I am having issues with matching the S-parameters for Prob 4.28a from pozar that ADS throws up and the ones that i ended up from my manual calculations.
I am using a micro strip with 50ohm char impedance
manual calculations say that S11 is 1/3
But, ADS says it is 0.0002
can somebody help me out....quick reply will be helpful
for the sake of clarity, i had simulated the same microstrip using HFSS. That throws me a altogether different result. please look at the attached file
Looking at your ADS file. You have two 50 ohm ports. In between you have a 50 ohm transmission line. That will give you a VERY low mag(s11) and a VERY high return loss. Just like you get in your ADS simulation.
I do not know this problem 4.28a from Pozar. But if it is to put a 50 ohm transmission line in a 50 ohm system and then get a reflection coefficient og 1/3 it is incorrect.
I do not know if you study..... but take a look in the above mentioned book by Pozar. In the very simple question you have you usually calculate the reflection coefficient at the load(port 2) and then transfer it down the transmission line.
I hope you are familiar with the basic formula to calculate the reflection coefficient: \[\Gamma=\frac{Z_{l}-Z_{0}}{Z_{l}+Z_{0}}\]
Anyways please read some books
I am not able to calculate them manually. I do have enough knowledge of the basic formula's. pls find the attachd file.
If i try to calculate the value of the element "Z" from the graphs, i see that it varies greatly with frequency. I dont know how can calculate these values from the basic formula
I think you have mixed up a lumped element "Z" and the distributed nature of a transmission line Zo. So when you simulate, it is not a transmission line between the ports but a lumped element, capacitor, inductor or resistor.
no buddy.....I am still simulating it as a distributed element. I am using a microstrip. just for clarification, if i use those 4 values that i had mentioned in the previous attachment, I am seeing that S11 is indeed correct.
So, the problem is how can i replicate the behaviour of S11 using Z as a microstri[p of Z0 = 50 ohm on paper