Patent attributes
In order to have an antenna apparatus small in size and capable of switching its directivity pattern without degrading its antenna efficiency, the present invention provides an antenna apparatus having a driven element formed at an approximately center position of a planar printed circuit board and parasitic elements not performing feeding formed before and behind the first antenna element, respectively, so that the driven element is caused to function as a radiator and either one of the parasitic elements is made to have a length as long as an electrical length of a radiator or slightly shorter than that to function as a director and the other one of the parasitic elements is left to have an electrical length longer than that of the radiator to function as a reflector.
