Results 101 to 110 of about 240,501 (293)

Generation of Ultrastable Microwaves via Optical Frequency Division

, 2011
There has been increased interest in the use and manipulation of optical fields to address challenging problems that have traditionally been approached with microwave electronics.
A Bartels, A. Ludlow, AA Savchenkov, AD Ludlow, AG Mann, BC Young, C. W. Oates, CR Locke, EN Ivanov, F. Quinlan, G Santarelli, GC Valley, J Capmany, J Millo, J Millo, J Taylor, J. C. Bergquist, J. Taylor, JA Scheer, JJ McFerran, L-S Ma, M. S. Kirchner, N. Lemke, S Doeleman, S Grop, S Grop, S Weyers, S. A. Diddams, SA Diddams, SA Webster, ST Dawkins, T. M. Fortier, T. Rosenband, TM Fortier, W Zhang, Y. Jiang, YY Jiang   +36 more
core   +1 more source

Physics‐Embedded Neural Network: A Novel Approach to Design Polymeric Materials

Advanced Science, EarlyView.
Traditional black‐box models for polymer mechanics rely solely on data and lack physical interpretability. This work presents a physics‐embedded neural network (PENN) that integrates constitutive equations into machine learning. The approach ensures reliable stress predictions, provides interpretable parameters, and enables performance‐driven, inverse ...
Siqi Zhan, Hengheng Zhao, Haotian Wang, Zhanjie Liu, Qian Li, Weifeng Zhang, Qingsong Zhao, Liqun Zhang, Jun Liu   +8 more
wiley   +1 more source

Investigation of Coupling Mechanisms for Efficient High Power and Low Phase Noise E-Band Quadrature VCOs in 130nm SiGe

IEEE Journal of Microwaves
This article compares two SiGe Colpitts quadrature voltage-controlled oscillators (QVCO) with different coupling techniques in the low E-Band, intended to be used as signal sources for push-push frequency doublers.
David Starke, Sven Thomas, Christian Bredendiek, Klaus Aufinger, Nils Pohl   +4 more
doaj   +1 more source

High-resolution three-dimensional imaging radar [PDF]

, 2010
A three-dimensional imaging radar operating at high frequency e.g., 670 GHz, is disclosed. The active target illumination inherent in radar solves the problem of low signal power and narrow-band detection by using submillimeter heterodyne mixer receivers.
Chattopadhyay, Goutam, Cooper, Ken B., Dengler, Robert J., Mehdi, Imran, Schlecht, Erich T., Siegel, Peter H., Skalare, Anders J.   +6 more
core   +1 more source

Beyond the horizon: High Frequency Surface Wave Radar

1st MARITIME SITUATIONAL AWARENESS WORKSHOP (MSAW 2019), 2019
In this paper, we present a high-level view of the High Frequency Surface Wave Radar developed for the Radars for long distance maritime surveillance and SAR operations (RANGER) project ([1]). The over-the-horizon radar proposes a new system architecture, with new waveforms, new processing methods, and new antenna concepts to provide solutions to meet ...
Lamole Frédéric, Jacquin François, Rigal Gilles   +2 more
openaire   +1 more source

Dirac Surface‐State Driven Broad Spectral Band Low Quantum Energy Photoresponse in Quaternary Topological BiSbSe2Te

Advanced Science, EarlyView.
Quaternary topological BiSbSe2Te are synthesized and demonstrates a broad spectral band photoresponse, ranging from infrared to terahertz and to millimeter waves, with a particular excellence on detection of low quantum energy terahertz photons. The observed photoresponse is attributed to the excitation of plasmonic nonequilibrium electrons originating
Tianning Zhang, Jinchao Tong, Jiantian Zhang, Peng Yu, Heng Luo, Luo Yan, Boyu Yang, Tiantian Huang, Junhui Ran, Yan Chen, Liujiang Zhou, Xin Chen, Ning Dai, Jianlu Wang, Junhao Chu   +14 more
wiley   +1 more source

High-Accuracy Linearity Measurement of Broadband Frequency Chirps

IEEE Open Journal of Instrumentation and Measurement
High-resolution radar systems use fast and broadband frequency chirps to enable high resolutions with short measurement times. One challenge in these radar systems is minimizing the linearity error in the generated frequency chirps, directly influencing ...
Bent Walther, Andre Froehly, Thomas Musch, Marcel van Delden   +3 more
doaj   +1 more source

Radio disturbance of high frequency surface wave radar

Electronics Letters, 2004
Based on a dual-polarisation high frequency surface wave radar system, main characteristics and performance of radio are described, and a new polarisation filter (adaptive null phase-shift polarisation (ANPSP)) is proposed. Filtering the disturbance in each pulse and keeping the original phases of the targets, more than 50 dB SIR improvement is ...
M. Xingpeng, L. Yongtan, D. Weibo
openaire   +1 more source

Elimination of range-aliased echoes in the VHF radars [PDF]

Very high frequency radars designed to measure tropospheric wind profiles usually detect scattering to a maximum height of about 20 km. If the antenna elevation angle is 45 degrees or more above the horizon, the maximum range of interest is less than 30 ...
Strauch, R. G.
core   +1 more source

Ultra-Wide Swath SAR Imaging With Continuous PRF Variation [PDF]

, 2010
Innovative multi-channel synthetic aperture radar (SAR) concepts enable high-resolution wide-swath imaging, but the antenna length typically restricts the achievable swath width.
Gebert, Nicolas, Krieger, Gerhard
core