怎么绕过内部耦合器

问候，我一直试图通过绕过测试端口的内部耦合器来提高我的N5230C PNA灵敏度。
为实现这一目标，我直接访问了内部微波硬件配置，并通过循环器路由信号。
请参阅附件。
我没有达到更好的灵敏度，但是我的测量质量比简单的1端口测量更差。
如果1端口测量结果具有或多或少的具有一些噪声的平坦迹线，则绕过内部耦合器会导致大量波纹。
我的测量设置中的问题在哪里？
我怎么能改进它？
最好的问候，KA



     以下为原文

  Greetings,

I have been trying to improve my N5230C PNA sensitivity by bypassing the internal coupler at the test port. To achieve this, I directly accessed the internal microwave hardware configuration and routed the signal through a circulator. Please, see the attachments. I did not achieve better sensitivity, but I made the quality of my measurements even worse than straightforward 1-port measurements. If the 1-port measurement results have a more or less flat trace with some noise, bypassing the internal coupler leads to lots of ripples.

Where is the problem in my measurement setup? How could I improve it?

Best regards,
KA   
附件

• Meas_Setup_Rev.pdf148.3 KB