Designing a 315 MHz antenna on flexible substrate!!! 1

I am currently playing around with ideas on designing a antenna on a flexible substrate like a copper foil. One side is a polystyrene and the other is a 1 oz copper cladding.

I have tried a quarter wavelength patch antenna. Basically a square with a short 1.25 cm long feed point from the RF circuit to the patch. If the outside dimensions is a quarter wave than it will fit in my housing.

Anyone try a slot antenna or possibly a circular patch design? Please do not limit yourself to these ideas.

thanks