2port Z or Y parameter simulation problem

Dear all,

I have a 2-port DUT circuit. I connect port-1 is a input port and port-2 is a output port. I am using Spectre simulator. During S-parameter setting, it provides a box to select which port doing s-parameter simulation. I found that the Z or Y paramenter simulated result is different if I select just one port or two port in s-parameter simulation. Which result is correct?

I simulated the Y parameter under selecting input port in the s-parameter simulation. And then makes the equivalent circuit and uses it as output loading. I connect this equivalent circuit in my LNA output. The simulation result is same as the actual DUT connects in my LNA output. On the other hand, I simulated the Y parameter under selecting input and output port in the s-parameter simulation. Then makes the corresponding equivalent circuit and uses it as output loading. Also, I connect this equivalent circuit in my LNA output. The simulation result is dfferent as the actual DUT connects in my LNA output. So, it makes me confuse.

Thanks,

wccheng

Wic tool u r using?

s-parameter simulation is diffirenced with Y and Z parameter. when software simulated s11 in port-2, port-2 will be seen as 50ohm R.In Y and Z parameter simulation port-2 should be seen as open. So if cal Z and Y Para using S para , should be careful.

You should determine the type of your circuit, one-port or two-port. For example, if the circuit is an antenna, then it should be one-port. On the contrary, if it is a matching network, it should be two-port. To connect the two-port circuit to the LNA output, you should specify the termination of the two-port circuit.