Problem with MWO

Hi, I've and important question about Microwave Office. I've designed a printed antenna that works perfectly when I simulate it but the measurements in laboratory are completely different. I think the problem could be in the ports. I use an edge port to feed the antenna using coplanar feeding, but I don't know if the simulator understand where is the ground or if I have to define it elsewhere ( once the antenna is built I feed it using SMA connector ans I put the ground pins at both sides of the coplanar line ). Any help could be grateful