missing one small electronic component on the board

Dear all,

I try to fix the board using a screw. However, I knock down one side (? not sure if it is another whole piece of component) of electronic component. Please see attached picture (red arrow).

It works when I run lighting up pin 13 LED.

Anyone can tell me what the component is for?

Thanks a lot.

|500x392

It is chip antenna.

If you have V.5 board, then use external antenna.