I am trying to simulate CMRR and PSRR in ADS of a differential OTA. However, ican't obtain good results as you can see below:
I'm so grateful if you can help me to abtain wrong results by giving me a tutorial how to simulate the CMRR and PSRR in ADS
Your plot doesn't say anything. Show opamp schematics, CMRR/PSRR testbenches etc. A quick and effortless google/edaboard search can give you the right testbenches for both specs.