考虑一种同轴电缆，其外导体“O”具有无限长度，但内部导体“I”具有一定的有限长度，正如我试图用下面的ASCIII图形所示。今晚我喝了不少啤酒，所以不要想我试图在图形包中画这个啤酒！观察到左侧的S参数是否已经被异步地推进并且已经发表了？具有足够的S-参数是否已经被发现？如果是这样，有没有人有参考？显然，这样的结构作为校准标准相对容易制作* IF *这些属性可以在理论上得到。我可以想象这是某种人可能想要解决的结构，我可以想象有可能达到解决方案。我也可能会假设它会涉及贝塞尔函数，这对于驱逐程序来说是非常重要的。如果内部被翘曲，但是被电介质D支撑则更有用，例如，如使用安捷伦的EMPro或Ansys的HFSS这样的3D EM求解器，当然可以相当容易地用数字方式来推测S参数，这是非常有用的。 ，但我想知道是否有人对这些结构中的任何一个都有理论解决方案？ Dave.Edited：drkirkby于2013年7月28日下午10:48 以上来自于谷歌翻译 以下为原文Consider a coaxial cable which has an outer conductor "O" of infinite length, but an inner coductor "I" of some finite lenght, as I've tried to show with ASCIII graphics below. I've had quite a few beers tonight, so don't fancy my chances trying to draw this in a graphics package!!! OOOOOOOOOOOOOOOOOOOOOOOOOOOO IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII OOOOOOOOOOOOOOOOOOOOOOOOOOOO Have the S-parameters looking into the left hand side ever been derrived theoertically, and published? If so, does anyone have a reference? Clearly such a structure would be relatively easy to make as a calibration standard *IF* the properties could be derrived theoretically. I can imagine it is the sort of structure someone might have thought to solve, and I can imagine it might be possible to arrive at a sollution. I might also postulate it would involve Bessel functions an be non-trivial to derrive. Even more useful would be the case if the inner was tructated, but supported by a dielectric D, as in OOOOOOOOOOOOOOOOOOOOOOOOOOOOO IIIIIIIIIIIIIIIIIIIIIIIIIIIIIDDDDDDDDDDDDDD OOOOOOOOOOOOOOOOOOOOOOOOOOOOO It would of course be fairly easy evualate the S-parameters numerically with a 3D EM solver such as Agilent's EMPro or Ansys's HFSS, but I wonder if anyone has a theoretical solution to either of these structures? Dave.Edited by: drkirkby on Jul 28, 2013 10:48 PM
2019-01-17 10:51
首先，祝大家圣诞快乐。我花了一些圣诞节来讨论我的8720D VNA - 它是由我个人拥有的，因此在我的家里，所以它不像它看起来那么不干净！我感兴趣的是看一个未连接的公N连接器是否可以用作“开放式”校准设备，如果是，那么哪个参数最好。好吧，我知道它可以完成，因为FieldFox系列上的QuickCal可以做到这一点，但当然我需要参数进入VNA。如果他们是安捷伦的老手，我也不会感到惊讶。首先使用适当的'N'校准套件（85032B）进行校准后，我注意到以下情况。 1）令我惊讶的是，开放式N似乎不是电容性的，因为我认为由于边缘电容。相反，它似乎是归纳的。是否能够通过值为2的电容器来表示电感。中心导体位于参考平面下方约1 mm。鉴于真空中的光速为299792458 m / s，这表明输入的偏移应为-0.001 / 299792458 = -3.335 ps。那有意义吗？也许值得说明偏移几ps - 使其更负面，因此可以将电容作为正值输入。我不确定这是否比使用负电容更好或更差。对于它的价值，我最初尝试通过曲线拟合找到C0，C1，C2和C3的合理值并不太成功，但我怀疑它有更多的时间可能是可行的。如果有人试过这个，或者知道参考文献，我会感兴趣的。你可能觉得我很生气，但现在是圣诞节，所以我喝了一两杯啤酒！有了这一切，一切顺利。我要去爱尔兰咖啡吧！ （这在英国很受欢迎 - 对美国不太确定。我猜你可以用杰克丹尼尔威士忌制作它。）如果我说实话，我用一种廉价的苏格兰威士忌制作“爱尔兰咖啡”。我认为将更昂贵的爱尔兰威士忌放入咖啡中是不合理的。戴夫 以上来自于谷歌翻译 以下为原文First of all, merry Christmas to everyone. I've spent some of Christmas day messing around with my 8720D VNA - it is personally owned by me, hence in my home, so it was not quite as unsociable as it might appear! I was interested in see if an unconnected male N connector could be used as an "open" calibration device, and if so what parameters would be best. Well, I know it can be done, as the QuickCal on the FieldFox range do this, but of course I needed the parameters to enter into the VNA. and I would not be surprised if they are proprietry to Agilent. I noticed the following, after first calibrating with a proper 'N' calibration kit (85032B). 1) Much to my surprise, the open-N does not appear to be capacitive, as I would have thought due to the fringing capacitance. Instead, it appears inductive. Would it make sence to represent an inductance by capacitor of a value < 0 ? I found it is possible to enter negative values for all value C0, C1, C2 and C3. . 2) The centre conductor sits below the reference plane by about 1 mm. Given the velocity of light in a vacuum is 299792458 m/s, that would suggest the offset to be entered should be -0.001/299792458 = -3.335 ps. Does that make sense? Perhaps it is worth lying about the offset by a few ps - making it even more negative so it is possible to enter the capacitance as a positive value. I'm not sure if that would be better or worst than having negative capacitors. For what it is worth, my initial attempts to find sensible values for C0, C1, C2 and C3 by curve fitting were not too successful, but I suspect with more time it might be workabe. If anyone has ever tried this, or knows of a reference, I'd be interested. You probably think I am mad, but it is Christmas day, so I have had a beer or two! With that, all the best. I'm going to have an Irish Coffee! (That's quite popular in the UK - not so sure about the USA. I guess you could make it with Jack Daniels whisky.) If I'm honest, I make an "Irish Coffee" using a cheapish Scotish whisky. I think putting the more expensive Irish whisky in a coffee is not justified. Dave
2019-04-28 11:34
本文来自2018 年6 月25 日出版的《 中兴通讯技术 》，作者是中兴通讯股份有限公司无线经营部朱伏生总工。雷达通信的概念约在21 世纪初被提出来 [1-5]，雷达通信一体化概念的提出则是为了适应未来高科技战争。雷达系统和通信系统作为电子战平台的基本组成部分，在军事方面的作用至关重要。长期以来，这些系统都是各自纵向发展，但随着技术的进步，各系统间的差距逐渐减少，于是系统间的横向一体化发展问题开始受到关注，即从横向上对现有系统进行融合，使其具备通用性和多功能性。如果能实现雷达通信一体化，不仅能够减少电子战平台的体积和电磁干扰，更可以提升战场指挥效率。虽然雷达系统和通信系统由于用途的不同在工作方式、功能实现和信号特征等方面都存在显著差异，但从系统原理来看，雷达技术和通信技术都与电磁波在空间的发射和接收有关。从系统结构来看，两者的硬件系统都包括天线、发射机、接收机和信号处理器等模块；从技术的发展趋势来看，雷达由传统硬件器件实现的功能正在由数字信号处理来取代完成。同时，通信系统的载频也转移到微波领域，与传统雷达使用的频率处于同一数量级。因此，雷达系统和通信系统从硬件结构实现到软件算法处理都正在趋同。雷达系统和通信系统的一体化首先是以共用相同的硬件平台为基础。最简单的是时分共享的方式，利用选通开关，雷达系统和通信系统分时复用天线、发射机和接收机等硬件平台，但是这种方式下两个系统都不可能连续长时间地占用资源，否则就会影响另一个系统的性能；而本系统也由于工作时间有限而使得系统性能受限。另一种硬件平台共享的方式主要用于相控阵雷达，将二维阵列分成多个子阵，每个子阵独立工作，用于实现雷达或通信功能，但是由于子阵的功率受限，雷达和通信系统的性能都会受到影响。因此，这种硬件共享、独立实现雷达和通信功能的一体化技术由于资源受限不仅对系统性能有影响，而且限制了系统效率的提升。因此，近年来雷达通信一体化的研究开始关注信号方面的融合，即在同一硬件平台上利用同一信号实现雷达和通信功能。车载雷达通信系统利用车辆已经装载的毫米波雷达以及雷达通信一体化技术，不仅可以实现车载雷达探测和车间通信功能，而且不会额外增加汽车的硬件模块，也不会因为通信功能的引入而使得汽车的电磁环境更加复杂，既降低成本又可以提高频谱利用率。因此，车载雷达通信系统将会成为雷达通信一体化技术从军事应用转向民用领域的重要突破之一。
2019-06-19 06:52
