Dual polarized aperture coupled microstrip antenna (HFSS)

I am trying to design an aperture coupled microstrip antenna (5.8 GHz) which can support linear polarization on two orthogonal ports. I am planning on a classic two substrate sandwich with the ground plane (with orthogonal slots) in between, a circular patch on top on one side and the transmission line feeds on the bottom side. If someone has already worked on such a design I would like some pointers. Simulation will be done on HFSSv9.2