[Moved]: ERROR identification in antenna designing

hey i have design a microstrip patch antenna at freq 2.45GHz using guide from balanis book for antenna theory. my results are best coming at 2.4 GHz not at 2.45, what could be the possible error.

reduce the width of the antenna for optimization . it may occur due to the boundary conditions, feeding points...etc

theory is always different from simulation, you should rely on momentum simulation, and keep some placeholder for tuning

can you tell me how to find the impedance of antenna at different points in ADS?

u can plot smith chart in ads