STC系列单片机不断电下载程序应用技术

针对单片机下载程序时需要重复机械式复位产生的一系列调试繁琐的问题,提出了一种用软件引导代替单片机硬件复位写入ROM的方法。该方法通过检测串口数据流是否合法,来判断是否执行ISP引导程序,从而利用软件方式复位,可以让STC单片机复位后从ISP引导程序处执行,利用该特性可以模拟单片机上电复位状态,实现单片机的不断电下载。

Design and theoretical study of a polarization-insensitive multiband terahertz metamaterial bandpass filter

We report the design of a novel multiband metamaterial bandpass filter （BPF） in the terahertz （THz）-wave region. The designed BPF is composed of a metal-dielectric-metal sandwiched structure with three nested rings on the top surface and a cross structure on the bottom surface. Full-wave simulation results show that the designed BPF has three transmission peaks at frequencies of 0.42, 1.27, and 1.86 THz with transmission rates of-0.87,-1.85, and-1.83 dB, respectively. Multi-reflection interference theory is introduced to explain the transmission mechanism of the designed triple-band BPF. The theoretical transmission spectrum is in good agreement with the full-wave simulated results. The designed BPF can maintain a stable performance as the incident angle varies from 0 to 30 for both transverse electric and transverse magnetic polarizations of the incident wave. The designed BPF can be potentially used in THz devices due to its multiband transmissions, polarization insensitivity, and stable wide-angle response in the THz region.

三波段超材料宽带带通滤波器的设计及实验研究

基于多个圆环嵌套结构单元,设计、加工与测试了一种对偏振无依赖以及大角度入射稳定的三波段超材料宽带带通滤波器(BPF)。仿真结果表明该滤波器存在三个通带,中心频率分别为7.22,10.10,14.46GHz,3dB相对带宽分别为17.5%,20.2%和17.4%,中心频率处透射率分别为-0.85dB,-0.69dB和-1.73dB。单元结构具有旋转对称性,使得该滤波器对电磁波偏振不敏感,并且在入射角达到40°时,三个波段依然维持较好的稳定性。通过监测谐振频点处的表面电流分布情况,分析了三波段滤波的物理机理。这种带通滤波器具有多波段滤波、偏振无依赖以及大角度入射稳定等特性,有望在多频谱成像技术、信息通信等领域发挥一定的作用。