scholarly journals Pure and Linear Frequency Converter Temporal Metasurface

2021 ◽  
Author(s):  
Sajjad Taravati ◽  
George V. Eleftheriades
Keyword(s):  
Frequency Conversion ◽  
Frequency Converter ◽  
Temporal Frequency ◽  
Extraordinary Wave ◽  
Phase Shifters ◽  
Linear Frequency ◽  
Telecommunication Systems ◽  
Digitally Controlled ◽  
Field Programmable ◽  
Invisibility Cloaks

Abstract Metasurfaces are ultrathin structures which are constituted by an array of subwavelength scatterers with designable scattering responses. They have opened up unprecedented exciting opportunities for extraordinary wave engineering processes. On the other hand, frequency converters have drawn wide attention due to their vital applications in telecommunication systems, health care devices, radio astronomy, military radars and biological sensing systems. Here, we show that a spurious-free and linear frequency converter metasurface can be realized by leveraging unique properties of engineered transmissive temporal supercells. Such a metasurface is formed by time-modulated supercells; themselves are composed of temporal and static patch resonators and phase shifters. This represents the first frequency converter metasurface possessing large frequency conversion ratio with controllable frequency bands and transmission magnitude. In contrast to conventional nonlinear mixers, the proposed temporal frequency converter offers a linear response. In addition, by taking advantage of the proposed surface-interconnector-phaser-surface (SIPS) architecture, a spurious-free and linear frequency conversion is achievable, where all undesired mixing products are strongly suppressed. The proposed metasurface may be digitally controlled and programmed through a field programmable gate array. This makes the spurious-free and linear frequency converter metasurface a prominent solution for wireless and satellite telecommunication systems, as well as invisibility cloaks and radars. This study opens a way to realize more complicated and enhanced-efficiency spectrum-changing metasurface.

scholarly journals Programmable nonreciprocal meta-prism

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sajjad Taravati ◽  
George V. Eleftheriades
Keyword(s):  
Three Dimensional ◽  
Frequency Component ◽  
Phase Shifters ◽  
Frequency Dependent ◽  
Spatial Decomposition ◽  
Spatial Frequencies ◽  
Digitally Controlled ◽  
Field Programmable ◽  
Lorentz Reciprocity Theorem ◽  
Spatially Variant

AbstractOptical prisms are made of glass and map temporal frequencies into spatial frequencies by decomposing incident white light into its constituent colors and refract them into different directions. Conventional prisms suffer from their volumetric bulky and heavy structure and their material parameters are dictated by the Lorentz reciprocity theorem. Considering various applications of prisms in wave engineering and their growing applications in the invisible spectrum and antenna applications, there is a demand for compact apparatuses that are capable of providing prism functionality in a reconfigurable manner, with a nonreciprocal/reciprocal response. Here, we propose a nonreciprocal metasurface-based prism constituted of an array of phase- and amplitude-gradient frequency-dependent spatially variant radiating super-cells. In conventional optical prisms, nonreciprocal devices and metamaterials, the spatial decomposition and nonreciprocity functions are fixed and noneditable. Here, we present a programmable metasurface integrated with amplifiers to realize controllable nonreciprocal spatial decomposition, where each frequency component of the incident polychromatic wave can be transmitted under an arbitrary and programmable angle of transmission with a desired transmission gain. Such a polychromatic metasurface prism is constituted of frequency-dependent spatially variant transistor-based phase shifters and amplifiers for the spatial decomposition of the wave components. Interesting features include three-dimensional prism functionality with programmable angles of refraction, power amplification, and directive and diverse radiation beams. Furthermore, the metasurface prism can be digitally controlled via a field- programmable gate array (FPGA), making the metasurface a suitable solution for radars, holography applications, and wireless telecommunication systems.

scholarly journals Programmable Nonreciprocal Meta-Prism

2021 ◽  
Author(s):  
Sajjad Taravati ◽  
George V. Eleftheriadees
Keyword(s):  
Three Dimensional ◽  
Frequency Component ◽  
Phase Shifters ◽  
Frequency Dependent ◽  
Spatial Decomposition ◽  
Spatial Frequencies ◽  
Digitally Controlled ◽  
Field Programmable ◽  
Lorentz Reciprocity Theorem ◽  
Spatially Variant

Abstract Optical prisms are made of glass and map temporal frequencies into spatial frequencies by decomposing incident white light into its constituent colors and refract them into different directions. Conventional prisms suffer from their volumetric bulky and heavy structure and their material parameters are dictated by the Lorentz reciprocity theorem.. Considering various applications of prisms in wave engineering and their growing applications in the invisible spectrum and antenna applications, there is a demand for compact apparatuses that are capable of providing prism functionality in a reconfigurable manner, with a nonreciprocal/reciprocal response. Here, we propose a nonreciprocal metasurface-based prism constituted of an array of phase-and amplitude-gradient frequency-dependent spatially variant radiating super-cells. In conventional optical prisms, nonreciprocal devices and metamaterials, the spatial decomposition and nonreciprocity functions are fixed and noneditable. Here, we present a programmable metasurface integrated with amplifiers to realize controllable nonreciprocal spatial decomposition, where each frequency component of the incident polychromatic wave can be transmitted under an arbitrary and programmable angle of transmission with a desired transmission gain. Such a polychromatic metasurface prism is constituted of frequency-dependent spatially variant transistor-based phase shifters and amplifiers for the spatial decomposition of the wave components. Interesting features include three-dimensional prism functionality with programmable angles of refraction, power amplification, and directive and diverse radiation beams. Furthermore, the metasurface prism can be digitally controlled via a field-programmable gate array (FPGA), making the metasurface a suitable solution for radars, holography applications, and wireless telecommunication systems.

scholarly journals Resonance overvoltage control algorithms in long cable frequency conversion drive based on discrete mathematics

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 408-418
Author(s):  
Yonghong Deng ◽  
Quanzhu Zhang
Keyword(s):  
Mathematical Model ◽  
Control Strategy ◽  
Frequency Conversion ◽  
Balance Control ◽  
Frequency Converter ◽  
Active Power ◽  
Drive System ◽  
Discrete Mathematics ◽  
Power Controller ◽  
Capacitor Voltage

AbstractIn order to solve the problem that the long cable variable voltage and variable frequency (VVVF) system does not adopt an effective capacitor voltage sharing control method, resulting in a poor effect of resonance overvoltage control, the resonance overvoltage control algorithm of the long cable VVVF system based on discrete mathematics is studied. First, the long cable frequency conversion drive system is established. In order to ensure voltage loss in the range of motor requirements, a frequency converter–cable–motor (ICM) system connection mode is used to maintain the system operation. Based on the research of the capacitor voltage balance control strategy of a long cable frequency conversion drive system, the discrete mathematical model of the AC side of the ICM system is established by using this control strategy. The improved constant active power controller is obtained by establishing the mathematical model, and the resonant overvoltage in a long cable frequency conversion drive is realized by using the constant active power controller. The experimental results show that the algorithm can effectively control the resonance overvoltage phenomenon in the long cable frequency control system, and the control accuracy is over 97%. It has good performance and can be applied in practice.

scholarly journals Soliton crystal 50G Hz micro-comb for Q-band microwave frequency conversion

2020 ◽  
Author(s):  
David Moss
Keyword(s):  
High Performance ◽  
Frequency Conversion ◽  
Frequency Converter ◽  
Microwave Frequency ◽  
Local Oscillator ◽  
Rf Power ◽  
Potential Cost ◽  
Frequency Converters ◽  
Spurious Suppression ◽  
Good Agreement

We report a broadband microwave frequency converter based on a coherent Kerr optical micro-comb generated by an integrated micro-ring resonator. The coherent micro-comb displays features that are consistent with soliton crystal dynamics with an FSR of 48.9-GHz. We use this to demonstrate a high-performance millimeter-wave local oscillator at 48.9-GHz in the Q-band for microwave frequency conversion. We experimentally verify the microwave performance up to 40 GHz, achieving a ratio of −6.8 dB between output RF power and IF power and a spurious suppression ratio of > 43.5 dB. The experimental results show good agreement with theory and verify the effectiveness of microwave frequency converters based on coherent optical micro-combs, with the ability to achieve reduced size, complexity, and potential cost.

scholarly journals Emulator of a Boost Converter for Educational Purposes

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1883
Author(s):  
Paula Lamo ◽  
Ángel de Castro ◽  
Christian Brañas ◽  
Francisco J. Azcondo
Keyword(s):  
Current Mode ◽  
Boost Converter ◽  
Project Based Learning ◽  
Electronic Systems ◽  
Hardware In The Loop ◽  
Pulse Width Modulator ◽  
Digital Pulse ◽  
Digitally Controlled ◽  
Field Programmable ◽  
A Current

Project-based learning (PBL) is proposed for the development of a Hardware-in-the-Loop (HIL) platform and the design of its digital controller for an undergraduate course on Digital Electronic Systems. The objective for students is the design of a digitally controlled HIL Boost converter, a digital pulse-width modulator (DPWM) and a current mode controller, implemented in field-programmable gate array (FPGA) devices. To this end, the different parts of the project are developed and evaluated, maximizing the use of FPGA resources in the design of the HIL and DPWM blocks, and applying design techniques that minimize the use of the digital resources used in the design of the controller. Students are equipped with a new individualized educational experience, allowing them to test their technical competence and knowledge in an environment close to the reality of the industry.

Applied Research on the Closed-Loop Control of Oil Production System with Progressing Cavity Pump

2012 ◽  
Vol 248 ◽  
pp. 119-123
Author(s):  
Duan Yin Zhu ◽  
Jian Ning Xu ◽  
Yan Xiong Gao ◽  
Wen Jie Lv
Keyword(s):  
Production System ◽  
Closed Loop ◽  
Frequency Conversion ◽  
Rotation Speed ◽  
Frequency Converter ◽  
Dynamic Change ◽  
Oil Production ◽  
Closed Loop Control ◽  
Loop Control ◽  
Highly Efficient

It aimed to dynamic change of oilfield productivity, maked sure that the progressing cavity pump is working in a highly efficient region. It combined variable frequency conversion technology and dynamic liquid level height control technology, the closed-loop control of oil production system with progressing cavity pump is made up of rotation-speed and torsion sensor, stepless motor, frequency converter, PLC and progressing cavity pump. The result show that the system can control the pump submergence depth by adjusting the rotation-speed and torsion of polish rod, and make sure the pump working in a highly efficient region finally. This system also can increase recovery efficiency and pump service life.

Application of Frequency Converter Driver in Long Belt Conveyor

2011 ◽  
Vol 340 ◽  
pp. 19-22 ◽  
Author(s):  
Guo Huan Lou ◽  
Hai Li Yin ◽  
Shu Jie Li
Keyword(s):  
Frequency Conversion ◽  
Frequency Converter ◽  
Belt Conveyor ◽  
Long Distance ◽  
Adjustable Speed Drive ◽  
Constant Torque ◽  
Start Up ◽  
Torque Load ◽  
Adjustable Speed ◽  
Synchronous Drive

With the frequency converter for driving belt conveyor, the synchronous control of torque and speed for the belt-drive unit can be achieved and the start-up characteristics of belt conveyor can also be improved. This paper uses two methods for achieving synchronous drive of belt conveyor, one is synchronization through master-slave control of frequency converter itself, the second is adding external algorithm implemented by PLC systems. This article describes a variable-frequency adjustable-speed drive system used for long distance belt conveyor in mine main inclined shaft or ground. This frequency conversion device and system can be applied to the adjustable-speed drive process of constant torque load for conveyor.

Advance Control Experiment of Vibration Machine with High Vibration Intensity Based on SCM – Dynamics Characteristics and Advanced Control

2014 ◽  
Vol 912-914 ◽  
pp. 554-558
Author(s):  
Xiao Lan Yang ◽  
Ji Feng Liu ◽  
Meng Nan Si ◽  
Jia Wei Li ◽  
Biao Huang
Keyword(s):  
Frequency Conversion ◽  
Frequency Converter ◽  
Vibration Exciter ◽  
Vibration Machine ◽  
Vibration Intensity ◽  
Strongly Nonlinear ◽  
Advanced Control ◽  
Vibration Stress ◽  
Double Mass ◽  
Intensity Characteristic

The vibration-stress field could be formed by high vibration intensity in vibration machine to improve the ability of the collision, shock, shear and extrusion for the system, and it also can avoid plugging screen for vibration screening machine, which could make for solving some special requirements of the vibration machine. To research the vibration machines strongly nonlinear and high vibration intensity characteristic such as certain excitation and uncertain response, the vibration machine with its double-mass is built, and its vibration exciter uses two partial blocks as vibration motor. In addition, dynamic vibration differential equation is established. To achieve high vibration intensity results based on the vibration machines safe working, the advanced control based on the SCM and Intelligent frequency conversion is put forward, and the advanced control system with its host computer, frequency converter, SCM, charge-amplifier, sensor and the vibration machine is been established.

Sign in / Sign up

Export Citation Format

Share Document