antenna in 20mm circle PCB

[nan]

In the picture, the usb pcb is PCA10000, the circle PCB is the product PCB.

The diameter is 20mm.

Chip antenna is used now but the distance is 5m in 4dbm TX.

Here is the PCB layout, and RF SCH.

Is there any good antenna solution?

I can spend money for tune the antenna.

Is PCB antenna better?

[Janek Mann]

You would struggle to fit a well-performing PCB antenna in the same space as that chip antenna. Though, as you experienced, a small chip antenna doesn't perform great either. Your best option is certainly to make more space for the antenna (at least in my experience). Your ground plane is not fantastic though (there's a huge slot created by the power trace, I would try to break up that power trace to get a better ground plane). For a really small antenna, the Molex "on-ground" one is excellent: www.molex.com/.../479480001_sd.pdf

[nan]

Which kind of PCB antenna is better? any suggestion?