Design of broadband dual-band dipole for base station antenna

A novel dual-band unidirectional antenna composed of an irregular shorted patch and planar dipole elements is presented and studied. This proposed antenna employs an L-shaped feeding strip for exciting dual-band operations. For the lower frequency band, a V-slot is loaded on the planar dipole for acting as a capacitive loading for having wide impedance matching of the antenna. Then, two additional smaller planar dipoles are placed and connected to the irregular short patch for achieving another wideband performance at the higher frequency band. The proposed antenna has wide dual-band impedance bandwidths of 34% and 49.5% in the lower and the upper bands, ranged from 0.78 GHz to 1.1 GHz and from 1.58 GHz to 2.62 GHz, respectively. More importantly, the antenna has stable gains of 7 dBi and 8 dBi across each band, demonstrating the high stability of the radiation characteristic for the two radiation modes. The radiation patterns are symmetric, low back-lobe radiation and low cross-polarization. Analysis and parametric studies of the proposed antenna are provided. © 2006 IEEE.