Results 271 to 280 of about 58,504 (315)
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Phased array of phased arrays for free space optical communications
2003 IEEE Aerospace Conference Proceedings (Cat. No.03TH8652), 2004An aperture composed of multiple small apertures has several advantages over a large continuous aperture when practical issues are included in the analysis. For example, a single bullet can easily produce a catastrophic failure of the laser communication link if all the optical gain for the transmitter (or receiver) is derived from a single large ...
S. Serati, J. Stockley
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Beam combining using a phased array of phased arrays (PAPA)
2004 IEEE Aerospace Conference Proceedings (IEEE Cat. No.04TH8720), 2005Mobile free space optical (MFSO) networks introduce new challenges for laser communication terminals. Network capabilities, such as packet routing where different information packets are sent to different locations, require switchable links. Also, switchable links are needed to route an information packet through different channels to the same ...
S. Serati, H. Masterson, A. Linnenberger
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IEEE Custom Integrated Circuits Conference 2006, 2006
This work comprises an array of 4 phase shifters and antennas operating at 60GHz for a beamforming system. Pass gates form the switching core for a phase selector circuit which is replicated to build up a vector modulator phase shifter. The final beam accuracy is better than 2deg for a 16-way system.
Sayf Alalusi, Robert W. Brodersen
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This work comprises an array of 4 phase shifters and antennas operating at 60GHz for a beamforming system. Pass gates form the switching core for a phase selector circuit which is replicated to build up a vector modulator phase shifter. The final beam accuracy is better than 2deg for a 16-way system.
Sayf Alalusi, Robert W. Brodersen
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Journal of Combinatorial Designs, 2013
AbstractA 3‐phase Barker array is a matrix of third roots of unity for which all out‐of‐phase aperiodic autocorrelations have magnitude 0 or 1. The only known truly two‐dimensional 3‐phase Barker arrays have size 2 × 2 or 3 × 3. We use a mixture of combinatorial arguments and algebraic number theory to establish severe restrictions on the size of a 3 ...
Bell, Jason P. +4 more
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AbstractA 3‐phase Barker array is a matrix of third roots of unity for which all out‐of‐phase aperiodic autocorrelations have magnitude 0 or 1. The only known truly two‐dimensional 3‐phase Barker arrays have size 2 × 2 or 3 × 3. We use a mixture of combinatorial arguments and algebraic number theory to establish severe restrictions on the size of a 3 ...
Bell, Jason P. +4 more
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Compound Scanning with a Phased Array
Ultrasonic Imaging, 1982Compound scans made with a dynamically focussed phased array system have been produced in real time. The scanner, intended for abdominal imaging, has a large field of view. The compounding improves the acquisition of echoes from specular targets by changing the orientation of the insonifying beam and also reduces the speckle noise in grey scale images.
D P, Shattuck, O T, von Ramm
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Modeling of phased array transducers
The Journal of the Acoustical Society of America, 2005Phased array transducers are multi-element transducers, where different elements are activated with different time delays. The advantage of these transducers is that no mechanical movement of the transducer is needed to scan an object. Focusing and beam steering is obtained simply by adjusting the time delay.
Rais, Ahmad +2 more
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Applied Optics, 2014
We demonstrate a ladar with 0.5 m class range resolution obtained by integrating a continuous-wave optical phased-array transmitter with a Geiger-mode avalanche photodiode receiver array. In contrast with conventional ladar systems, an array of continuous-wave sources is used to effectively pulse illuminate a target by electro-optically steering far ...
Juan, Montoya +3 more
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We demonstrate a ladar with 0.5 m class range resolution obtained by integrating a continuous-wave optical phased-array transmitter with a Geiger-mode avalanche photodiode receiver array. In contrast with conventional ladar systems, an array of continuous-wave sources is used to effectively pulse illuminate a target by electro-optically steering far ...
Juan, Montoya +3 more
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Optical phased array technology
Proceedings of the IEEE, 1996Optical phased arrays represent an enabling new technology that makes possible simple affordable, lightweight, optical sensors offering very precise stabilization, random-access pointing programmable multiple simultaneous beams, a dynamic focus/defocus capability, and moderate to excellent optical power handling capability.
Paul F. McManamon +10 more
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Phased arrays with sub-array architecture
Proceedings 2000 IEEE International Conference on Phased Array Systems and Technology (Cat. No.00TH8510), 2002This paper presents a simplified true time delay beam steering at the element level which is no more complex than using a phase shifter at each element of the sub-array. The architecture described here makes multiple use of switched time-delays and thereby significantly reduces the complexity.
J.B.L. Rao +4 more
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Optimal Phase-Matching Strategy for Beam Scanning of Sub-Arrayed Phased Arrays
IEEE Transactions on Antennas and Propagation, 2019The design of phased array antennas generating two functional beams is addressed here. The first/primary beam is fixed and it is generated at the element level (EL) through the complex (amplitude and phase) weighting coefficients, while the second/secondary one is synthesized at the subarray level by aggregating the array elements into nonoverlapped ...
Rocca, P. +4 more
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