Loop-Monopole Composite Antenna for Dual-Band Wireless Communications

A novel loop-monopole composite antenna for wireless communications is presented. The proposed antenna is composed of a loop, a monopole, a horizontal ground plane and a vertical reflector. The antenna's operation principle is investigated and some design guidelines are laid down in the beginning. Then, an optimized loop-monopole composite antenna is designed. It is demonstrated that the antenna covers two bands from 2.16 to 3.21 GHz and from 4.24 to 7 GHz for |S
₁₁
| smaller than -10 dB. The antenna has stable, unidirectional radiation pattern within its pass-bands. The average gain of the antenna is 4.5dBi (lower band) and 7.7dBi (higher band). The proposed antenna can be used as an indoor base station antenna for multiband wireless communications.