Planar monopole antennas for new generation mobile and lower band ultra-wide band applications

This study presents two multiband planar printed monopole antennas with an optimised size of 57×37.5×0.8×mm³ for mobile/wireless and low-band ultra-wide band (UWB) applications. Both these antennas are constructed as a chorded crescent-shaped radiator, a feed line and a defected ground plane. The experimental and computed results confirm that one design offers a wide usable impedance bandwidth of 114.3%, with a reflection coefficient %S₁₁|||10|dB, over 1.5-5.5GHz. The other incorporates a tapered sickle-shaped slot in the radiator and demonstrates a band-suppression feature giving rejection of the worldwide interoperability for microwave access band (3.4-3.69GHz) where this is not required. The gains and far-field patterns of the antennas are presented and their group delay over the lower band UWB frequency range is also discussed.