二次雷达系统干扰等问题的解决方法

二次雷达是一个与一次雷达相对应的概念,在实际应用中,二次雷达想要真正的发挥出作用,需要充分结合目标发射的信号,因此二次雷达系统中需要同时配置询问机和应答机。近年来,现代军事战争以及航空管制领域越来越多的应用到二次雷达系统,通过对目标进行精准的判断来实现角色识别,确定敌我关系。同时二次雷达在使用过程中对于信号的完整性以及准确性要求较高,但是目前的二次雷达信号传输还是存在着一定的影响因素导致信号质量受到干扰,基于上述论述,对二次雷达系统进行基本的分析研究是十分必要的,同时需要研究系统的干扰问题并采取一定的措施解决上述干扰,实现二次雷达在各个领域更加有效的应用。

Plasmon-induced transparency effect in hybrid terahertz metamaterials with active control and multi-dark modes

We numerically demonstrate a photo-excited plasmon-induced transparency(PIT)effect in hybrid terahertz(THz)metamaterials.The proposed metamaterials are regular arrays of hybrid unit cells composed of a metallic cut wire and four metallic split-ring resonators(SRRs)whose gaps are filled with photosensitive semiconductor gallium arsenide(GaAs)patches.We simulate the PIT effect controlled by external infrared light intensity to change the conductivity of GaAs.In the absence of photo excitation,the conductivity of Ga As is 0,thus the SRR gaps are disconnected,and the PIT effect is not observed since the dark resonator(supported by the hybrid SRRs)cannot be stimulated.When the conductivity of GaAs is increased via photo excitation,the conductivity of Ga As can increase rapidly from 0 S/m to 1×10^(6)S/m and GaAs can connect the metal aluminum SRR gaps,and the dark resonator is excited through coupling with the bright resonator(supported by the cut wire),which leads to the PIT effect.Therefore,the PIT effect can be dynamically tuned between the on and off states by controlling the intensity of the external infrared light.We also discuss couplings between one bright mode(CW)and several dark modes(SRRs)with different sizes.The interference analytically described by the coupled Lorentz oscillator model elucidates the coupling mechanism between one bright mode and two dark modes.The phenomenon can be considered the result of linear superposition of the coupling between the bright mode and each dark mode.The proposed metamaterials are promising for application in the fields of THz communications,optical storage,optical display,and imaging.

基于回音壁模式微泡腔的流速传感应用

基于黏性流体的伯努利效应原理,利用回音壁模式微泡腔高品质因子与具有天然微流控通道的特性,提出一种基于回音壁模式微泡腔的流速传感器。理论分析了黏性流体流动时由于黏滞损耗引起的压强损失,仿真分析了不同流速范围内流动速度和压强之间的关系,发现二者之间表现出良好的线性依赖,沿程损耗是引起压强损失的主要因素;恒定流速下微腔内部为均匀的正压分布,会引起谐振波长红移。实验制备了壁厚约为2μm的微泡腔,并搭建流速传感实验测试系统。在3~106μL/min流速范围内,流速增加时,谐振波长发生红移,并且波长偏移与流速之间满足良好的线性关系,拟合得到流速传感灵敏度为0.047 pm/(μL/min),检测极限为0.635μL/min。该流速传感器结构简单、易于制备、低成本且检测极限较低。