PORT in Advanced Design System

hi to my friends.
who can explain that what is applied to a PORT in ADS/layout envirenment .
and is there important the value of components in momentum simulations ?
for example is it any diffrences between a momentum simulation that its layout have a resistor of 1kohms and another momenyum simulation that its layout have a resistor of 1Mohms ?
or if in the momentum simulations , that is only important to final results , is the place of shapes and the material of conductor and dielectrics and the physical charachteristics of the layout ?

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