Fact-checked by Grok 2 weeks ago

Beam steering

Beam steering is the process of directing the main beam of transmitted or received waves—such as electromagnetic, acoustic, or optical—in a desired direction.^[1] This technique enhances signal focus, improves efficiency, and reduces interference in various systems. It is achieved through methods including mechanical, electronic, and optical controls, with applications spanning radar, communications, medical imaging, and emerging technologies like LiDAR and terahertz sensing.^[2]

Fundamentals

Definition and Principles

Beam steering is the process of controlling the direction of a beam, encompassing electromagnetic waves, acoustic waves, or particle streams, typically without requiring physical movement of the source or transducer.^[3] This technique enables precise directional manipulation, enhancing efficiency in applications ranging from signal transmission to imaging by focusing energy toward a target while minimizing dispersion.^[4] The fundamental principles of beam steering rely on wave interference, where constructive interference reinforces the beam in the desired direction and destructive interference suppresses it elsewhere. Phase shifting introduces controlled delays in the wavefront across multiple emitters or elements, altering the beam's propagation angle; amplitude control further refines the pattern by adjusting signal strengths to optimize focus. For instance, in electronic implementations like phased arrays, varying phase and amplitude across an array steers the beam electronically. Key performance metrics include beamwidth, which measures the angular span of the main lobe (often defined as the half-power beamwidth where intensity drops to half its maximum), directivity, quantifying how concentrated the beam is relative to an isotropic source, and sidelobes, which represent unwanted secondary radiation peaks that can degrade signal purity if not minimized.^[5]^[6]^[7]^[8] At its core, beam steering draws from Huygens' principle, which posits that every point on a wavefront serves as a source of secondary spherical wavelets, with the envelope of these wavelets forming the subsequent wavefront. By manipulating these secondary sources—through phase gradients or refractive index variations—the overall wavefront can be tilted or curved to redirect the beam. This principle underpins wavefront engineering for steering, as seen in metasurface designs that achieve reflectionless beam control. Historically, early concepts emerged in 19th-century optics with the development of diffraction gratings, where interference from periodic structures directed light into specific orders, laying groundwork for modern beam manipulation techniques; Joseph von Fraunhofer's 1821 invention of practical ruled gratings marked a pivotal advancement in precise angular control of optical beams.^[9]^[10]^[11]

Beam Formation and Control

Beam formation in phased arrays involves combining signals from multiple radiating elements to produce a coherent wavefront that concentrates energy into a directed beam. This is achieved through processes such as array factor computation, where the overall radiation pattern is the product of the individual element pattern and the array factor, which accounts for the geometry and excitation of the elements. For a uniform linear array with N elements spaced by distance d, the array factor AF is given by:

AF(\theta) = \frac{\sin\left(N \psi / 2\right)}{N \sin\left(\psi / 2\right)},

where \psi = k d \sin\theta + \Delta\phi, k = 2\pi / \lambda is the wavenumber, \theta is the angle from broadside, and \Delta\phi is the progressive phase shift between elements.^[7] Aperture synthesis extends this concept by effectively enlarging the aperture through coherent combination of signals from distributed elements or subarrays, enabling higher resolution beams without a physically large continuous aperture. This technique is particularly useful in radar systems, where subarray multiplexing in time or frequency synthesizes an equivalent large aperture for improved directivity.^[12] Control of the beam direction is primarily accomplished by introducing phase gradients, time delays, or frequency tuning across the array elements to steer the wavefront. The steering angle \theta for a linear array is determined by the relation \sin\theta = \frac{\lambda \Delta\phi}{2\pi d}, where \Delta\phi is the phase difference between adjacent elements, \lambda is the wavelength, and d is the element spacing; this assumes a progressive phase shift that aligns the wavefronts toward the desired direction.^[7] For broadband signals, time delays are preferred over phase shifters to avoid beam squint, as phase shifts are frequency-dependent and can distort the beam at off-center frequencies. Frequency tuning, such as in frequency-scanned arrays, steers the beam by exploiting dispersion in the feed network, where the beam angle varies with frequency.^[13] Key metrics in beam formation and control include directivity gain, which scales with the number of elements and aperture size but decreases with steering angle due to the effective projected aperture reducing as \cos\theta. For instance, at broadside (\theta = 0^\circ), maximum gain is achieved, but steering to \pm 60^\circ can reduce gain by up to 6 dB in typical arrays.^[14] A critical trade-off arises with grating lobes—unwanted secondary beams caused by spatial aliasing—which can be prevented by limiting element spacing to d < \lambda/2, ensuring no replicas enter the visible space (|\sin\theta| \leq 1) for full 360° coverage. Larger spacings (e.g., d = 0.67 \lambda) allow higher gain but confine steering to narrow angles, such as \pm 30^\circ, to avoid grating lobes.^[14] Simulations of beam patterns rely on far-field approximations, valid at distances r > 2D²/\lambda where D is the array diameter, to predict the array factor and total pattern without near-field complexities. The array factor equation is computed numerically to visualize main beam width (approximately \lambda / D radians), sidelobe levels (e.g., -13 dB for uniform amplitude), and steering effects, often using tools like MATLAB for iterative phase optimization. These models guide design by balancing gain, beamwidth, and lobe suppression through amplitude tapering, such as Dolph-Chebyshev weighting, which trades gain for lower sidelobes.^[15]

Techniques

Mechanical Methods

Mechanical beam steering involves the physical repositioning of antennas, transducers, or associated components to direct the beam of radiated energy, typically employing mechanisms such as gimbals, rotators, or mirrors to alter the beam's direction. These systems rely on mechanical actuators to adjust the orientation, enabling control over the beam's azimuth and elevation angles without relying on electronic phase manipulation.^[16] Common types include rotary joints, which facilitate continuous rotation for azimuth and elevation control by transmitting signals through slip rings or waveguides while allowing unrestricted motion.^[17] Servo-driven platforms, often powered by electric motors, provide precise positioning for larger structures, integrating feedback loops to maintain alignment under varying loads.^[18] Such configurations are exemplified in satellite dishes, where gimbaled mounts track geostationary satellites by mechanically adjusting the parabolic reflector, and in early radar systems, which used similar setups to scan for targets.^[16] In optical systems, mechanical beam steering is commonly achieved using rotating prisms, such as Risley prisms consisting of two independently rotatable wedge prisms to deflect and scan the beam over a wide angular range, or galvanometer-driven mirrors for high-speed, precise pointing in laser applications.^[19] These methods offer high precision for narrow beams, achieving angular accuracies on the order of arcminutes through robust mechanical design, making them suitable for applications requiring stable, long-duration pointing. Additionally, they exhibit power efficiency in low-frequency applications, as gimbal-steered antennas consume minimal electrical power compared to active electronic alternatives, primarily due to the absence of high-power phase shifters or amplifiers per element.^[20] However, limitations include slow response times, ranging from milliseconds for small adjustments to seconds for full sweeps, which restrict their use in dynamic scenarios. Mechanical wear from continuous motion also poses reliability issues, necessitating regular maintenance to mitigate friction and fatigue in bearings and joints.^[21] Historically, mechanical steering traces back to World War II-era searchlight systems, where radar-guided gimbals directed high-intensity beams to illuminate aircraft targets for anti-aircraft fire.^[22] In the 1950s, naval radar installations commonly employed gimbaled platforms for fire-control systems, allowing shipboard antennas to track surface and aerial threats amid sea motion.^[23] These early implementations laid the groundwork for modern mechanical methods, though they have largely been supplanted by electronic alternatives for faster response in contemporary systems.^[3]

Electronic and Phased Array Methods

Electronic beam steering techniques, particularly through phased arrays, enable rapid and precise control of electromagnetic waves in radio frequency (RF) and microwave systems by electronically adjusting the phase and amplitude of signals fed to individual antenna elements.^[24] A phased array consists of multiple radiating elements, such as patches or dipoles, arranged in a linear or planar configuration, where each element is equipped with independent phase shifters to introduce controlled phase differences. This setup produces constructive interference in the desired direction, forming a steerable beam without physical movement of the antenna structure.^[13] Unlike mechanical methods that rely on slow physical adjustments, electronic steering achieves instantaneous beam repositioning, making it suitable for dynamic applications. Key components of phased array systems include phase shifters, which alter the signal phase to direct the beam, and beamforming networks that distribute and combine signals across elements. Phase shifters commonly employ ferrite materials for non-reciprocal phase control in high-power scenarios, PIN diodes for fast switching in moderate-power setups, or microelectromechanical systems (MEMS) for low-loss, compact operation.^[25] The beam direction is mathematically described by the array factor (AF), which determines the radiation pattern:

AF = \sum_{n} e^{j (k d \sin \theta + \phi_n)}

where k = 2\pi / \lambda is the wave number, d is the element spacing, \theta is the steering angle from broadside, and \phi_n is the phase shift applied to the n-th element.^[13] Beamforming networks, often implemented as corporate feeds or Butler matrices, ensure uniform excitation to minimize sidelobes and optimize gain.^[26] Phased arrays are classified as passive or active electronically scanned arrays (AESAs). In passive arrays, a single transmitter and receiver connect to all elements via phase shifters, offering simplicity but limited power handling and grace degradation if a component fails.^[27] AESAs integrate transmit/receive modules (TRMs) with amplifiers at each element, enabling higher power output, better reliability through redundancy, and independent control for multiple simultaneous beams via digital beamforming.^[28] Digital beamforming processes signals in the digital domain post-analog-to-digital conversion, allowing adaptive nulling and multi-functionality but increasing computational demands.^[27] Performance advantages of phased arrays include beam scanning speeds on the order of microseconds, far exceeding mechanical systems, and wide-angle coverage typically up to ±60° from broadside before significant gain loss or grating lobes emerge.^[13] However, these systems suffer from high cost due to numerous TRMs and phase shifters, as well as design complexity from calibration and integration challenges.^[29] Mutual coupling between elements, which distorts the radiation pattern and reduces efficiency, is mitigated through techniques like decoupling structures, such as electromagnetic bandgap surfaces or optimized element spacing.^[30]

Optical and Acoustic Methods

Optical beam steering techniques leverage the properties of light waves to direct beams without mechanical movement, primarily through phase modulation and diffraction. Liquid crystal spatial light modulators (SLMs) achieve this by electrically controlling the birefringence of liquid crystals to impose phase patterns on an incoming wavefront, enabling holographic reconstruction for precise steering. These devices, utilizing nematic or ferroelectric liquid crystals, support applications in adaptive optics and structured illumination by dynamically adjusting phase delays across pixel arrays. Since the 1980s, LC-based SLMs have been pivotal for holographic beam steering in optical communications, offering resolutions up to thousands of pixels for complex wavefront shaping. Another key method involves acousto-optic deflectors (AODs), which use radiofrequency-driven sound waves in a crystal to create a moving diffraction grating via the acousto-optic effect. Under Bragg diffraction conditions, the incident light beam is deflected into the first order, with the steering angle determined by θ = sin⁻¹(Δf / f_B), where Δf is the acoustic frequency shift from the center frequency and f_B is the Bragg frequency defined as f_B = v_a / λ (with v_a the acoustic velocity and λ the optical wavelength). This allows random access steering speeds exceeding 10 kHz, though diffraction efficiency typically ranges from 50% to 80% depending on material and wavelength. Acoustic beam steering methods adapt similar principles to sound waves, focusing on control in fluids or solids for applications like underwater sensing. Phased transducer arrays consist of multiple piezoelectric elements where time delays or phase shifts are applied to the driving signals, constructively interfering waves in a desired direction to form and steer the beam electronically. This approach, analogous to RF phased arrays but scaled for acoustic wavelengths in the kHz to MHz range, enables dynamic focusing and sector scanning without physical repositioning. Time-reversal mirrors provide an alternative for focusing through inhomogeneous media by recording the scattered acoustic field from a source, time-reversing it, and re-emitting via a transducer array, thereby refocusing energy back to the origin due to acoustic reciprocity and time-reversal invariance. Pioneered in the early 1990s, this technique achieves subwavelength focusing even in chaotic environments. Beamforming in hydrophone arrays further supports receive-mode steering, where signal processing combines outputs from multiple sensors with weighted delays to enhance sensitivity in a steered direction, improving signal-to-noise ratios in noisy propagation media. Unique challenges in these methods arise from the wave nature of light and sound. Optical techniques demand nanoscale precision in phase control due to short wavelengths (hundreds of nanometers), making fabrication tolerances critical to avoid aberrations, while wavelength dependence limits broadband operation as steering angles vary inversely with λ. In acoustics, longer wavelengths (millimeters to meters) allow coarser structures but introduce propagation losses from absorption and scattering in media like water or tissue, attenuating beams over distance and requiring higher power for sustained steering. Integration with microelectromechanical systems (MEMS) addresses compactness in both domains; for optics, MEMS-tunable gratings or mirrors enable low-power, chip-scale SLM enhancements, while in acoustics, MEMS transducers facilitate miniaturized phased arrays for portable ultrasound devices. Representative examples illustrate these methods' practical impact. Holographic optical elements (HOEs), recorded as volume gratings in photosensitive materials, diffractively control laser beams by redirecting and focusing light into predefined patterns, offering fixed steering with high efficiency (>90%) for applications like laser scanning. In acoustics, medical ultrasound arrays emerged in the early 1970s as pioneering phased systems, replacing mechanical scanners with electronic steering to enable real-time B-mode imaging through sector scans up to 90 degrees.

Applications

In Radar and Communications

In radar systems, beam steering enables precise targeting and enhanced imaging capabilities. Synthetic aperture radar (SAR) utilizes steered beams to maintain illumination on specific targets, forming a longer synthetic aperture for high-resolution imaging, as demonstrated in spotlight SAR modes where the beam is electronically adjusted to extend dwell time on the area of interest.^[31] Weather radars employ phased array technology for rapid electronic scanning, allowing volumetric observations of atmospheric phenomena without mechanical rotation, which improves detection of fast-evolving storms.^[32] Active electronically scanned array (AESA) radars provide beam agility by generating multiple independent beams simultaneously, facilitating the tracking of numerous targets across wide sectors with reduced scan times.^[33] In wireless communications, beam steering is integral to massive multiple-input multiple-output (MIMO) systems in 5G and emerging 6G networks, where it directs narrow beams toward specific users to boost signal strength and capacity.^[34] This technique, often implemented via phased arrays, reduces interference in dense environments by focusing energy, as seen in millimeter-wave (mmWave) deployments that began scaling in mobile networks during the 2010s to support multi-gigabit speeds.^[35] Advanced applications include orbital angular momentum (OAM) multiplexing, where steered helical beams carrying distinct topological charges enable parallel data streams over free-space or mmWave links, increasing spectral efficiency.^[36] Beam steering enhances signal-to-noise ratio (SNR) by concentrating transmitted power and mitigates multipath effects, while spatial multiplexing allows simultaneous service to multiple users, scaling throughput in radar tracking and communication channels.^[37] However, rapid steering can introduce Doppler shifts that distort velocity measurements in radar, necessitating compensation algorithms to maintain accuracy during agile scans.^[38] Key milestones include the development of military phased array radars in the 1960s, such as the U.S. Advanced Research Projects Agency's passive arrays for anti-ballistic missile defense, which pioneered electronic steering for real-time threat response.^[39]

In Sonar and Medical Imaging

Beam steering plays a crucial role in sonar systems for underwater applications, enabling precise acoustic signal direction to map seabeds and detect objects. In multibeam echo sounders, electronic beam steering allows simultaneous transmission and reception of multiple beams across a swath, facilitating high-resolution bathymetric surveys by adjusting phase delays in transducer arrays to form beams at various angles. This technique, widely used in hydrographic mapping, compensates for sound attenuation in water by dynamically steering beams to maintain signal strength over distances up to several kilometers. Side-scan sonar employs steered arrays to generate fan-shaped acoustic beams that scan the seafloor laterally, producing detailed images of underwater terrain and wrecks through time-delayed signal processing. In naval systems, beamforming enhances noise rejection by steering nulls toward interference sources, improving target detection in reverberant environments like shallow waters. In medical imaging, ultrasound beam steering expands diagnostic capabilities by electronically directing acoustic waves without mechanical movement, essential for non-invasive visualization of internal structures. For 3D and 4D imaging, phased array transducers steer beams across a volume in real time, acquiring volumetric data sets that reconstruct dynamic tissue motion, such as fetal heartbeats, with resolutions down to 0.5 mm. Sector scanning in echocardiography uses beam steering to create pie-shaped images from a transesophageal or transthoracic probe, allowing assessment of cardiac valves and chambers by fanning beams up to 90 degrees. Tissue harmonic imaging leverages nonlinear acoustic propagation, where steered beams generate harmonics at twice the transmitted frequency, improving contrast in fatty or fluid-filled tissues by reducing clutter. Attenuation compensation is critical in both water and biological media, where higher frequencies (2-15 MHz) suffer greater loss; algorithms adjust gain and steering angles to equalize signal amplitude across depths. Regulatory standards ensure safety in ultrasound applications, with the FDA establishing spatial-peak temporal-average intensity limits at 430 mW/cm² for cardiac imaging to prevent thermal bioeffects from steered beams.^[40] Real-time steering enables rapid volumetric data acquisition at frame rates exceeding 30 Hz, supporting live 4D renders in portable devices. Developments in beam steering trace back to the 1980s, when phased array probes revolutionized cardiology by enabling catheter-based imaging without mechanical scanning, as demonstrated in early transesophageal echocardiography systems. Modern matrix arrays, with thousands of elements, facilitate volumetric steering in handheld ultrasound units, reducing size and cost while achieving real-time 3D visualization for point-of-care diagnostics. These advances build on acoustic beamforming principles, adapting them for dense media propagation.

In Optics and Laser Systems

Beam steering in optics and laser systems enables precise control of light propagation, essential for applications ranging from astronomical imaging to industrial processing. In adaptive optics for telescopes, deformable mirrors dynamically adjust wavefronts to correct atmospheric distortions, steering the beam to achieve near-diffraction-limited resolution. This technique, pioneered in the 1990s, has significantly enhanced ground-based observations; for instance, the Keck Telescope's adaptive optics system, operational since 1999, uses a 349-actuator deformable mirror to steer and focus laser guide star beams, improving image sharpness by factors of 10 or more in the near-infrared spectrum. Similarly, laser diode arrays in LIDAR systems steer collimated beams to scan environments for distance mapping, with phased arrays enabling rapid electronic deflection without mechanical parts. Laser applications leverage beam steering for high-precision tasks such as cutting and welding, where galvanometer scanners direct the beam across material surfaces at speeds up to several meters per second, ensuring uniform energy delivery and minimizing thermal distortion. In holography, spatial light modulators (SLMs) steer and shape beams to reconstruct three-dimensional images, with modern liquid crystal SLMs achieving steering efficiencies exceeding 90% by modulating phase patterns across the aperture. Femtosecond pulse steering in microscopy, often using acousto-optic deflectors, allows ultrafast scanning of biological samples, enabling two-photon excitation with sub-micron resolution and repetition rates in the MHz range. Recent advancements include metasurface gratings that enable ultra-thin beam steering with sub-wavelength thickness, offering compact alternatives to bulk optics for integration into photonic devices like displays. These flat nanostructures, typically fabricated on silicon substrates, provide polarization-dependent control, directing beams at angles up to 60 degrees with efficiencies around 80-90% in the visible range. Such innovations build on optical methods like phase modulation, facilitating applications in augmented reality headsets where wide-angle steering is crucial for immersive viewing.

Emerging Developments

Metamaterial-Based Steering

Metamaterials are artificially engineered composites composed of subwavelength structures that enable electromagnetic properties not found in natural materials, such as negative refractive index, which facilitates anomalous refraction for beam steering. These structures manipulate wavefronts by imparting abrupt phase discontinuities, allowing precise control over the direction of propagating waves. A foundational principle is the generalized Snell's law, which governs refraction at such interfaces:

\sin \theta_t = \frac{n_i}{n_t} \sin \theta_i + \frac{\lambda}{2\pi n_t} \frac{d\phi}{dx}

where \theta_i and \theta_t are the incident and transmitted angles, n_i and n_t are the refractive indices of the incident and transmitted media, \lambda is the wavelength, and d\phi/dx is the phase gradient along the interface. This equation, derived from phase-matching conditions, enables anomalous refraction angles beyond conventional limits, as demonstrated in early metasurface prototypes. Huygens metasurfaces represent an advanced class of these structures, incorporating co-located electric and magnetic dipoles to achieve high-efficiency, reflectionless wavefront control for full two-dimensional (2D) beam steering. By satisfying the Huygens condition—equal excitation of orthogonal dipoles—these metasurfaces minimize backscattering and support bidirectional phase gradients, enabling versatile manipulation of beam direction in both transverse dimensions. Implementations of tunable metasurfaces for dynamic beam steering often incorporate active materials like graphene or liquid crystals to modulate phase profiles electrically or optically.^[41] Graphene-based designs leverage gate-voltage control to achieve over 330° phase tunability, allowing rapid reconfiguration of steering angles in the mid-infrared range.^[42] Similarly, liquid crystal-integrated metasurfaces enable voltage-driven reorientation of molecular dipoles, facilitating beam deflection switching with efficiencies around 50% in the visible and near-infrared spectra.^[43] These approaches support broadband operation spanning from terahertz (THz) frequencies, where gap-plasmon structures achieve wide-angle steering over 0.8–1.2 THz, to the visible regime with dielectric nanoresonators maintaining functionality across 400–700 nm.^[44] Compared to bulky phased array systems, metamaterial-based steering offers flat, lightweight designs that reduce volume by orders of magnitude while eliminating mechanical components for faster response times.^[45] In 2010s research, these advantages were exemplified in related wave manipulation for stealth applications, such as broadband electromagnetic cloaks using transformation optics to bend waves around objects, achieving invisibility over 8–14 GHz bands.^[46] Despite these benefits, challenges persist, including inherent losses from metallic or dielectric components at optical wavelengths, and fabrication scalability issues arising from nanoscale patterning requirements, which limit production to small areas via electron-beam lithography.^[47] Efforts to mitigate these involve additive manufacturing techniques, though uniformity over large apertures remains constrained by material dispersion and alignment precision.^[48] Recent advances as of 2025 include switchable THz metasurfaces achieving near-perfect ordinary transmission efficiency for beam steering across broadband frequencies, and AI-powered adaptive metamaterials enabling reconfigurable optoelectronics with dynamic wavefront control.^[49]^[50]

AI and Adaptive Techniques

Artificial intelligence (AI) and adaptive techniques have revolutionized beam steering by enabling real-time optimization and self-correction in dynamic environments, particularly when integrated with phased array hardware to adjust beam patterns based on environmental feedback. Machine learning algorithms, such as neural networks, predict optimal beamforming coefficients to minimize sidelobes and enhance directivity, using physics-informed models that incorporate electromagnetic principles for accurate predictions without exhaustive simulations. For instance, physics-aware convolutional neural networks (PA-CNNs) have been employed to forecast antenna array weights, achieving improvements in beam accuracy compared to traditional methods in millimeter-wave systems. These approaches leverage training data from channel states and sensor inputs to dynamically adapt steering angles, reducing interference in congested spectra. Adaptive systems employ closed-loop mechanisms where sensors provide continuous feedback for self-correction, allowing beam steering to respond to channel variations or target movements. In automotive radars, situation-aware adaptive beamforming adjusts parameters in real-time based on environmental sensing, forming a feedback loop that enhances detection reliability in cluttered scenes. Reinforcement learning (RL) further advances this in 6G networks, where agents learn policies to optimize beam allocation amid mobility and blockages, outperforming conventional exhaustive search in spectral efficiency. Such techniques enable predictive adjustments, as seen in deep RL-driven resource management for cognitive radars, which adapt waveforms and beams to evolving threats while maintaining low probability of intercept. In medical imaging, AI-optimized ultrasound beam steering exemplifies personalized adaptation, using active inference models to infer and track fetal heart positions via power Doppler signals, enabling closed-loop transmit beamsteering that compensates for motion artifacts with sub-millimeter precision. Algorithms contribute to pattern synthesis by iteratively optimizing element excitations for desired null steering and beam shapes, particularly effective in subarray architectures for wideband applications. These methods offer significant benefits, including reduced computational load through edge AI deployment, which processes inferences locally to avoid latency spikes in distributed networks, significantly reducing processing time in beam prediction tasks. However, challenges persist, such as data privacy risks from sharing channel state information for model training and inherent latency in feedback loops, which can degrade performance in ultra-reliable low-latency scenarios unless mitigated by federated learning approaches. Overall, AI-driven adaptations enhance robustness but require careful balancing of accuracy, security, and real-time constraints. Recent developments as of 2025 include generative AI for beamforming in low-altitude platforms and enhanced MIMO antennas with adaptive beam steering using deep learning for improved channel capacity and interference mitigation.^[51]^[52]

References

[1]
[PDF] IEEE Standard Definitions of Terms for Antennas
Jun 1, 2012 · 2.44 beam steering. Changing the direction of the major lobe of a radiation pattern. 2.45 beamwidth. See: half-power beamwidth. 2.46 Beverage ...
[2]
https://www.researchgate.net/publication/382516185_A_Comprehensive_Review_for_Beam_Steering_Technology_From_Mechanical_Prisms_to_Space-Time_Metasurface
[3]
https://www.astrodynetdi.com/blog/beam-steering-basics
[4]
A Comprehensive Review for Beam Steering Technology
Beam steering technology refers to technologies aiming at altering the propagation direction of the main lobe in radiation scenarios.Missing: authoritative | Show results with:authoritative
[5]
https://www.eeworldonline.com/what-are-phased-array-antennas-and-how-do-they-work/
[6]
Beam Steering Technology of Optical Phased Array Based on ... - NIH
Feb 26, 2024 · In this work, the recent research progress in improving the beam steering performance of the OPA based on silicon photonic integrated chips was reviewed.
[7]
Beam Steering Basics - Astrodyne TDI
Beam steering is any method that controls the direction of a beam, whether particle, optical, or any other kind. This process makes it possible to achieve ...
[8]
What is Beam Steering? How Phased Arrays Control Microwave and ...
Jun 26, 2025 · This technique enables the precise manipulation of beams without physically moving the antenna or laser source, thus enhancing efficiency and ...
[9]
What are phased array antennas, and how do they work?
Oct 14, 2025 · Phased array antennas are advanced antenna systems that utilize the principle of constructive and destructive interference to steer a beam ...
[10]
Phased Array Antennas: Principles, Advantages, and Types
Beam Steering—the elimination of mechanical repositioning makes the beam steering or beam positioning flexible. The beam steering is established using ...
[11]
Phased Array Antenna Patterns—Part 1 - Analog Devices
Beamwidth provides a metric of angular resolution for antennas. Most commonly, beamwidth is defined by either the half-power beamwidth (HPBW) or the null-to- ...
[12]
Beamwidths and Sidelobe Levels - Antenna Theory
The sidelobe level is the maximum value of the sidelobes (away from the main beam). From Figure 2, the Sidelobe Level (SLL) is -14.5 dB.Missing: steering | Show results with:steering
[13]
Metamaterial Huygens' Surfaces: Tailoring Wave Fronts with ...
These reflectionless surfaces, referred to as metamaterial Huygens' surfaces, provide new beam shaping, steering, and focusing capabilities.
[14]
Huygens principle showing the wavefront reconstruction of a normal...
(a) Beam steering device: the required phase profile is linear, and can be directly determined by the Generalized Snell's law [2].
[15]
https://vtechworks.lib.vt.edu/bitstream/handle/10919/27291/ch3.pdf
[16]
https://www.satnow.com/community/what-are-the-different-types-of-antenna-mechanisms
[17]
Microwaves101 | Phased Array Antennas - Microwave Encyclopedia
Beam Steering: The direction of the peak sensitivity collective antenna can be altered without mechanically re-positioning the individual antennas. For an array ...
[18]
Phased Array Antenna Patterns—Part 2: Grating Lobes and Beam ...
If the beam is steered completely to the horizon, then θ = ±90°, and an element spacing of λ/2 is required (if no grating lobes are allowed in the visible ...
[19]
[PDF] chapter 3 antenna arrays and beamforming - VTechWorks
Array factor of 8-element phase-scanned linear array computed for three frequencies (f0, 1.5f0, and 2f0), with d=0.37λ at f0, designed to steer the beam to ...
[20]
What are the Different Types of Antenna Mechanisms? - SatNow
The gimbal mechanism consists of two orthogonal rotational axes that allow the antenna to be pointed in any direction within a certain range of motion.
[21]
Detail of the elevation RF-rotary joint (simplified) - ResearchGate
It co-rotates with the RF- entrance, the antenna and the mounting platform and allows the relative motion in the elevation axis.
[22]
Servo Drives for Radar Antennas - ingenia
Ingenia's servo drives are optimized for high-speed broadband antennas & radar turntables. In these applications, the rugged communication protocols and the ...
[23]
Beam Steering Technology: Revolutionizing Signal Transmission
Apr 16, 2025 · Beam steering technology enables precise directional control of laser or RF beams in advanced communication and sensing systems.Missing: authoritative | Show results with:authoritative
[24]
[PDF] Flat-Panel Mechanical Beam Steerable Array Antennas With In ...
Jun 7, 2021 · GSAs use a mechanism to physically tilt the antenna in 3D, with or without additional electronic steering, so are low power but bulky. MSAs use ...Missing: mirrors | Show results with:mirrors
[25]
Radar during World War II - Engineering and Technology History Wiki
Radar, which is essentially “seeing” with radio waves, found dozens of other uses in the war. It was used to aim searchlights, then to aim anti-aircraft guns.Missing: gimbals | Show results with:gimbals
[26]
The U.S. Navy: Shipboard Radars - December 1978 Vol. 104/12/910
Most of the Navy's destroyers and frigates built since the mid-1950s have the Mk-68 GFCS with the SPG-53 radar for directing their 5-inch guns. The newest radar ...
[27]
[PDF] CASE FILE COPY - NASA Technical Reports Server (NTRS)
Phased array radar antennas present the advantage^over conventional antennas, of rapid beam steering, this being achieved by varying the relative phases of the ...
[28]
[PDF] Array Phase Shifters: Theory and Technology
Slow wave phase shifters are, in principle, time delay devices (in other words, phase shift is proportional to frequency). Ferroelectric Varactor. One type of ...
[29]
Phased array fundamentals | IET Conference Publication | IEEE Xplore
Phased arrays are a major class of antennas which offer many important features such as electronic beam scanning. Their flexibility has to be assessed ...
[30]
What is a Phased Array Antenna? - Ansys
Jul 8, 2025 · Passive electronically scanned array (PESA): A passive phased array is an antenna with a single transceiver for the entire array. · Active ...Radio Wave Amplitude, Phase... · Phased Array Antenna... · Phased Array Topology
[31]
Active vs. Passive Phased Array Antennas - RF Wireless World
Active phased arrays offer greater flexibility, higher power output, and independent control of each element, they are more complex and expensive.
[32]
Dense Delta-Sigma Phased Arrays | IEEE Journals & Magazine
Jan 21, 2013 · The high cost of high-resolution phase shifters required to maintain precise control over the array beam pattern in traditional phased ...
[33]
Mutual Coupling in Phased Arrays: A Review - Singh - 2013
Apr 22, 2013 · This paper presents a comprehensive review of the methods that model and mitigate the mutual coupling effect for different types of arrays.Parameters Affected due to... · Optimization Techniques for... · Conformal Array
[34]
spotlight mode - Radartutorial.eu
Spotlight-SAR obtains high-resolution by steering the radar beam to keep a target within the beam longer, forming a longer synthetic aperture.
[35]
Research Tools:Phased Array Radar
Electronic Steering As a result, the radar beam can be steered electronically, giving users the ability to control how, when and where the radar scans. This ...
[36]
SABR (Scalable Agile Beam Radar) APG-83 AESA
With SABR, operators can better detect, track, identify and engage a greater number of targets faster, more accurately and at longer ranges compared to ...
[37]
Massive MIMO and Beamforming: The Signal Processing Behind the ...
Massive MIMO uses many antennas to communicate with multiple users, while beamforming adapts antenna radiation patterns. Massive MIMO is a form of beamforming.
[38]
Millimeter Waves May Be the Future of 5G Phones - IEEE Spectrum
Jun 13, 2013 · Samsung's millimeter-wave transceiver technology could enable ultrafast mobile broadband by 2020.
[39]
Orbital angular momentum of light for communications - AIP Publishing
Oct 27, 2021 · Multiplexing: The total data capacity could be potentially increased by multiplexing multiple OAM beams, each carrying an independent data ...INTRODUCTION · OAM multiplexing and... · THz links using OAM...
[40]
MIMO Beamforming, Spatial Multiplexing & Diversity - Remcom
The objective of beamforming is to use multiple antennas to form beams, increasing the SINR, and thereby the throughput, to a receiver. Wireless InSite ...
[41]
[PDF] A draft report on Issues and challenges for polarimetric ...
This report is about technical issues concerning agile-beam phased array radars for weather observation. Specifically we draw parallels with the performance ...
[42]
[PDF] Review of the Evolution of Phased-Array Radar
In the 1960s, the Advanced Research Projects Agency (ARPA) began the world's first technology development programme for a passive phased-array radar, which ...
[43]
Gate tunable graphene-integrated metasurface modulator for mid ...
This enables dynamic beam steering using the applied gate voltage. At normal incidence, and with the gate voltage Vg = VCNP, light will be reflected back at the ...
[44]
Graphene-based active metasurface with more than 330° phase ...
Sufficient phase tunability of metasurfaces has significant potential for dynamic beam steering, hologram and flat optics exhibiting tunable focusing. Here ...
[45]
Dynamic Beam Switching by Liquid Crystal Tunable Dielectric ...
Feb 8, 2018 · Here we experimentally demonstrate the dynamic switching of beam deflection by a silicon-nanodisk dielectric metasurface infiltrated with liquid crystals.
[46]
Wide Field-of-view and Broadband Terahertz Beam Steering Based ...
Jan 30, 2017 · We propose and demonstrate a conceptually new approach for terahertz beam steering by virtue of gap plasmon geodesic antennas.
[47]
Innovations in metamaterial and metasurface antenna design
Metamaterials and metasurfaces have revolutionized antenna design by enabling unprecedented control over electromagnetic waves.
[48]
Broadband electromagnetic cloaking with smart metamaterials
Nov 20, 2012 · Here we demonstrate smart metamaterial cloaking, wherein the metamaterial device not only transforms electromagnetic fields to make an object invisible.
[49]
Enhancing CubeSat Communication Through Beam-Steering ...
However, challenges such as lossy materials, fabrication complexity, and limited bandwidth must be addressed. Their potential in CubeSat communications lies ...
[50]
Additively manufactured metasurfaces and metamaterials: Designs ...
Apr 16, 2025 · Ensuring batch processing and uniformity across large substrates creates problems in scaling up and cost-effectively manufacturing metasurfaces ...
[51]
Active Inference for Closed-loop transmit beamsteering in Fetal ...
Oct 7, 2024 · The proposed cognitive ultrasound system leverages a sequential Monte Carlo method to infer the fetal heart position from the power Doppler signal.