Dual-resonance monopole antenna with tuning stubs

A dual-resonance monopole antenna is proposed for application in mobile communications devices. The antenna is small in comparison with conventional monopole antennas as only one resonator is used to realise dual-resonance operation. The frequency ratio of the dual resonance is adjusted by employing a number of tuning stubs. It is demonstrated that GSM (Global System for Mobile Communications) tri-band operation including GSM900 (880–960 MHz), GSM1800 (1710–1880 MHz) and GSM1900 (1850–1990 MHz) can be achieved by using the monopole antenna with an overall size of 20×20×1 mm3 for a conventional handset.