scholarly journals Performance Enhancement of Reconfigurable Metamaterial Reflector Antenna by Decreasing the Absorption of the Reflected Beam

2021 ◽  
Vol 11 (19) ◽  
pp. 8999
Author(s):  
Efi Rahamim ◽  
David Rotshild ◽  
Amir Abramovich
Keyword(s):  
Performance Enhancement ◽  
Dynamic Range ◽  
Beam Steering ◽  
Reflector Antenna ◽  
Sidelobe Level ◽  
Steering Angle ◽  
Varactor Diodes ◽  
Unit Cells ◽  
Simulation Results ◽  
Configuration Simulation

In this study, a new concept for a Ka-band 5G communication tunable reflector metasurface (MS) for beam steering at 28 GHz is proposed. Varactor diodes are used as the tunability component of each unit cell of this MS. Significant improvements in beam steering and bandwidth performance were achieved using this new concept referred to as the stripes configuration. Several different geometries of unit cells arranged in stripes were designed to achieve better performance in directionality, gain, sidelobe level (SLL), and bandwidth in the stripes configuration. Simulation results for a three-stripe MS with different unit cells in each stripe showed better performance in the phase dynamic range and reduced reflectance losses compared to a typical one-stripe MS. The simulation results showed a significant improvement of 3 dB, depending on the steering angle in reflectance gain, compared to a uniform MS (one stripe). Furthermore, a significant improvement of approximately 50% in the accuracy of the steering angle for different operating frequencies was demonstrated. Manufacturing considerations are discussed in this study.

Low-Cost Transmitarray Antenna Designs in V-Band based on Unit-Cells with 1 Bit Phase Resolution

Frequenz ◽  
2019 ◽  
Vol 73 (11-12) ◽  
pp. 355-366
Author(s):  
Martin Frank ◽  
Benedict Scheiner ◽  
Fabian Lurz ◽  
Robert Weigel ◽  
Alexander Koelpin
Keyword(s):  
Low Cost ◽  
Beam Steering ◽  
Experimental Characterization ◽  
Frequency Range ◽  
Steering Angle ◽  
V Band ◽  
Unit Cells ◽  
Linearly Polarized ◽  
Phase Resolution

Abstract This paper presents the design and characterization of linearly polarized low-cost transmitarray antennas with ± 70° azimuth beamforming range in V-band in order to add beam steering functionality to existing radar front ends. The transmitarray antennas are composed of 13 × 13 planar unit-cells. The unit-cells consist of two layers of RO4350B laminate and provide a one bit phase resolution. The desired unit-cell behavior has been validated by simulations and measurements. Eight transmitarrays with different phase distributions have been designed and fabricated to realize different beam steering angles in azimuth. The experimental characterization of the radiation patterns shows the desired performance in the frequency range from 59 GHz to 63 GHz. Additionally, steering angle combinations in azimuth and elevation up to 40° have been realized and successfully demonstrate by measuring the 2D radiation pattern.

One-dimensional beam-steering Fabry–Perot cavity (FPC) antenna with a reconfigurable superstrate

2019 ◽  
Vol 12 (3) ◽  
pp. 233-239
Author(s):  
Lu-Yang Ji ◽  
Shuai Fu ◽  
Lin-Xi Zhang ◽  
Jian-Ying Li
Keyword(s):  
Patch Antenna ◽  
Beam Steering ◽  
Ground Plane ◽  
Steering Angle ◽  
One Dimensional ◽  
Active Elements ◽  
Gain Variation ◽  
Fabry Perot ◽  
Unit Cells ◽  
Good Agreement

AbstractIn this work, a new reconfigurable discrete 1D beam-steering Fabry–Perot cavity antenna with enhanced radiation performance is presented. It consists of a probe-fed patch antenna printed on the ground plane and a reconfigurable metasurface acting as the upper partially reflective surface to realize beam steering. By utilizing 6 × 6 proposed reconfigurable unit cells on the superstrate, the beam-steering angle can be effectively enhanced from ±7° to ±17° with fewer active elements and a much simpler biasing network. The proposed antenna was fabricated to validate the feasibility. Good agreement between the simulated and measured results is achieved. Moreover, the measured realized gains are over 11 dBi with a gain variation from the boresight direction to the tilted direction <0.2 dBi.

scholarly journals Phase-only transmissive spatial light modulator based on tunable dielectric metasurface

Science ◽  
2019 ◽  
Vol 364 (6445) ◽  
pp. 1087-1090 ◽  
Author(s):  
Shi-Qiang Li ◽  
Xuewu Xu ◽  
Rasna Maruthiyodan Veetil ◽  
Vytautas Valuckas ◽  
Ramón Paniagua-Domínguez ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Light Modulator ◽  
Deflection Angle ◽  
Beam Steering ◽  
Beam Deflection ◽  
Spatial Light Modulators ◽  
Light Modulator ◽  
Steering Angle ◽  
Holographic Display ◽  
Light Modulators

Rapidly developing augmented reality, solid-state light detection and ranging (LIDAR), and holographic display technologies require spatial light modulators (SLMs) with high resolution and viewing angle to satisfy increasing customer demands. Performance of currently available SLMs is limited by their large pixel sizes on the order of several micrometers. Here, we propose a concept of tunable dielectric metasurfaces modulated by liquid crystal, which can provide abrupt phase change, thus enabling pixel-size miniaturization. We present a metasurface-based transmissive SLM, configured to generate active beam steering with >35% efficiency and a large beam deflection angle of 11°. The high resolution and steering angle obtained provide opportunities to develop the next generation of LIDAR and display technologies.

Study of Rider Model for Motorcycle Racing Simulation

2020 ◽  
Author(s):  
Masatsugu Nishimura ◽  
Yoshitaka Tezuka ◽  
Enrico Picotti ◽  
Mattia Bruschetta ◽  
Francesco Ambrogi ◽  
...  
Keyword(s):  
Predictive Control ◽  
Running Speed ◽  
Steering Angle ◽  
Conventional Model ◽  
Linear Region ◽  
New Model ◽  
Constant Radius ◽  
Simulation Results ◽  
Braking Force ◽  
Motorcycle Dynamics

Various rider models have been proposed that provide control inputs for the simulation of motorcycle dynamics. However, those models are mostly used to simulate production motorcycles, so they assume that all motions are in the linear region such as those in a constant radius turn. As such, their performance is insufficient for simulating racing motorcycles that experience quick acceleration and braking. Therefore, this study proposes a new rider model for racing simulation that incorporates Nonlinear Model Predictive Control. In developing this model, it was built on the premise that it can cope with running conditions that lose contact with the front wheels or rear wheels so-called "endo" and "wheelie", which often occur during running with large acceleration or deceleration assuming a race. For the control inputs to the vehicle, we incorporated the lateral shift of the rider's center of gravity in addition to the normally used inputs such as the steering angle, throttle position, and braking force. We compared the performance of the new model with that of the conventional model under constant radius cornering and straight braking, as well as complex braking and acceleration in a single (hairpin) corner that represented a racing run. The results showed that the new rider model outperformed the conventional model, especially in the wider range of running speed usable for a simulation. In addition, we compared the simulation results for complex braking and acceleration in a single hairpin corner produced by the new model with data from an actual race and verified that the new model was able to accurately simulate the run of actual MotoGP riders.

Modeling the Microwave Transmissivity of Row Crops

2021 ◽  
Vol 36 (6) ◽  
pp. 816-823
Author(s):  
Jeil Park ◽  
Praveen Gurrala ◽  
Brian Hornbuckle ◽  
Jiming Song
Keyword(s):  
Soil Moisture ◽  
Analytical Solutions ◽  
Periodic Boundary ◽  
Periodic Boundary Conditions ◽  
Measured Data ◽  
Row Crops ◽  
Satellite Retrieval ◽  
Unit Cells ◽  
Simulation Results ◽  
Agricultural Regions

We develop a method to model the microwave transmissivity of row crops that explicitly accounts for their periodic nature as well as multiple scattering. We hypothesize that this method could eventually be used to improve satellite retrieval of soil moisture and vegetation optical depth in agricultural regions. The method is characterized by unit cells terminated by periodic boundary conditions and Floquet port excitations solved using commercial software. Individual plants are represented by vertically oriented dielectric cylinders. We calculate canopy transmissivity, reflectivity, and loss in terms of S-parameters. We validate the model with analytical solutions and illustrate the effect of canopy scattering. Our simulation results are consistent with both simulated and measured data published in the literature.

scholarly journals Dynamic Range Analysis of the Phase Generated Carrier Demodulation Technique

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
M. J. Plotnikov ◽  
A. V. Kulikov ◽  
V. E. Strigalev ◽  
I. K. Meshkovsky
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Range ◽  
Range Analysis ◽  
Upper Limit ◽  
Low Pass ◽  
Nonlinear Character ◽  
Simulation Results ◽  
Low Pass Filters ◽  
First Time ◽  
Phase Generated Carrier

The dependence of the dynamic range of the phase generated carrier (PGC) technique on low-pass filters passbands is investigated using a simulation model. A nonlinear character of this dependence, which could lead to dynamic range limitations or measurement uncertainty, is presented for the first time. A detailed theoretical analysis is provided to verify the simulation results and these results are consistent with performed calculations. The method for the calculation of low-pass filters passbands according to the required dynamic range upper limit is proposed.

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.

High Dynamic Range Colocated Sensoriactuator for Control of High-Speed Optical Systems

2001 ◽  
Author(s):  
Gareth Knowles ◽  
Bruce Bower
Keyword(s):  
High Speed ◽  
Dynamic Range ◽  
Beam Steering ◽  
High Dynamic Range ◽  
Optical Systems ◽  
The Novel ◽  
Actuation Mechanism ◽  
Vibratory Load ◽  
Transmission Reduction ◽  
High Bandwidth

Abstract Vibratory load transmission reduction for precision space A major challenge to the aerospace industry is to develop precision beam steering optics with clear aperture as large as 8 inches that operate at bandwidths of 1KHz, have throws of 3–10 mrad, and position accuracy of 100 nrad. The proposed technology promises to meet these requirements by introducing a new piezoelectronically driven colocated sensoriactuation system. The novel sensor promises to enable ultra-linear, 1nm resolution and 4 KHz small signal bandwidth in a small package. The sensor is integrated into the actuation mechanism in order to provide advantageous colocated functioning. The actuation mechanism is of unique high stiffness and shear strength capable of driving at high-bandwidth with no low coupling modes present. The proposed technology offers a lower cost, lighter weight, lower volume solution that can markedly increase performance capability. The approach is applied to the problem of controlling fast optics for precision optical compensation or hyperspectral imaging. The paper presents aspects of design experiment and system measurement.

scholarly journals Spatiotemporal light control with frequency-gradient metasurfaces

Science ◽  
2019 ◽  
Vol 365 (6451) ◽  
pp. 374-377 ◽  
Author(s):  
Amr M. Shaltout ◽  
Konstantinos G. Lagoudakis ◽  
Jorik van de Groep ◽  
Soo Jin Kim ◽  
Jelena Vučković ◽  
...  
Keyword(s):  
Frequency Comb ◽  
Beam Steering ◽  
Three Dimensional ◽  
Optical Control ◽  
Steering Angle ◽  
Experimental Realization ◽  
Phase Gradient ◽  
Power Efficient ◽  
On Chip ◽  
Frequency Gradient

The capability of on-chip wavefront modulation has the potential to revolutionize many optical device technologies. However, the realization of power-efficient phase-gradient metasurfaces that offer full-phase modulation (0 to 2π) and high operation speeds remains elusive. We present an approach to continuously steer light that is based on creating a virtual frequency-gradient metasurface by combining a passive metasurface with an advanced frequency-comb source. Spatiotemporal redirection of light naturally occurs as optical phase-fronts reorient at a speed controlled by the frequency gradient across the virtual metasurface. An experimental realization of laser beam steering with a continuously changing steering angle is demonstrated with a single metasurface over an angle of 25° in just 8 picoseconds. This work can support integrated-on-chip solutions for spatiotemporal optical control, directly affecting emerging applications such as solid-state light detection and ranging (LIDAR), three-dimensional imaging, and augmented or virtual systems.

The Design and Simulation of a New Z-Axis Resonant Micro-Accelerometer Based on Electrostatic Stiffness

2013 ◽  
Vol 744 ◽  
pp. 478-483
Author(s):  
Bo Yang ◽  
Bo Dai ◽  
Hui Zhao
Keyword(s):  
Dynamic Range ◽  
System Simulation ◽  
High Sensitivity ◽  
Scale Factor ◽  
Effective Frequency ◽  
Large Dynamic Range ◽  
Digital Output ◽  
Structure Simulation ◽  
Simulation Results ◽  
Micro Accelerometer

Resonant micro-accelerometers have good properties such as the large dynamic range, the high sensitivity, the strong anti-interference ability as well as the direct digital output. A new z-axis resonant micro-accelerometer based on electrostatic stiffness is researched. The new z-axis resonant micro-accelerometer consists of a torsional accelerometer and two plane resonators. The sensing movement of the accelerometer is decoupled with oscillation of the plane resonators by electrostatic stiffness, which will benefit to improve the performance of the new z-axis resonant micro-accelerometer. The new structure is designed. The sensitive theory of the acceleration is investigated and the equation of scale factor is deduced under ideal conditions. The simulation is implemented to verify the basic principle by the Ansys and Matlab. The structure simulation results prove that the effective frequency of the torsional accelerometer and the resonator are 0.66kHz and 13.3kHz separately. And the interference modes are isolated with the effective mode apparently. The system simulation results indicate that the scale factor is 37Hz/g and the system has excellent capabilities in locking and tracking natural frequency of resonators, which proves that the basic theory is feasible.

Sign in / Sign up

Export Citation Format

Share Document