Beam Steering Ability Research Articles

Planar Polarization Rotation Pattern Manipulation Surfaces With Enhanced Incident Angle Range and Beam-Steering Ability

Planar Polarization Rotation Pattern Manipulation Surfaces With Enhanced Incident Angle Range and Beam-Steering Ability

A Compact Microwave/Millimeter-wave Shared-aperture Antenna with Wideband Millimeter-wave Beam-steering Ability

A Compact Microwave/Millimeter-wave Shared-aperture Antenna with Wideband Millimeter-wave Beam-steering Ability

A dual-band 3-bit reconfigurable intelligent surface with independent control of phases

Reconfigurable Intelligent Surfaces (RISs) have received a great deal of attention from the wireless communication community due to their powerful ability to improve the wireless communication environment. Dual-band RIS enables aperture to share two bands, improving spectrum utilization in wireless communications and thus expanding communication capacity. However, most of the reported dual-band RISs cannot achieve independent controls of the dual-band phases, which greatly limits their practical application in wireless communications. In this paper, we propose a dual-band 3-bit RIS to achieve independent controls of the reflection phases in two frequency bands by designing two tunable structures without raising the profile. It also exhibits low sensitivity to incident angles between 0� and 50�. Thereafter, the beam steering ability of the proposed RIS is further investigated with experiments under normal and oblique incidences at two frequencies, which demonstrates the powerful potential of RISs to manipulate the electromagnetic wave propagation environment.

High-efficiency ultrathin metasurfaces with simultaneous control of complete phase, amplitude, and polarization.

Metasurfaces that can simultaneously manipulate both amplitude and phase have garnered interest and have promising applications owing to their strong beam-steering ability; however, achieving a high maximum transmission while covering the full phase shift remains challenging. This paper proposes a chiral-structured meta-atom composed of two external cross-polarized patches and an internal coupling structure. It enables the independent modulation of the phase, amplitude, and polarization at large incidence angles and ensures a high maximum transmission with a complete phase shift enabled by the two internal rotation structures. The transmission phase and amplitude can be independently controlled by adjusting the geometry and rotation angle of the meta-atoms. The performance and feasibility of the method were verified using an ultra-thin high-order Bessel beam generator sample with a thickness of 2 mm (about λ0/11 at 14 GHz). This design can meet arbitrary requirements for extreme beam steering and has broad application prospects in the fields of electromagnetism and photonics.

Reconfigurable Bidirectional Beam-Steering Aperture With Transmitarray, Reflectarray, and Transmit-Reflect-Array Modes Switching

The design and experiment of an electronically reconfigurable bidirectional spatially-fed array are presented, which combines the functionalities of reconfigurable transmitarray (TA), reflectarray (RA), and transmit-reflect array (TRA). First, we demonstrate a novel bidirectional unit cell composed of a tunable resonant layer between a pair of orthogonally oriented metal gratings. Two positive-intrinsic-negative (PIN) diodes are integrated into the tunable resonant layer to achieve the 1-bit phase resolution in either transmission or reflection mode. Based on the proposed unit cell, a 16 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times16$ </tex-math></inline-formula> -element array arranged in a square grid, which can be controlled independently by a field programmable gate array (FPGA)-based digital control circuit, is excited by a linearly-polarized horn to show the beam steering ability of reconfigurable TA and RA. To realize TRA function integration with the bidirectional beam independent steering simultaneously, the method based on superposition of the aperture fields (SAF) on the aperture is used. In SAF design, the entire aperture is divided into transmission and reflection modes co-existing, and the arrangement and phase distribution are optimized by particle swarm optimization (PSO) algorithm to achieve minimum sidelobe levels (SLLs) and peak gain of bidirectional beam. The measured results of the prototype demonstrate that the antenna can steer bidirectional beam both in simultaneous and time division operating modes, which is not reported to the best of the authors’ knowledge. Our proposed method opens a new avenue for the design of high-performance multifunctional reconfigurable antenna systems.

Design a Multistub Array Antenna at 28 GHz with Beam Switching Ability

In this paper, a Millimeter Wave antenna is designed which has a compact, lightweight and planar configuration. The frequency band is 27–29.5 GHz as a candidate band for 5G/millimeter Wave (mmW) systems. The antenna structure is similar to Quasi Yagi antenna which has driver, director, feeding part, and reflector. Substrate Integrated Waveguide used for feeding part of single element antenna and Wilkinson power divider used for antenna array feeding network. The proposed antenna has been simulated, fabricated, and measured (S11, E, and H pattern). The simulation and measurement values showed good similarity. The switched line phase shifter used to consider the beam steering (rotation) ability of the designed antenna which is important in (mmW) systems such as RADARs and mobile handsets. To evaluate this ability, for 0 ° , 30 ° , 45 ° , and 90 ° phase differences, the beam steering angle ( θ ) simulated and also for − 90 ° and 90 ° implemented. The results showed that the efficiency, S11, and E patterns in the rotated beam is suitable and without degradation in antenna operation. To simulate and evaluate the designed antenna HFSS and CST Software are used.

1-Bit Wide-Angle Folded Reflectarray Antenna at Ka-Band

This letter presents a folded reflectarray (FRA) capable of electrical beam steering in the Ka-band. The FRA consists of a low-profile feeding source, a dual-layer wire grid, and 36×36 polarization twisting reflective elements. An element of center shorted patch with two plated through holes is proposed where only two switches are required for polarization twisting and 1-bit encoding. A cavity is then introduced surrounding the element to improve the beam-steering performance. To verify the proposed element, two prototypes with 0° and 60° beam directions are designed and experimented where the metal stub and open circuit are used to model “ <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on/off</small> ” states of PIN diodes for simplification. The measured peak gain of 0°FRA is 27.5 dBi with 2 dB gain bandwidth of 28–32 GHz (13.3%). A measured gain drop of 3.25 dB is achieved by the 60°FRA, which verifies the wide-angle beam-steering ability. The measured reflection coefficient of the feeding source is less than −15 dB over the operating band. The proposed FRA has a good potential to realize beam-steering with real PIN diodes for the satellite communications.

Simulation and Observational Evaluation of Space Debris Detection by Sanya Incoherent Scatter Radar

AbstractThe Sanya incoherent scatter radar (SYISR) is a newly built active digital phased array, all solid‐state transmitting and digital receiving incoherent scatter radar in Sanya (18.3°N, 109.6°E). The radar frequency band is from 430 to 450 MHz. The Sanya site is a low latitude station in China dedicated for ionospheric investigation. Meanwhile, SYISR is also suitable for detecting a wide range of space debris because of its high power and flexible beam steering ability. In this paper, we first calculate the detectable lower limit size of space debris with respect to integration time and range based on SYISR parameters through theoretical simulation. Then, we selected several typical space debris, with a size near the theoretical detectable lower limit, to perform the experiment. We found that the estimated radar cross section versus range accorded well with the theoretical curve, which confirmed our simulation. Specifically, the detectable lower limit size of space debris is ∼8 cm in a range of 1,000 km given a threshold signal‐to‐noise ratio of 14 dB. This value decreases to ∼3 cm if a 200‐ms coherent integration is implemented. We further performed several experiments on objects with different inclinations using signals with 0.3 and 4 MHz under both static staring and tracking modes. In comparison with the two‐line element file predicted raw orbit, the tracking error of 0.3 and 4 MHz are 7 km and 400 m, respectively, without coherent integration in the processing. The study expands the function of the SYISR and should be beneficial to our ionospheric data inversion given the frequent occurrence of space debris around the SYISR.

A dual-band reconfigurable intelligent metasurface with beam steering

In recent years, reconfigurable metasurfaces have become research hotspots since they can manipulate electromagnetic waves dynamically and flexibly. The realisation of cost-effective and energy-efficient wireless communications via reconfigurable intelligent surfaces (RISs) is attractive in various application scenerios. In this work, a -polarized dual-band reconfigurable metasurface with beam steering ability is proposed to combat signal attenuation in wireless communications. By varying the bias voltages of the integrated varactors in the specially designed meta-atom, 0 and π phase responses have been excited around both 2.4 and 5.8 GHz. Taking advantage of this unique feature, we proposed a one-bit coding RIS device which provides dual-band application. To validate the proposed concepts, a reconfigurable metasurface composed of 16 × 16 elements was fabricated and measured. The measurement results agree well with the simulation, so the proposed prototype is a promising candidate for future intelligent communications.

A Low-Profile Beam-Steering Reflectarray With Integrated Leaky-Wave Feed and 2-Bit Phase Resolution for Ka-Band SatCom

A novel reflectarray (RA) with ultralow-profile and 2-bit phase quantization beam-steering ability is presented in this article. To reduce the profile, a Leaky-wave feed is used to excite the RA with enhanced illumination efficiency. Moreover, simultaneous sum and difference patterns are also obtained to provide beam flexibility. The entire thickness of the proposed RA is less than 3&#x0025; of that of the conventional front-fed RA with the same aperture. To increase the efficiency of the RA, a novel unit cell consisting of a polarizer layer and a reflection layer is developed, which is configured to provide polarization rotation and 2-bit phase shifts by using a hybrid of tunable polarization and discrete resonator. The operation principle, theoretical explanation, and implementation of the proposed antenna are elaborated in this work. To prove the design concept and beam scanning performance, an array with <inline-formula> <tex-math notation="LaTeX">$9 \times 7$ </tex-math></inline-formula> unit cells operating at Ka-band is designed and simulated first. Two-dimensional beam scanning within the range of &#x00B1;30&#x00B0; has been verified. Then, a passive prototype with <inline-formula> <tex-math notation="LaTeX">$9\,\,\times67$ </tex-math></inline-formula> unit cells is designed, fabricated, and measured. Experimental results show aperture efficiency of 35.1&#x0025; and illumination efficiency of 43.4&#x0025;. The developed RA is scalable, and it provides a viable low-cost solution to develop low-profile, high-gain and beam-steering array antennas for satellite applications.

A Programmable-Metasurface-Based TDMA Fast Beam Switching Communication System at 28 GHz

A programmable metasurface (PM) is a promising active antenna array approach for beamforming purposes. In comparison with a phased array, our interested PM achieves beamforming by electronically control the states of Pin diodes instead of phase shifters, which highly reduces the system price and power consumption. In this letter, a novel wireless communication system with an ultrafast beam steering ability using a PM at 28 GHz in a time-division multiple access (TDMA) scenario is constructed. Realization of the entire system dealing with technical specifications is introduced in detail. System performances with different beam switching times, modulation schemes, and frame structures are analyzed. As a conclusion, we prove that a PM system is a possible candidate for fast beam switching with low cost and complexity.

Numerical simulation research of wide-angle beam steering based on catenary shaped ultrathin metalens

In this paper, a bilayer ultrathin (≈0.153λ) metalens is presented by exploring the advantage of the metasurface with catenary shape and symmetry transformation. The simulation results show that the proposed metalens has high polarization conversion efficiency (>90% even when the incidence angle is 60°), and the wide-angle beam steering ability is beyond ± 70°. Compared with the previous beam steering lens with transmitted array, the metalens in this paper exhibits obvious advantages. Moreover, the longitudinal local catenary fields existing in this metalens can ensure the wide-angle operation for this structure.

Design of Steered Array Lens Antenna System with Isolation Enhancement

A new compact economical patch array antenna with beam steering ability and mutual coupling reduction between the patches is presented in this article. By incorporating modified hexagonal spilt ring resonator metamaterial structure in one of the 1 X 2 patch array enables the property of beam steering as well as mutual coupling reduction. Similarly, by incorporating modified hexagonal split ring metamaterial structure in both the patch of 1x2 patch array antenna mutual coupling reduction of around 21dB at 2.4GHz without beam steering capability is observed. The spacing of 0.25λo between the patches of an antenna array, around 24 dB lower mutual coupling at the operating frequency is obtained. Both left and right modified patch produces a beam scanning of -200 to +200 respectively. The fabricated prototype antenna results are validated with simulation results using experimental measurements.

Beam Steering Conformal Transmitarray Employing Ultra-Thin Triple-Layer Slot Elements

A novel conformal transmitarray with beam steering ability is presented. First, an ultra-thin transmitarray element consisting of three layers of identical square ring slots is developed. The element has a thickness of 0.508 mm (0.04 wavelength in the free space at 25 GHz), achieving a transmission phase range of 330° with a maximum 3.6 dB loss. The element is then applied to a curved transmitarray conformal to a cylindrical surface fed by a standard gain horn with about a 10-dBi gain. A prototype is fabricated radiating a boresight beam with a peak measured gain of 19.6 dBi and an aperture efficiency of 25.1%. Second, when the transmitting surface of the above array is divided into two parts from the middle with different main beam directions, the combined beam can be radiated to an oblique angle with respect to the boresight direction. Using this method, a mechanical beam scanning conformal transmitarray antenna is designed. Its size is about 2.5 times larger than the fixed-beam one and consists of six transmitting surfaces with main beams directed to different angles. By rotating the feed horn to different positions, the main beam of the array can be switched to ±15°, ±10°, ±5°, and 0°. A prototype is fabricated with a stable gain of about 18.7 dBi at all beam angles.

High-reflectivity non-periodic sub-wavelength gratings with small-angle beam-steering ability and its application in Fabry–Perot cavity

We report a high-reflectivity non-periodic sub-wavelength gratings (SWGs) mirror with small-angle beam-steering ability for reflect light. It presents a distinctive characteristic of flexibly controlling the width of oscillation optical field for the improved Fabry–Perot (F–P) cavity. We propose a detailed principle analysis of the improved cavity. By finding out a set of SWGs with the designed structural parameters, both high reflectivity (> 93%) and beam steering (1°) can be implemented. By setting beam-steering angle and cavity length, we can control the width of oscillation optical field in the improved cavity. Beam steering ability and property of controlling the oscillation width are numerically investigated by finite element method. Simulation results prove that cavity length and steering angle can effectively control the main width of oscillation optical field, and the width is linearly associated with the cavity length.

High‐Efficiency and Wide‐Angle Beam Steering Based on Catenary Optical Fields in Ultrathin Metalens

AbstractRecent advances in artificial subwavelength structures promise the realization of ultrathin, lightweight, and flat metalens, providing a potential candidate for traditional bulky and curved lens. Nevertheless, most metalenses are generally suffering from serious off‐axis aberration, resulting in a limited field‐of‐view (FOV). Here, a methodology to extend the FOV of metalens is presented by exploring the local catenary optical fields and symmetry transformation from rotational symmetry to transversal symmetry. As a proof of the concept, a high efficiency (&gt;80% even when the incidence angle is titled by 60°) and ultrathin (≈0.127 λ) metalens consisting of bilayer geometric metasurface is designed, fabricated, and characterized. The wide FOV of metalens benefiting from local catenary fields and symmetry transformation is numerically demonstrated by full‐wave simulation and ray tracing method. Moreover, the wide‐angle beam steering ability beyond ± 60° is experimentally demonstrated, which exhibits obvious advantages compared with previous beam steering transmitarrays. The novelty of the proposed methodology lies at the fact that both transversal and longitudinal local catenary fields are excited in a single component: the transversal catenary field is utilized for high efficiency spin–orbit interaction and phase modulation, while the longitudinal catenary field and symmetry transformation ensure wide‐angle operation.

Highly Directional Steerable Antennas: High-Gain Antennas Supporting User Mobility or Beam Switching for Reconfigurable Backhauling

Modern millimeter-wave (mmWave) communication systems for large indoor areas and most outdoor scenarios require high-gain antennas with beam-steering ability to support user mobility or beam switching for reconfigurable backhauling. In this article, two new concepts for the development of highly directional steerable mmWave antennas are proposed and analyzed. The first one is modular antenna array (MAA) technology, which allows the creation of large-aperture, high-gain adaptive antenna arrays in a cost-effective and scalable manner. Two MAA configurations based on the existing phased subarray module are considered and analyzed for mmWave small-cell access and backhauling. The second prospective technology that fulfills the required antenna parameters for mmWave smallcell flexible backhauling is the lens-array antenna (LAA). The combination of the dielectric lens for aperture increasing with only one subarray module with beam-steering capabilities may provide 25?30-dBi total antenna gain with azimuth sector sweeping !45?.

High-transmittivity non-periodic sub-wavelength high-contrast grating with large-angle beam-steering ability

We present a high-transmittivity non-periodic sub-wavelength high-contrast grating (HCG) with large-angle beam-steering ability for transmitted light. The phase front profile of transmitted light is a decisive factor to the beam-steering property of the HCG. By designing the structural parameters of the HCG, both beam steering and high transmittivity can be achieved. The properties of the beam steering and transmission are numerically studied with the finite element method. The results show that the transmittivity is up to 0.91 and the steering angle is 27.42° which is consistent with the theoretical 30°.

A Novel Beam Steering of Hybrid Switchable Beam Textile Antenna

A novel hybrid switchable beam textile antenna (HSBTA) is proposed in this research. The HSBTA introduced by a coaxial probe technique to feed current flow to center of HSBTA and distribute the current to four circles of radiating elements. This research found that the integration of RF switches and electronic components is successfully embedded into wearable textile antenna using a silver-conductive epoxy adhesive. The four RF switches are then incorporated at four ideal locations of HSBTA's circle radiating elements to generate the beam steering ability with directivity as high as 6.8 dBi. With the help of particular RF switching scheme, the HSBTA has successfully tailored the beam to four different angles of 0°/360°, 90°, 180°, and 270° at single operating frequency of 2.45 GHz. Dimensionwise, 88 × 88 mm2 could lead the HSBTA to be deployed on smart garment for wireless body area network application. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1893–1897, 2013

A FABRICATION OF INTELLIGENT SPIRAL RECONFIGURABLE BEAM FORMING ANTENNA FOR 2.35-2.39 GHZ APPLICATIONS AND PATH LOSS MEASUREMENTS

A reconflgurable beam forming antenna prototype using a spiral feed line is proposed in this paper. The presented antenna is integrated with PIN diode switches at a speciflc location of spiral feed line. It is discovered that the beam steering ability is greatly in∞uenced by the spiral arm feed network. Four PIN diode switches have been incorporated at four difierent arms of spiral feed line to realize a beam forming ability. The intelligence behaviour of this antenna is conferred when the switches are connected to programmable intelligent computer (PIC) microcontroller. Certain conflgurations of PIC allow the antenna's radiation patterns to be adaptively changed within 0.01ms. Therefore, the proposed antenna is capable of electronically forming the beam up to four difierent angles of +176 - , +10 - , i1 - and i12 - . This antenna is small in size with 100mm by 100mm of substrate dimension. In this research, the site fleld antenna performance relying on the received signal strength (RSS) testing is tested intensively in Universiti Malaysia Perlis with varied distant points of line-of- sight (LOS) and non-line-of-sight (NLOS) propagation. With good simulation and measurement results, this antenna could be a promising candidate to be installed in applications such as a smart antenna system, cognitive radio, WiMAX and long term evolution (LTE).