Patent attributes
The method and apparatus described herein improves the impedance matching of a multi-band antenna. In particular, the multi-band antenna comprises a radiating element vertically displaced from an antenna ground plane by feed and ground elements, and a parasitic element interposed between the feed and ground elements. When the multi-band antenna operates in the first frequency band, a selection circuit connects the parasitic element to the ground plane to capacitively couple the ground element to the feed element. However, when the multi-band antenna operates in the second frequency band, the selection circuit disables the capacitive coupling. By applying the capacitive coupling only when the multi-band antenna operates in the first frequency band, the present invention improves the performance of the antenna in the first frequency band without adversely affecting the performance of the antenna in the second frequency band.
