If you have already an optimized antenna design then you have to model a capsule and place your conformal antenna inside that. Then you can use a human body model for simulation modelling purposes. The planar antenna can be conformed around the capsule interior to form the conformal antenna.

Thanks for the answer. To place the capsule inside the human model, will it have an overlap area between these two?

Yes, there will be overlap area.

Create the material " ingestible capsule" by defining dielectric and other conductivity properties, then model the antenna along with the capsule (Antenna on a other dielectric material, which may be having different shape (capsule)).... If they are overlapping then addition and subtraction of same materials need to be done properly......

Thanks both of you so much.

What methods/programms do you use to model the capsule ? Are there any tutorials available?

Thanks in advance!