T.-G Ma, S.-J Wu, “Ultrawideband Band-Notched Folded Strip Monopole Antenna ", IEEE Transactions on Antennas and Propagation, Volume: 55  Issue: 9, Sept. 2007, Page(s): 2473-2479

The publication is available to download from http://ieeexplore.ieee.org/xpl/tocresult.jsp?isnumber=4298161&isYear=2007