scholarly journals Innovative Reconfigurable Metasurface 2-D Beam-Steerable Reflector for 5G Wireless Communication

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1191
Author(s):  
David Rotshild ◽  
Efraim Rahamim ◽  
Amir Abramovich
Keyword(s):  
Beam Steering ◽  
Unit Cell ◽  
Reflection Phase ◽  
Low Profile ◽  
Unit Cells ◽  
Phase Range ◽  
New Type ◽  
Dc Bias ◽  
Communication Methods ◽  
Indoor And Outdoor

A tunable reflector component based on metasurface (MS) with a low profile and reduced mass is offered for indoor and outdoor 5G communication methods to overcome obstacles such as buildings, walls, and turns, and to allow wireless quasi-line of sight path communication at 37 GHz. Integrating varactors with MS unit cells allows tunability and reconfigurability. This approach was presented in many studies, with frequencies of up to K–band. However, today, higher frequencies are used, especially in communication. This work presents the design of a reconfigurable MS reflector, at Ka-band frequencies, based on a new type of resonant unit cell, with uniformed reflection for wide-incident-angular-range, and a simple stimulating DC bias for each MS unit cell, which allows a two–dimensional (2-D) continuous reflection phase manipulation. The unit cell provides a dynamic reflection phase range of over 300° at a wide bandwidth. Simulations of one-dimensional (1-D) and (2-D) at 37 GHz are presented. A steering range of up to ±48° was obtained for azimuth or elevation. A simultaneous independent 2-D beam steering range of up to ±10° in azimuth and up to ± 5° in elevation, allowing obstacles to overcome covering at a practical angular spatial cone of 20° and 10°, is presented.

scholarly journals X-band Band-pass Frequency Selective Surface for Radome Applications

2015 ◽  
Vol 16 (2) ◽  
pp. 281
Author(s):  
Tariq Rahim ◽  
Jiodong Xu
Keyword(s):  
Frequency Selective Surface ◽  
Unit Cell ◽  
Dielectric Substrates ◽  
Low Profile ◽  
X Band ◽  
Analysis And Synthesis ◽  
Unit Cells ◽  
Band Pass ◽  
Frequency Selective ◽  
Unit Cell Dimensions

A low profile multi layer miniaturized unit cell frequency selective surface (FSS) with second-order band-pass response is design. The metallic layers in the form of capacitive patches and inductive grids are separated by dielectric substrates. The non-resonant sub-wavelength unit cells with unit cell dimensions and periodicities on the order of 0.15λ. The overall thickness of approximately 0.03λ is designed which is useful at lower frequencies with long wavelengths. The FSS exhibit a stable frequency response to different angles of incidence and polarizations. The analysis and synthesis of the FSS is done using equivalent circuit method and simulated using CST microwave studio at X-band.

scholarly journals Experimental Characterization of 2 × 2 Electronically Reconfigurable 1 Bit Unit Cells for a Beamforming Transmitarray at X Band

2021 ◽  
Vol 21 (2) ◽  
pp. 153-160
Author(s):  
Biswarup Rana ◽  
In-Gon Lee ◽  
Ic-Pyo Hong
Keyword(s):  
Phase Shifter ◽  
Unit Cell ◽  
Experimental Characterization ◽  
Waveguide Transition ◽  
Transmitted Waves ◽  
X Band ◽  
Unit Cells ◽  
New Type ◽  
Good Agreement

This paper proposes a reconfigurable unit cell for a transmitarray operating at the X band. The unit cell consists of an active patch, a passive patch, and a phase shifter. The active patch has two PIN diodes that change the phase of 180° of the transmitted waves. The passive and active patches both have circular slots to enhance the bandwidth of the transmitted wave. We also propose a new type of experimental characterization technique to measure the performance of the unit cells at the X band without fabricating the entire transmitarray. Instead of a 1 unit cell as described in the literature, we propose 2 × 2 unit cells to measure the performance of unit cells using the X band waveguide. The waveguide consists of a WR-90 section and a rectangular to square waveguide transition section that can be fit to our proposed structure. A good agreement between simulated and measured results was found.

scholarly journals Ultra-Wideband Reconfigurable X-Band and Ku-Band Metasurface Beam-Steerable Reflector for Satellite Communications

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2165
Author(s):  
David Rotshild ◽  
Amir Abramovich
Keyword(s):  
Beam Steering ◽  
Satellite Communications ◽  
Unit Cell ◽  
Ultra Wideband ◽  
Design Parameters ◽  
Continuous Control ◽  
Reflection Phase ◽  
X Band ◽  
Phase Reflection ◽  
Ku Band

A continuously reconfigurable metasurface reflector based on unit cell mushroom geometry that was integrated with a varactor diode is presented in this paper. The unit cell of the metasurface was designed and optimized to operate in the X-band and Ku-band, improving satellite communication’s quality of service. The losses mechanisms of continuous control over the unit cell phase reflection in beam steering resolution are considered and the analysis results are presented. The unit cell design parameters were analyzed with an emphasis on losses and dynamic reflection phase range. The unit cell magnitude and phase reflection are shown in the wide frequency bandwidth and showed a good agreement between all the measurements and the simulations. This metasurface enabled a high dynamic range in the unit cell resonant frequency range from 7.8 to 15 GHz. In addition, the reflection phase and absorption calibration are demonstrated for multiple operating frequencies, namely, 11 GHz, 12 GHz, and 13.5 GHz. Furthermore, design trade-offs and manufacturing limitations were considered. Finally, a beam-steering simulation using the designed metasurface is shown and discussed.

scholarly journals Novel silicon bipodal cylinders with controlled resonances and their use as beam steering metasurfaces

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Samar M. Fawzy ◽  
Ahmed M. Mahmoud ◽  
Yehea I. Ismail ◽  
Nageh K. Allam
Keyword(s):  
Electromagnetic Wave ◽  
High Performance ◽  
Beam Steering ◽  
Unit Cell ◽  
Geometrical Parameters ◽  
Dipole Mode ◽  
Phase Gradient ◽  
Cell Building ◽  
Phase Range ◽  
Wavefront Shaping

AbstractMetasurfaces have paved the way for high performance wavefront shaping and beam steering applications. Phase-gradient metasurfaces (PGM) are of high importance owing to the powerful and relatively systematic tool they offer for manipulating electromagnetic wave fronts and achieving various functionalities. Herein, we numerically present a novel unit cell known as bipodal cylinders (BPC), made of Silicon (Si) and placed on a Silicon dioxide (SiO2) substrate to be compatible with CMOS fabrication techniques and to avoid field leakage into a high index substrate. Owing to its geometrical structure, the BPC structure provides a promising unit cell for electromagnetic wave manipulation. We show that BPC offers a way to shift the electric dipole mode to a frequency higher than that of the magnetic dipole mode. We investigate the effect of varying different geometrical parameters on the performance of such unit cell. Building on that, a metasurface is then presented that can achieve efficient electromagnetic beam steering with high transmission of 0.84 and steering angle of 15.2°; with very good agreement with the theoretically predicted angle covering the whole phase range from 0 to 2$$\pi$$ π .

A New Type of Dislocation Reaction in the Ni2Alti Heusler Phase

1976 ◽  
Vol 34 ◽  
pp. 598-599
Author(s):  
Wen-Shian Tzeng ◽  
P. R. Strutt
Keyword(s):  
Fault Plane ◽  
Unit Cell ◽  
The Other ◽  
Burgers Vector ◽  
Dislocation Pair ◽  
Cscl Type ◽  
Dislocation Reaction ◽  
Structure Phase ◽  
Unit Cells ◽  
New Type

The operative high temperature glide modes in Ni2AlTi have been studied and previously reported (1). The unit cell for this Heusler type structure phase is composed of eight CsCl type unit cells in which Ni atoms form one sublattice while Al and Ti atoms occupy ordered sites on the other sublattice. Electron microscope contrast analyses of dislocations in Ni2AlTi deformed in creep at 1000°C showed the predominant Burgers vector to be ao/2 <110>, where ao refers to the ao/2<110> Heusler unit cell. However, another type of dislocation was observed, this consisted of a pair of ao/2<110> dislocations coupled by a sublattice A.P.B. fault. Subsequent to this, dislocation pairs in the glide configuration have been observed, i.e. the dislocation Burgers vector lies in the fault plane. In what follows an example of such a dislocation pair and its interaction with ao/2<110> dislocations is presented.

Reflectarray Resonant Element based on a Dielectric Resonator Antenna for 5G Applications

2021 ◽  
Vol 36 (7) ◽  
pp. 844-851
Author(s):  
Nur Sallehuddin ◽  
Mohd Jamaluddin ◽  
Muhammad Kamarudin ◽  
Muhammad Dahri
Keyword(s):  
Reflection Loss ◽  
Dielectric Resonator ◽  
Phase Shifter ◽  
High Gain ◽  
Unit Cell ◽  
Dielectric Resonator Antenna ◽  
Microstrip Patch ◽  
Reflection Phase ◽  
Phase Range ◽  
High Reflection

The performance of a proposed cross hybrid dielectric resonator antenna (DRA) element for dual polarization configuration operating at 26 GHz for 5G applications is presented in this paper. The new cross hybrid DRA unit cell is introduced which combines a cross shape DRA with a bottom loading cross microstrip patch. This technique of a bottom loading cross microstrip patch is chosen as the tuning mechanism (varying the length of the microstrip to tune the phase) instead of changing the DRA dimensions because of their ease of implementation and fabrication. By doing so, high reflection phase range with low reflection loss performance can be obtained, which is essential for a high bandwidth and high gain reflectarray for 5G applications. The design and simulation have been done using commercial software of CST MWS. The reflection loss, reflection phase and slope variation were analyzed and compared. A metallic cross microstrip patch of varying length placed beneath the DRA to act as the phase shifter to tune the phase and give smooth variation in slope with a large phase range. The proposed cross hybrid DRA unit cell provides a high reflection phase range of 342º and 1.8 dB reflection loss. The computed results are compared with experimental results revealing reasonable agreement, thereby confirming the viability of the design.

scholarly journals Demonstration of > 2π reflection phase range in optical metasurfaces based on detuned gap-surface plasmon resonators

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Christopher Damgaard-Carstensen ◽  
Fei Ding ◽  
Chao Meng ◽  
Sergey I. Bozhevolnyi
Keyword(s):  
Surface Plasmon ◽  
Beam Steering ◽  
Phase Variation ◽  
Proof Of Concept ◽  
Size Dependent ◽  
Reflection Phase ◽  
Arbitrary Phase ◽  
Linearly Polarized ◽  
Phase Range ◽  
Extended Reflection

Abstract Plasmonic metasurfaces, representing arrays of gap-surface plasmon (GSP) resonators and consisting of arrays of metal nanobricks atop thin dielectric layers supported by thick metal films, constitute an important subclass of optical metasurfaces operating in reflection and enabling the realization of numerous, diverse and multiple, functionalities. The available phase variation range is however limited to being $$<\! 2\pi$$ < 2 π , a circumstance that complicates the metasurface design for functionalities requiring slowly varying phases over the whole range of $$2\pi$$ 2 π , e.g., in holographic applications. The available phase range also determines the wavelength bandwidth of metasurfaces operating with linearly polarized fields due to the propagation (size-dependent) nature of the reflection phase. We suggest an approach to extend the phase range and bandwidth limitations in the GSP-based metasurfaces by incorporating a pair of detuned GSP resonators into a metasurface elementary unit cell. With detailed simulations related to those for conventional single-resonator metasurfaces and proof-of-concept experiments, we demonstrate that the detuned-resonator GSP metasurfaces designed for beam steering at $${900}\,\,\hbox {nm}$$ 900 nm wavelength exhibit the extended reflection phase and operation bandwidth. We believe that the considered detuned-resonator GSP metasurfaces can advantageously be exploited in applications requiring the design of arbitrary phase gradients and/or broadband operation with linearly polarized fields.

Bayesian removal of noise for increased sensitivity in vector pattern recognition lattice imaging of interfaces

1993 ◽  
Vol 51 ◽  
pp. 994-995
Author(s):  
L. Fei ◽  
P. Fraundorf
Keyword(s):  
Pattern Recognition ◽  
Perfect Crystal ◽  
Unit Cell ◽  
Ion Milling ◽  
Beam Radiation ◽  
Major Interest ◽  
Unit Cells ◽  
Mapping Process ◽  
Increased Sensitivity ◽  
Electron Microscopes

Interface structure is of major interest in microscopy. With high resolution transmission electron microscopes (TEMs) and scanning probe microscopes, it is possible to reveal structure of interfaces in unit cells, in some cases with atomic resolution. A. Ourmazd et al. proposed quantifying such observations by using vector pattern recognition to map chemical composition changes across the interface in TEM images with unit cell resolution. The sensitivity of the mapping process, however, is limited by the repeatability of unit cell images of perfect crystal, and hence by the amount of delocalized noise, e.g. due to ion milling or beam radiation damage. Bayesian removal of noise, based on statistical inference, can be used to reduce the amount of non-periodic noise in images after acquisition. The basic principle of Bayesian phase-model background subtraction, according to our previous study, is that the optimum (rms error minimizing strategy) Fourier phases of the noise can be obtained provided the amplitudes of the noise is given, while the noise amplitude can often be estimated from the image itself.

scholarly journals Prediction of Effective Thermal Conductivities of Four-Directional Carbon/Carbon Composites by Unit Cells with Different Sizes

2021 ◽  
Vol 11 (3) ◽  
pp. 1171
Author(s):  
Chang Xu ◽  
Zhihong Sun ◽  
Guowei Shao
Keyword(s):  
Carbon Fiber ◽  
Longitudinal Direction ◽  
Unit Cell ◽  
Carbon Composites ◽  
Temperature Boundary ◽  
The Matrix ◽  
Unit Cells ◽  
Experimental Values ◽  
Different Diameters ◽  
Thermal Conductivities

Two-unit cells developed to predict the effective thermal conductivities of four-directional carbon/carbon composites with the finite element method are proposed in this paper. The smaller-size unit cell is formulated from the larger-size unit cell by two 180° rotational transformations. The temperature boundary conditions corresponding to the two-unit cells are derived, and the validity is verified by the temperature and heat flux distributions at specific positions of the larger-size unit cell and the smaller-size unit cell. The thermal conductivities of the carbon fiber bundles and carbon fiber rods are measured firstly. Then, combined with the properties of the matrix, the effective thermal conductivities of the four-directional carbon/carbon composites are numerically predicted. The results in transverse direction predicted by the larger-size unit cell and the smaller-size unit cell are both higher than experimental values, which are 5.8 to 6.2% and 7.3 to 8.2%, respectively. In longitudinal direction, the calculated thermal conductivities of the larger-size unit cell and the smaller-size unit cell are 6.8% and 6.2% higher than the experimental results, respectively. In addition, carbon fiber rods with different diameters are set to clarify the influence on the effective thermal conductivities of the four-directional carbon/carbon composites.

scholarly journals A Low-Profile HF Meandered Dipole Antenna with a Ferrite-Loaded Artificial Magnetic Conductor

2021 ◽  
Vol 11 (5) ◽  
pp. 2237
Author(s):  
Oh Heon Kwon ◽  
Won Bin Park ◽  
Juho Yun ◽  
Hong Jun Lim ◽  
Keum Cheol Hwang
Keyword(s):  
High Frequency ◽  
Dipole Antenna ◽  
Unit Cell ◽  
Operating Frequency ◽  
High Permeability ◽  
Magnetic Conductor ◽  
Artificial Magnetic Conductor ◽  
Low Profile ◽  
Compact Size ◽  
Binary Genetic Algorithm

In this paper, a low-profile HF (high-frequency) meandered dipole antenna with a ferrite-loaded artificial magnetic conductor (AMC) is proposed. To operate in the HF band while retaining a compact size, ferrite with high permeability is applied to the unit cell of the AMC. The operating frequency bandwidth of the designed unit cell of the AMC is 1.89:1 (19–36 MHz). Thereafter, a meandered dipole antenna is designed by implementing a binary genetic algorithm and is combined with the AMC. The overall size of the designed antenna is 0.06×0.06×0.002 λ3 at the lowest operating frequency. The proposed dipole antenna with a ferrite-loaded AMC is fabricated and measured. The measured VSWR bandwidth (<3) covers 20–30 MHz on the HF band. To confirm the performance of the antenna, a reference monopole antenna which operates on the HF band was selected, and the measured receiving power is compared with the result of the proposed antenna with the AMC.

Sign in / Sign up

Export Citation Format

Share Document