Dual-band annular slot antenna for radio base stations

This paper presents the study and design of a dualband linearly polarized annular slot antenna. The proposed antenna is designed for operation in the lower (0.824-0.960 GHz) and in the higher bands (1.710-2.165 GHz) of the Brazilian mobile communications system. The antenna is designed considering one output for each frequency band, so that both bands can be processed independently. Numerical results show that the antenna exhibits good performance in terms of return loss and radiation pattern in both bands. The proposed geometry has been manufactured and the experimental results are compared to numerical data. A parametric analysis for some antenna parameters is shown and the results discussed.