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?

[Håkon Alseth]

There are two things that I can pin-point to regarding the range, other than what other users have suggested. The first thing is that you're lacking an antenna tuner network (PI-network). This is essential for every antenna, as every design has different characteristics in terms of stray capacitance, component placement, ground plane, layers, PCB size and shape, and the casing usually has effect on the antenna impedance.

Each design is unique in terms of the antenna impedance. If you have a perfect 50 ohm antenna for one design, and copy it into a completely different design, you're not guaranteed the same performance.

There are a couple of threads on this:

devzone.nordicsemi.com/.../ devzone.nordicsemi.com/.../

The second thing, if you're testing with the internal DCDC enabled (we do not recommend using it), you may see reduced range due to the DCDC's stabilizing time causing ripple on certain regulators internally, thus raising your noise level in RX (and you'll get a dirty TX modulation).

[Jose Xavier]

What do you suggest to not use the DCDC internal regulator?