See, C.H., Abd-Alhameed, R.A., Jones, S.M.R., Zhou, D., McEwan, N.J., Excell, P.S., Elmegri, F., Noras, J.M., "Planar monopole antennas for new generation mobile and lower band ultra-wide band applications", IET Microwaves, Antennas & Propagation, 2012