Compact Octagonal Monopole Antenna Employing T-Shaped Quasi-Self-Complimentary Resonators for Tri-Band Operation

A novel tri-band monopole antenna design employing Tshaped quasi-self-complimentary (QSC) resonators is presented. The proposed antenna is composed of a pair of symmetrical QSC resonators, an octagonal monopole radiator and two L-shaped slots. By utilizing these structures, the antenna can yield different resonances to cover the desired bands while maintaining small size and simple structure. Based on this concept, a prototype of tri-band antenna is designed, fabricated and tested. The experimental results show that the antenna has the impedance bandwidths of 190 MHz (2.36–2.55 GHz), 680 MHz (3.37–4.05 GHz) and 1760 MHz (5.12–6.88 GHz), which can cover both WLAN in the 2.4/5.2/5.8 GHz bands and WiMAX in the 3.5 GHz band.