PCB antenna in 20mm circle PCB

[nan]

Above is the "inverted—F" PCB antenna referenced.Below is the RF SCH and PCB layout,the PCB diameter is 20mm.Chip we use nrf51822 and bal-02d3. Can the antenna work well here? Is there any question?

[Reinier Gerritsen]

Hi,

Your feed point is extended by the vertical pcb trace. It is not a 50 Ohm transmission line because there is no GND plane underneath. So in effect, you have a series inductance to your intended antenna feed point. Was that intentional?