Finding what antenna is used on a breakout board
The data sheet for an IC is usually a good place to look for reference designs




The manufacturer's website is also a source for information about antenna design - Quarterwave printed monopole antenna for 2.4GHz

See also


Why does an antenna trace have this shape?
http://www.ti.com/lit/an/swra117d/swra117d.pdf
http://www.silabs.com/Support%20Documents/TechnicalDocs/AN697.pdf