frequency Giant Ukrainian Radio Telescope (GURT) is built nearby the well-known Ukrainian T-shaped Radio Telescope. The new facility employs a phased antenna Array composed of many subArrays of $5 \times 5$ active antenna Elements. In this paper, the parameters of the active antenna used as Array Element are studied, with special attention paid to sensitivity. The electrical and noise parameters are calculated using computer simulation and wave techniques for noise modeling of two-port networks. The results of numerical calculations of the sensitivity are given in terms of the sky noise dominance (SND) and system equivalent flux density of the GURT Element within 10–80 MHz. The calculated results are compared with in situ measurements.

  • Sensitivity of Active Phased Antenna Array Element of Gurt Radio Telescope
    Radio physics and radio astronomy, 2016
    Co-Authors: Peter L. Tokarsky, Alexandr A. Konovalenko, S. N. Yerin, I. N. Bubnov
    Abstract:

    PACS number: 84.40.Ba Purpose: theoretical and experimental investigations of sensitivity by the signal-to-noise ratio criterion active antenna used as a phased Array Element of the GURT radio telescope of new generation. Design/methodology/approach: A mathematical model of active antenna is proposed, the technique of its application for calculation of the active phased Array Element sensitivity being described. Findings: Numerical and experimental studies of the temperatures of external and internal noises at the active phased Array Element output of the GURT radio telescope are carried out, as well as Element sensitivity estimated over a wide frequency range from 10 to 80 MHz. Conclusions: The obtained agreement between the results of computation and experiment points to correctness of the proposed technique of calculating the sensitivity of active antennas, and the results of studies of the phased Array Element confirm the possibility of its effective use in construction of the antenna system for the GURT radio telescope. Key words:  radio telescope, phased antenna Array, active antenna, signal-to-noise ratio Manuscript submitted 15.02.2016 Radio phys. radio astron. 2016, 21(1): 48-57 REFERENCES 1. KRAUS, J. D., 1966. Radio Astronomy . New York, USA: McGraw-Hill. 2. DE VOS, M., GUNST, A. W. and NIJBOER, R., 2009. The LOFAR Telescope: System Architecture and Signal Processing. IEEE Proc . vol. 97, is. 8, pp. 1431–1437. DOI: https://doi.org/10.1109/JPROC.2009.2020509 3. ELLINGSON, S.,W., CLARKE, T. E., COHEN, A., CRAIG, J., KASSIM, N. E., PIHLSTROM, Y., RICKARD, L. J. and TAYLOR, G. B., 2009. The Long Wavelength Array. IEEE Proc . vol. 97, is. 8, pp. 1421–1430. DOI: https://doi.org/10.1109/JPROC.2009.2015683 4. ZARKA, P., TAGGER, M., DENIS, L., GIRARD, J. N., KONOVALENKO, A., ATEMKENG, M., ARNAUD, M., AZARIAN, S., BARSUGLIA, M., BONAFEDE, A., BOONE, F., BOSMA, A., BOYER, R., BRANCHESI, M., BRIAND, C., CECCONI, B., CELESTIN, S., CHARRIER, D., CHASSANDE-MOTTIN, E., COFFRE, A., COGNARD, I., COMBES, F., CORBEL, S., COURTE, C., DABBECH, A.,. DAIBOO, S, DALLIER, R., DUMEZ-VIOU, C., EL KORSO, M. N., FALGARONE, E., FALKOVYCH, I., FERRARI, A., FERRARI, C., FERRIERE, K., FEVOTTE, C., FIALKOV, A., FULLEKRUG, M., GERARD E., GRIEsMEIER, J.-M., GUIDERDONI, B., GUILLEMOT, L., HESSELS, J.,. KOOPMANS, L, KONDRATIEV, V., LAMY, L., LANZ, T., LARZABAL, P., LEHNERT, M., LEVRIER, F., LOH, A., MACARIO, G., MAINTOUX, J.-J., MARTIN, L., MARY, D., MASSON, S., MIVILLE-DESCHENES, M.-A., OBEROI, D., PANCHENKO, M., PANDEY-POMMIER, M., PETITEAU, A., PINCON, J.-L., REVENU, B., RIBLE, F., RICHARD, C., RUCKER, H. O., SALOME, P., SEMELIN, B., SERYLAK, M., SMIRNOV, O., STAPPERS, B., TAFFOUREAU, C., TASSE, C., THEUREAU, G., TOKARSKY, P., TORCHINSKY S., ULYANOV, O., VAN DRIEL, W., VASYLIEVA, I., VAUBAILLON, J., VAZZA, F., VERGANI, S., WAS M., WEBER, R. and ZAKHARENKO V., 2015. NenuFAR: Instrument Description and Science Case. In: 10th International Conference on Antenna Theory and Techniques Proceedings . 21– 24 April 2015,Kharkiv,Ukraine, pp. 13–18. DOI: https://doi.org/10.1109/ICATT.2015.7136773 5. KONOVALENKO A. A., FALKOVICH I. S., GRIDIN A. A., TOKARSKY P. L. and YERIN S. N., 2012. UWB Active Antenna Array for Low Frequency Radio Astronomy. In: 6th International Conference on Ultrawideband and Ultrashort Impulse Signals Conference Proceedings . 17–21 Sept. 2012, Sevastopol, Ukraine, pp. 39–43. DOI: https://doi.org/10.1109/UWBUSIS.2012.6379725 6. IVASHINA M. V., MAASKANT R. and WOESTENBURG B., 2008. Equivalent System Representation to Model the Beam Sensitivity of Receiving Antenna Arrays. 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Wenwu Cao - One of the best experts on this subject based on the ideXlab platform.

  • Effect of kerf filler on the electromechanical coupling coefficient of an ultrasonic transducer Array Element
    Applied Physics Letters, 2007
    Co-Authors: Jungsoon Kim, Moojoon Kim, Wenwu Cao
    Abstract:

    Electromechanical coupling coefficient directly reflects the electromechanical energy conversion capability of a piezoelectric device. We show theoretically that the kerf filler in the ultrasonic Array transducer can degrade this coupling coefficient. A closed form expression has been derived that can quantitatively describe the electromechanical coupling coefficient of an ultrasonic transducer Array Element with arbitrary aspect ratio and having polymer kerf filler in between transducer Elements.

  • Electromechanical coupling coefficient of an ultrasonic Array Element
    Journal of Applied Physics, 2006
    Co-Authors: Moojoon Kim, Jungsoon Kim, Wenwu Cao
    Abstract:

    One of the most important parameters for characterizing piezoelectric materials is the so-called electromechanical coupling coefficient, k, which describes the electromechanical coupling strength. Although this parameter should be an intrinsic material parameter, it appears to depend on the aspect ratio of the resonator. There are three different values defined for three extreme geometries, k33, k33′, and kt, and they differ by more than 50%. Unfortunately, these three values cannot describe resonators of general geometries and also create conceptual confusion. Here, we provide a unified formula that will accurately describe the coupling coefficient of rectangular slender bar transducer Array Element with any aspect ratio.