Need help with test chip layuout for S21

[khabib]

Hello,
I am trying to layout some test structure for S21 measurement for substrate coupling. Please see
if you can help me with these answer

1. For calibrateion do I need only the open structure sinse I am measuring the S21.
2. If, I am measring the S21 for upto 10GHZ, can I assume the pad to be lumped element. That is
no need to match the pad for 50ohm characteristics impedence of the RF probe tips which is also 50ohm.

Please see if you can give any other help[.

Regards,

Kazi

 

[yjkwon57]

Hi~~

The pad are to be treated as a lumped element. But if you shields the pad by using some technique like the Faraday shield, the power dissipation from the interference between the pad and the other components near the pad will be little. Then, you can calibrate the s21 parameter by using the s11 parameter, since the real power flowed into the device will be 1 - s11.

I think the short is better than the open, since the short is more physically implementable than the open.

Bye~~~

 

[selvaraja]

Hi ,

You need to 50 ohm matching at signal i/o pad in order to probe them . if not the signal will refelected.

regards,

selvaraja