2port Z or Y parameter simulation problem

[wccheng]

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

 

[faizahmed]

Wic tool u r using????

 

[chj26545481]

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.

 

[streamlet]

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.