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31 results on '"Coumar, S."'

3. Fabrication and characterization of super-polished wedged borosilicate nano-cells

Author

Peyrot, T., Beurthe, Ch., Coumar, S., Roulliay, M., Perronet, K., Bonnay, P., Adams, C. S., Browaeys, A., and Sortais, Y. R. P.

Subjects
Physics - Atomic Physics, Physics - Applied Physics, Physics - Optics
Abstract

We report on the fabrication of an all-glass vapor cell with a thickness varying linearly between (exactly) 0 and ~ 1 {\mu}m. The cell is made in Borofloat glass that allows super polish roughness, a full optical bonding assembling and easy filling with alkali vapors. We detail the challenging manufacture steps and present experimental spectra resulting from off-axis fluorescence and transmission spectroscopy of the Cesium D1 line. The very small surface roughness of 1 Angstr\"om rms is promising to investigate the atom-surface interaction or to minimize parasite stray light., Comment: 5 pages, 5 figures

Published
2019
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9. Miniaturized metallic symmetrical resonator backed CPW inspired dual band filter using Meander line for 5G mm‐wave applications.

Author

Coumar, S. Oudaya

Subjects
*COPLANAR waveguides, *RESONATORS, *INSERTION loss (Telecommunication), *5G networks, *UNIFORM spaces
Abstract

An ultra‐miniaturized symmetrical resonator backed coplanar waveguide based dual band pass filter using Meander line for 5G mm‐wave applications is presented. Meander line CPW structure with ultra miniaturized size was designed, investigated and its equivalent circuit was extracted using theoretical and experimental results to explore basic RF characteristics. The resonator at the back side of the substrate is symmetrical in both horizontal and vertical plane. This resonator is electrically coupled with the Meander line structure in the conducting plane. Symmetrical resonator structure coupled with open stubs on both sides on ground plane and Meander line structure with uniform spacing implemented at the conducting layer constitutes the metallic backed Co‐Planar waveguide based dual band filter. By using Meander line, the overall size of the communication devices has been reduced in large scale. The combination of symmetrical resonator and Meander line structure produces the overall bandwidth from (1 to 30) GHz. 5G mm‐wave filter operates in two bands; Band I operates from (1 to 14.2) GHz with insertion loss −1.8 dB and return loss −34 dB with fractional bandwidth of 73.6%; Band II operates from (16.2 to 30) GHz with insertion loss −1.2 dB, return loss −30 dB and fractional bandwidth of 59.7%. The overall filter circuit geometry is (5 × 5 × 1.6) mm and in terms of wavelength: (0.52 × 0.52) λg. [ABSTRACT FROM AUTHOR]

Published
2023
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10. The Solar Orbiter EUI instrument: The Extreme Ultraviolet Imager (Corrigendum)

Author

Rochus, P., primary, Auchère, F., additional, Berghmans, D., additional, Harra, L., additional, Schmutz, W., additional, Schühle, U., additional, Addison, P., additional, Appourchaux, T., additional, Aznar Cuadrado, R., additional, Baker, D., additional, Barbay, J., additional, Bates, D., additional, BenMoussa, A., additional, Bergmann, M., additional, Beurthe, C., additional, Borgo, B., additional, Bonte, K., additional, Bouzit, M., additional, Bradley, L., additional, Büchel, V., additional, Buchlin, E., additional, Büchner, J., additional, Cabé, F., additional, Cadiergues, L., additional, Chaigneau, M., additional, Chares, B., additional, Choque Cortez, C., additional, Coker, P., additional, Condamin, M., additional, Coumar, S., additional, Curdt, W., additional, Cutler, J., additional, Davies, D., additional, Davison, G., additional, Defise, J.-M., additional, Del Zanna, G., additional, Delmotte, F., additional, Delouille, V., additional, Dolla, L., additional, Dumesnil, C., additional, Dürig, F., additional, Enge, R., additional, François, S., additional, Fourmond, J.-J., additional, Gillis, J.-M., additional, Giordanengo, B., additional, Gissot, S., additional, Green, L. M., additional, Guerreiro, N., additional, Guilbaud, A., additional, Gyo, M., additional, Haberreiter, M., additional, Hafiz, A., additional, Hailey, M., additional, Halain, J.-P., additional, Hansotte, J., additional, Hecquet, C., additional, Heerlein, K., additional, Hellin, M.-L., additional, Hemsley, S., additional, Hermans, A., additional, Hervier, V., additional, Hochedez, J.-F., additional, Houbrechts, Y., additional, Ihsan, K., additional, Jacques, L., additional, Jérôme, A., additional, Jones, J., additional, Kahle, M., additional, Kennedy, T., additional, Klaproth, M., additional, Kolleck, M., additional, Koller, S., additional, Kotsialos, E., additional, Kraaikamp, E., additional, Langer, P., additional, Lawrenson, A., additional, Le Clech’, J.-C., additional, Lenaerts, C., additional, Liebecq, S., additional, Linder, D., additional, Long, D. M., additional, Mampaey, B., additional, Markiewicz-Innes, D., additional, Marquet, B., additional, Marsch, E., additional, Matthews, S., additional, Mazy, E., additional, Mazzoli, A., additional, Meining, S., additional, Meltchakov, E., additional, Mercier, R., additional, Meyer, S., additional, Monecke, M., additional, Monfort, F., additional, Morinaud, G., additional, Moron, F., additional, Mountney, L., additional, Müller, R., additional, Nicula, B., additional, Parenti, S., additional, Peter, H., additional, Pfiffner, D., additional, Philippon, A., additional, Phillips, I., additional, Plesseria, J.-Y., additional, Pylyser, E., additional, Rabecki, F., additional, Ravet-Krill, M.-F., additional, Rebellato, J., additional, Renotte, E., additional, Rodriguez, L., additional, Roose, S., additional, Rosin, J., additional, Rossi, L., additional, Roth, P., additional, Rouesnel, F., additional, Roulliay, M., additional, Rousseau, A., additional, Ruane, K., additional, Scanlan, J., additional, Schlatter, P., additional, Seaton, D. B., additional, Silliman, K., additional, Smit, S., additional, Smith, P. J., additional, Solanki, S. K., additional, Spescha, M., additional, Spencer, A., additional, Stegen, K., additional, Stockman, Y., additional, Szwec, N., additional, Tamiatto, C., additional, Tandy, J., additional, Teriaca, L., additional, Theobald, C., additional, Tychon, I., additional, van Driel-Gesztelyi, L., additional, Verbeeck, C., additional, Vial, J.-C., additional, Werner, S., additional, West, M. J., additional, Westwood, D., additional, Wiegelmann, T., additional, Willis, G., additional, Winter, B., additional, Zerr, A., additional, Zhang, X., additional, and Zhukov, A. N., additional

Published
2022
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14. The Solar Orbiter EUI instrument: The Extreme Ultraviolet Imager

Author

Rochus, P., primary, Auchère, F., additional, Berghmans, D., additional, Harra, L., additional, Schmutz, W., additional, Schühle, U., additional, Addison, P., additional, Appourchaux, T., additional, Aznar Cuadrado, R., additional, Baker, D., additional, Barbay, J., additional, Bates, D., additional, BenMoussa, A., additional, Bergmann, M., additional, Beurthe, C., additional, Borgo, B., additional, Bonte, K., additional, Bouzit, M., additional, Bradley, L., additional, Büchel, V., additional, Buchlin, E., additional, Büchner, J., additional, Cabé, F., additional, Cadiergues, L., additional, Chaigneau, M., additional, Chares, B., additional, Choque Cortez, C., additional, Coker, P., additional, Condamin, M., additional, Coumar, S., additional, Curdt, W., additional, Cutler, J., additional, Davies, D., additional, Davison, G., additional, Defise, J.-M., additional, Del Zanna, G., additional, Delmotte, F., additional, Delouille, V., additional, Dolla, L., additional, Dumesnil, C., additional, Dürig, F., additional, Enge, R., additional, François, S., additional, Fourmond, J.-J., additional, Gillis, J.-M., additional, Giordanengo, B., additional, Gissot, S., additional, Green, L. M., additional, Guerreiro, N., additional, Guilbaud, A., additional, Gyo, M., additional, Haberreiter, M., additional, Hafiz, A., additional, Hailey, M., additional, Halain, J.-P., additional, Hansotte, J., additional, Hecquet, C., additional, Heerlein, K., additional, Hellin, M.-L., additional, Hemsley, S., additional, Hermans, A., additional, Hervier, V., additional, Hochedez, J.-F., additional, Houbrechts, Y., additional, Ihsan, K., additional, Jacques, L., additional, Jérôme, A., additional, Jones, J., additional, Kahle, M., additional, Kennedy, T., additional, Klaproth, M., additional, Kolleck, M., additional, Koller, S., additional, Kotsialos, E., additional, Kraaikamp, E., additional, Langer, P., additional, Lawrenson, A., additional, Le Clech’, J.-C., additional, Lenaerts, C., additional, Liebecq, S., additional, Linder, D., additional, Long, D. M., additional, Mampaey, B., additional, Markiewicz-Innes, D., additional, Marquet, B., additional, Marsch, E., additional, Matthews, S., additional, Mazy, E., additional, Mazzoli, A., additional, Meining, S., additional, Meltchakov, E., additional, Mercier, R., additional, Meyer, S., additional, Monecke, M., additional, Monfort, F., additional, Morinaud, G., additional, Moron, F., additional, Mountney, L., additional, Müller, R., additional, Nicula, B., additional, Parenti, S., additional, Peter, H., additional, Pfiffner, D., additional, Philippon, A., additional, Phillips, I., additional, Plesseria, J.-Y., additional, Pylyser, E., additional, Rabecki, F., additional, Ravet-Krill, M.-F., additional, Rebellato, J., additional, Renotte, E., additional, Rodriguez, L., additional, Roose, S., additional, Rosin, J., additional, Rossi, L., additional, Roth, P., additional, Rouesnel, F., additional, Roulliay, M., additional, Rousseau, A., additional, Ruane, K., additional, Scanlan, J., additional, Schlatter, P., additional, Seaton, D. B., additional, Silliman, K., additional, Smit, S., additional, Smith, P. J., additional, Solanki, S. K., additional, Spescha, M., additional, Spencer, A., additional, Stegen, K., additional, Stockman, Y., additional, Szwec, N., additional, Tamiatto, C., additional, Tandy, J., additional, Teriaca, L., additional, Theobald, C., additional, Tychon, I., additional, van Driel-Gesztelyi, L., additional, Verbeeck, C., additional, Vial, J.-C., additional, Werner, S., additional, West, M. J., additional, Westwood, D., additional, Wiegelmann, T., additional, Willis, G., additional, Winter, B., additional, Zerr, A., additional, Zhang, X., additional, and Zhukov, A. N., additional

Published
2020
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17. Metallic ring backed co-planar waveguide satellite L-band and S-band low Pass filter.

Author

coumar, S. Oudaya and S., Tamilselvan

Subjects
*COPLANAR waveguides, *ELECTROMAGNETISM, *MICROSTRIP transmission lines, *BANDWIDTHS, *WAVEGUIDES
Abstract

A metallic ring pattern backed co-planar waveguide low-pass filter (LPF) for satellite band applications is proposed in this work. A novel ring metallic pattern at ground plane and inter-digital coupling at conductor plane plays a significant role in this filter design. Design, Simulation and fabrication of Satellite band LPF characteristics are deliberated in this work. The proposed Satellite band filter produces excellent bandwidth (0-4.3) GHz, hence the proposed filter will be the best for Satellite band applications such as L and S bands. The simulation analysis of proposed filter is done by electromagnetic solver. The return loss (RL), insertion loss (IL), group delay and phase of the filter are simulated and their performances are analysed and compared with measured results. The overall dimension of the filter is 39 mm×4.5 mm×1.6 mm on considering all elements. The fractional bandwidth of filter is calculated from the bandwidth and the centre frequency is obtained about 200%. The S parameter results of LPF such as RL (S11) is about -29.3 dB and IL (S21) is -0.98 dB is obtained in simulation whereas in measurement, the RL is nearly -25.10 dB and IL is -1.52 dB. [ABSTRACT FROM AUTHOR]

Published
2021
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19. Co-operative transmission assisted Interference Alignment (IA) Technique forImproving the Performance of Small Cell HetNetUsers.

Author

Prabakar, D., Coumar, S. Oudaya, and Ramadoss, P.

Subjects
CELL communication, DEGREES of freedom, SIGNAL classification
Abstract

Interference Alignment (IA) in Heterogeneous Networks (HetNets) is a challenging task due to the integration of diverse communicating equipments and wireless technologies. The channel access and allocation period of the communicating equipment's vary with time and frequency domain, creating less feasibility in IA.In a heterogeneous network with interoperable features, communication in small cell is rationalized by proper interference alignment in concurrent channel access and licensed spectrum usage. In this article we introduce a co-operative transmission assisted linear interference alignment (IA) technique for improving the spectral efficiency of small cell user equipment (UE). The proposed linear optimization based IA classifies the transmitted signal with the intermediate interference receiver signals. Based on the observation, the identical signal input vectors are classified to suppress interference at the receiver end. Besides, the non-identical signal vectors are independently classified to improve the degrees of freedom (DOF) as a measure for improving spectral efficiency of the UE. The performance of the proposed IA technique is assessed using simulations and the DOF, spectral efficiency is accounted for comparison. [ABSTRACT FROM AUTHOR]

Published
2021

21. Development of Band Reject Filter to Mitigate the effect of WLAN in UWB Receivers

Author

Tamilselvan S and Oudaya coumar S

Subjects
Physics, Filter design, Acoustics, Bandwidth (signal processing), Return loss, Insertion loss, Multi-band device, Stopband, Center frequency, Band-stop filter
Abstract

This paper is about a dual band single notch filter to eliminate the effect of WLAN in UWB range. A novel square resonator with interdigital coupling at both sides plays a key role in this filter design. Design and EM Simulation of the dual band notch filter's characteristics are discussed in this paper. The proposed dual band notch filter produces excellent bandwidth from 2 GHz to 5 GHz and from 5.5 GHz to 8 GHz. The filter rejects the band of frequency from 5 GHz to 5.5 GHz which is very narrow band in which the filter eliminates the effect of WLAN (IEEE 802.11a). Also the out band performance of the proposed dual band filter meets the requirement of FCC's mask. The simulation analysis of the proposed filter is performed by electromagnetic solver. The return loss, insertion loss, group delay and phase of the filter are simulated and their performances are analyzed. The overall dimension of the filter is achieved to be 39mm x 3.2mm x 1.6mm on accounting the above features. The fractional bandwidth of the notch filter is calculated from the bandwidth and the center frequency and it is obtained about 115%. The S parameter results of the filter such as return loss (S11) in stop band is about -24 dB and insertion loss (S21) is about -28 dB is obtained.

Published
2018
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31. CTH:YAG : from laser medium to luminescent concentrator.

Author

Lopez L, Pichon P, Druon F, Coumar S, Oriol C, Georges P, and Balembois F

Abstract

This work presents what we believe is a new way to use a CTH:YAG crystal for spontaneous emission instead of laser emission. The spontaneous emission is collected in one main direction thanks to a luminescent concentrator configuration. The CTH:YAG is indirectly LED-pumped by a Ce:YAG delivering 3.5 ms pulses at 10 Hz with an energy of 2 J in the visible (550-650 nm). In a configuration optimized for light extraction, the CTH:YAG luminescent concentrator provides a broadband emission between 1.8 µm and 2.1 µm with a unique combination of power (1 W) and brightness (21.2 W/cm 2 /sr) that could be useful for short-wave infrared (SWIR) lighting applications.

Published
2024
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