Design rf trace antenna 433MHz + 315MHz on pcb
Texas Instruments has an excellent application node on antenna design. 
Antenna design from scratch is not a trivial exercise and if you don't have experience or access to expensive modeling software, you'd be best using a proven reference design. There are probably countless other reference designs for a 433Mhz and 315Mhz PCB antenna. Be careful though, a multi-antenna system can be a completely different beast than a single antenna system.