how to increase circular patch antenna with a slot

hello.. Am designing antenna in HFSS a circular patch UWB wearable antenna with two slots (tilted square and circular) operating frequency i have considered is 5GHz ..taking substrate material as flannel fabric/jeans having dielectric constant of 1.7 and thickness of 1mm, L=30mm W=30mm. Radius of patch i have taken as 13.48mm for 5GHz freq ..Am getting resonant freq as 5.2GHz, VSWR below 1.5 ,impedence matching also happening..but am feeling difficulty regarding gain because am getting negative gain .please help me how to increase the gain of this antenna..

Hi,
Two slots on circular patch give rise to a circular polarized antenna...
I suppose you've only one feed ? Perhaps your slots are not optimized and your two degenerate mode are not properly excited.

Regards

could you share your hfss proyect?
i would deeply thank you