introducing a shorting pin in circular patch antenna in ie3d

the circular match antenna raidus is taken as 27.7mm While modelling the coaxial probe feed to patch , the inner and outer diameters of the probe are taken as 1.3mm and 4.1mm respectively. it is loacated at a radial distance of 9.9mm fromthe center of patch towards its cicrcumference. A shorting patch is located at center with radius 0.5mm is connected through the ground and patch.

How can i solve this problem? Is the inner and outer diameters are necessary in the ie3d simulation or not?

Please reply as soon as possible