Multiply resonant antenna device and electronic device including such and antenna device

摘要

According to one embodiment, a multiply resonant antenna device according to the embodiment includes a first antenna element formed from a monopole element, a second antenna element formed from a parasitic element placed at a position where it can be current-coupled to the first antenna element, and a third antenna element formed from a folded monopole element. The length of the first antenna element is set to nearly a ¼ of wavelength corresponding to the first resonant frequency. The length of the second antenna element is set to nearly a ¼ of wavelength corresponding to the second resonant frequency. The electrical length of the third antenna element from the feed point to a ground point through a folding end is set to nearly a ½ of wavelength corresponding to the third resonant frequency higher than the first and second resonant frequencies.