Forum Post: RE: CC2540 board thickness effect on antenna

For an existing PCB antenna design should antenna impedance be measured. If needed can antenna shape be adjusted but better is to leave space on PCB for a matching network. It is simpler to adjust matching net component values then adjust PCB layout. Antenna impedance is measured with a Vector Network Analyzer and matching network component values/schematic can then automatically be read using a suiting impedance matching software.
At www.antune.net/demo/bluetooth/index.html is an easy step for step instruction how to design and impedance match an PCB Bluetooth antenna in 5 minutes.