是否有一种简单的方法可以直接在ADS中模拟负阻设备，如隧道二极管？

最近，我决定尝试在旧的HP 1425A时基中创建一个触发输入电路的ADS模型，原因是我仍然使用一个，我希望能够弄清楚如何稍微改善系统的带宽，以及
也许还要使其适应现代替换元件，因为输入中使用的二极管没有替代源。
几乎立即，在开始这个时，我意识到在ADS中似乎没有通用的隧道二极管模型。
不用说，我并不是很惊讶，这似乎是电路模拟器的常态。
我能够跟踪Aeroflex的一个文件，描述如何在spice中对它们进行建模，所以我应该能够这样做并导入文件，但所有这些让我想知道我是否以正确的方式进行了这项工作。
我对ADS很新，所以我在为单个组件创建模型方面经验很少，但是在spice中对事物进行建模然后导入它们似乎是解决问题的一个相当不优雅的解决方案，所以我怀疑必须有
一种更简单，更快捷的方法。
因此，我的问题是，是否有一种简单的方法可以直接在ADS中模拟负阻设备，如隧道二极管？



     以下为原文

  Recently, I decided to try to create an ADS model of the trigger input circuits in the old HP 1425A timebases, the reason being that I still use one, and I was hoping to figure out how to improve the bandwidth of the system slightly, and perhaps also to adapt it to modern replacement components, since there is no source of replacements for the diodes used in the inputs.
Almost immediately, upon starting in on this, I realized that there appears to be no general purpose tunnel diode model in ADS. needless to say, I wasn't very surprised, this seems to be the norm for circuit simulators. I was able to track down a document from Aeroflex describing how to model them in spice, so I should be able to do that and import the files, but all of this made me wonder if I were going about this in the right way.  

I'm fairly new to ADS, so as yet I have very little experience creating models for individual components, but modeling things in spice and then importing them seems to be a fairly inelegant solution to the problem, and so I suspect that there must be an easier and faster way to do this. My question, thus, is whether there is a simple method to model negative resistance devices, like tunnel diodes, directly in ADS?