概括
这项研究介绍了一种新的可重新配置的超表面,用于电磁波的宽带控制. 它实现了振幅,相位和极化控制,使通信和隐形技术的先进应用成为可能.
科学领域:
- 电磁工程 电磁工程 电磁工程
- 材料科学是一种材料科学.
背景情况:
- 越来越复杂的电磁环境需要小型化和集成系统.
- 多功能可重新配置的超表面提供强大的电磁波操纵能力.
- 宽带多维电磁控制仍然是一个重大挑战.
研究的目的:
- 为宽带多功能散射控制提出一种新的可重新配置的极化转换元表面.
- 为了实现同时控制振幅,相位和偏振.
- 为了克服传统宽带阶段设计的局限性.
主要方法:
- 集成两个反平行PIN二极管来控制诱导电流方向.
- 对极化转换单元进行90°物理旋转的模拟.
- 利用电压控制电阻特征用于振幅和偏振控制.
主要成果:
- 宽带稳定1位相位转移的演示.
- 实现了宽带可重新配置的极化转换和雷达截面 (RCS) 控制.
- 试验验证光束转向和定型光束强度控制.
结论:
- 拟议的超表面成功实现了宽带多功能散射控制.
- 它在7-13GHz带宽中表现出双极化能力.
- 潜在的应用包括多重通信,智能隐形和雷达干扰.
相关概念视频
Transfer Function in Control Systems
The transfer function is a fundamental concept in the analysis and design of linear time-invariant (LTI) systems. It offers a concise way to understand how a system responds to different inputs in the frequency domain. It serves as a bridge between the time-domain differential equations that describe system dynamics and the frequency-domain representation that facilitates easier manipulation and analysis.
To derive the transfer function, consider a general nth-order linear time-invariant...
To derive the transfer function, consider a general nth-order linear time-invariant...
State Space Representation
The frequency-domain technique, commonly used in analyzing and designing feedback control systems, is effective for linear, time-invariant systems. However, it falls short when dealing with nonlinear, time-varying, and multiple-input multiple-output systems. The time-domain or state-space approach addresses these limitations by utilizing state variables to construct simultaneous, first-order differential equations, known as state equations, for an nth-order system.
Consider an RLC circuit, a...
Consider an RLC circuit, a...
State Space to Transfer Function
The conversion of state-space representation to a transfer function is a fundamental process in system analysis. It provides a method for transitioning from a time-domain description to a frequency-domain representation, which is crucial for simplifying the analysis and design of control systems.
The transformation process begins with the state-space representation, characterized by the state equation and the output equation. These equations are typically represented as:
The transformation process begins with the state-space representation, characterized by the state equation and the output equation. These equations are typically represented as:
Frequency-Domain Interpretation of PD Control
Proportional-Derivative (PD) controllers are widely used in fan control systems to improve stability and performance. A fan control system can be effectively represented using a Bode plot to illustrate the impact of a PD controller through its transfer function. The Bode plot visually conveys how PD control modifies the fan's response across various frequencies, providing a frequency domain interpretation of the controller's behavior.
The proportional control gain, combined with the system's...
The proportional control gain, combined with the system's...
Time and frequency -Domain Interpretation of Phase-lag Control
Phase-lag controllers are widely used in control systems to improve stability and reduce steady-state errors. A dimmer switch controlling the brightness of a light bulb serves as a practical example of phase-lag control, gradually adjusting the bulb's brightness. Mathematically, phase-lag control or low-pass filtering is represented when the factor 'a' is less than 1.
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any finite,...
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any finite,...
Load-frequency control
Load-frequency control (LFC) is vital for maintaining power system stability, ensuring that frequency and power flows remain within acceptable limits during load changes. Turbine-governor control eliminates rotor accelerations and decelerations following load changes. However, a steady-state frequency error persists when the change in the turbine-governor reference setting is zero. In an interconnected power system, each area agrees to export or import a scheduled amount of power through...


