Beam steering

About: Beam steering is a research topic. Over the lifetime, 6683 publications have been published within this topic receiving 84061 citations. The topic is also known as: beamsteering & beam-steering.

Phased Array Antennas

Abstract: Preface to the First Edition. Preface to the Second Edition. 1 Introduction. 1.1 Array Background. 1.2 Systems Factors. 1.3 Annotated Reference Sources. References. 2 Basic Array Characteristics. 2.1 Uniformly Excited Linear Arrays. 2.2 Planar Arrays. 2.3 Beam Steering and Quantization Lobes. 2.4 Directivity. References. 3 Linear Array Pattern Synthesis. 3.1 Introduction. 3.2 Dolph Chebyshev Arrays. 3.3 Taylor One-Parameter Distribution. 3.4 Taylor N-Bar Aperture Distribution. 3.5 Low-Sidelobe Distributions. 3.6 Villeneuve N-Bar Array Distribution. 3.7 Difference Patterns. 3.8 Sidelobe Envelope Shaping. 3.9 Shaped Beam Synthesis. 3.10 Thinned Arrays. Acknowledgment. References. 4 Planar and Circular Array Pattern Synthesis. 4.1 Circular Planar Arrays. 4.2 Noncircular Apertures. Acknowledgment. References. 5 Array Elements. 5.1 Dipoles. 5.2 Waveguide Slots. 5.3 TEM Horns. 5.4 Microstrip Patches and Dipoles. Acknowledgments. References. 6 Array Feeds. 6.1 Series Feeds. 6.2 Shunt (Parallel) Feeds. 6.3 Two-Dimensional Feeds. 6.4 Photonic Feed Systems. 6.5 Systematic Errors. Acknowledgments. References. 7 Mutual Coupling. 7.1 Introduction. 7.2 Fundamentals of Scanning Arrays. 7.3 Spatial Domain Approaches to Mutual Coupling. 7.4 Spectral Domain Approaches. 7.5 Scan Compensation and Blind Angles. Acknowledgment. References. 8 Finite Arrays. 8.1 Methods of Analysis. 8.2 Scan Performance of Small Arrays. 8.3 Finite-by-Infinite Array Gibbsian Model. References. 9 Superdirective Arrays. 9.1 Historical Notes. 9.2 Maximum Array Directivity. 9.3 Constrained Optimization. 9.4 Matching of Superdirective Arrays. References. 10 Multiple-Beam Antennas. 10.1 Introduction. 10.2 Beamformers. 10.3 Low Sidelobes and Beam Interpolation. 10.4 Beam Orthogonality. Acknowledgments. References. 11 Conformal Arrays. 11.1 Scope. 11.2 Ring Arrays. 11.3 Arrays on Cylinders. 11.4 Sector Arrays on Cylinders. 11.5 Arrays on Cones and Spheres. Acknowledgments. References. 12 Connected Arrays. 12.1 History of Connected Arrays. 12.2 Connected Array Principles. 12.3 Connected Dipole Currents. 12.4 Connection by Reactance. 12.5 Connected Array Extensions. References. 13 Reflectarrays and Retrodirective Arrays. 13.1 Reflectarrays. 13.2 Retrodirective Arrays. References. 14 Reflectors with Arrays. 14.1 Focal Plane Arrays. 14.2 Near-Field Electromagnetic Optics. References. 15 Measurements and Tolerances. 15.1 Measurement of Low-Sidelobe Patterns. 15.2 Array Diagnostics. 15.3 Waveguide Simulators. 15.4 Array Tolerances. Acknowledgment. References. Author Index. Subject Index.

Large-scale nanophotonic phased array

Abstract: A large-scale silicon nanophotonic phased array with more than 4,000 antennas is demonstrated using a state-of-the-art complementary metal-oxide–semiconductor (CMOS) process, enabling arbitrary holograms with tunability, which brings phased arrays to many new technological territories. Nanophotonic approaches allow the construction of chip-scale arrays of optical nanoantennas capable of producing radiation patterns in the far field. This could be useful for a range of applications in communications, LADAR (laser detection and ranging) and three-dimensional holography. Until now this technology has been restricted to one-dimensional or small two-dimensional arrays. This paper reports the construction of a large-scale silicon nanophotonic phased array containing 4,096 optical nanoantennas balanced in power and aligned in phase. The array was used to generate a complex radiation pattern—the MIT logo—in the far field. The authors show that this type of nanophotonic phased array can be actively tuned, and in some cases the beam is steerable. Electromagnetic phased arrays at radio frequencies are well known and have enabled applications ranging from communications to radar, broadcasting and astronomy1. The ability to generate arbitrary radiation patterns with large-scale phased arrays has long been pursued. Although it is extremely expensive and cumbersome to deploy large-scale radiofrequency phased arrays2, optical phased arrays have a unique advantage in that the much shorter optical wavelength holds promise for large-scale integration3. However, the short optical wavelength also imposes stringent requirements on fabrication. As a consequence, although optical phased arrays have been studied with various platforms4,5,6,7,8 and recently with chip-scale nanophotonics9,10,11,12, all of the demonstrations so far are restricted to one-dimensional or small-scale two-dimensional arrays. Here we report the demonstration of a large-scale two-dimensional nanophotonic phased array (NPA), in which 64 × 64 (4,096) optical nanoantennas are densely integrated on a silicon chip within a footprint of 576 μm × 576 μm with all of the nanoantennas precisely balanced in power and aligned in phase to generate a designed, sophisticated radiation pattern in the far field. We also show that active phase tunability can be realized in the proposed NPA by demonstrating dynamic beam steering and shaping with an 8 × 8 array. This work demonstrates that a robust design, together with state-of-the-art complementary metal-oxide–semiconductor technology, allows large-scale NPAs to be implemented on compact and inexpensive nanophotonic chips. In turn, this enables arbitrary radiation pattern generation using NPAs and therefore extends the functionalities of phased arrays beyond conventional beam focusing and steering, opening up possibilities for large-scale deployment in applications such as communication, laser detection and ranging, three-dimensional holography and biomedical sciences, to name just a few.

Broadband Millimeter-Wave Propagation Measurements and Models Using Adaptive-Beam Antennas for Outdoor Urban Cellular Communications

Abstract: The spectrum crunch currently experienced by mobile cellular carriers makes the underutilized millimeter-wave frequency spectrum a sensible choice for next-generation cellular communications, particularly when considering the recent advances in low cost sub-terahertz/millimeter-wave complementary metal–oxide semiconductor circuitry. To date, however, little is known on how to design or deploy practical millimeter-wave cellular systems. In this paper, measurements for outdoor cellular channels at 38 GHz were made in an urban environment with a broadband (800-MHz RF passband bandwidth) sliding correlator channel sounder. Extensive angle of arrival, path loss, and multipath time delay spread measurements were conducted for steerable beam antennas of differing gains and beamwidths for a wide variety of transmitter and receiver locations. Coverage outages and the likelihood of outage with steerable antennas were also measured to determine how random receiver locations with differing antenna gains and link budgets could perform in future cellular systems. This paper provides measurements and models that may be used to design future fifth-generation millimeter-wave cellular networks and gives insight into antenna beam steering algorithms for these systems.

Space-time-coding digital metasurfaces

Abstract: The recently proposed digital coding metasurfaces make it possible to control electromagnetic (EM) waves in real time, and allow the implementation of many different functionalities in a programmable way. However, current configurations are only space-encoded, and do not exploit the temporal dimension. Here, we propose a general theory of space-time modulated digital coding metasurfaces to obtain simultaneous manipulations of EM waves in both space and frequency domains, i.e., to control the propagation direction and harmonic power distribution simultaneously. As proof-of-principle application examples, we consider harmonic beam steering, beam shaping, and scattering-signature control. For validation, we realize a prototype controlled by a field-programmable gate array, which implements the harmonic beam steering via an optimized space-time coding sequence. Numerical and experimental results, in good agreement, demonstrate good performance of the proposed approach, with potential applications to diverse fields such as wireless communications, cognitive radars, adaptive beamforming, holographic imaging.

Reconfigurable Antennas for Wireless and Space Applications

Abstract: Reconfigurable antennas, with the ability to radiate more than one pattern at different frequencies and polarizations, are necessary in modern telecommunication systems. The requirements for increased functionality (e.g., direction finding, beam steering, radar, control, and command) within a confined volume place a greater burden on today's transmitting and receiving systems. Reconfigurable antennas are a solution to this problem. This paper discusses the different reconfigurable components that can be used in an antenna to modify its structure and function. These reconfiguration techniques are either based on the integration of radio-frequency microelectromechanical systems (RF-MEMS), PIN diodes, varactors, photoconductive elements, or on the physical alteration of the antenna radiating structure, or on the use of smart materials such as ferrites and liquid crystals. Various activation mechanisms that can be used in each different reconfigurable implementation to achieve optimum performance are presented and discussed. Several examples of reconfigurable antennas for both terrestrial and space applications are highlighted, such as cognitive radio, multiple-input-multiple-output (MIMO) systems, and satellite communication.