Patent ID: 7196665

Claim:
An antenna device comprising: a first antenna element transmitting and receiving a low frequency radio wave band; a second antenna element transmitting and receiving a high frequency radio wave band, wherein, the first antenna element and the second antenna element are disposed so as to face each other, above a wiring board of a radio device, and a distance between the first antenna element and the ground of the wiring board is longer than a distance between the second antenna element and the ground of the wiring board, the antenna device transmits and receives two frequency radio wave bands with the first antenna element and the second antenna element, and the first antenna element supports GSM and the second antenna element supports one of DCS and PCS, and the antenna device is used for a portable phone, wherein, a distance between the first antenna element and the second antenna element is substantially equal to the distance between the second antenna element and the around of the wiring board, wherein, facing region between the first antenna element and the second antenna element is an empty space, and distance D 1 between the first antenna element and the ground of the wiring board and distance D 2 between the second antenna element and the ground are set in a range expressed by D 2 /D 1 =λ LMIN /λ HMAX to λ LMAX /λ HMIN , where λ LMAX and λ LMIN are a wavelength of a radio wave corresponding to a maximum frequency of the low frequency band and a wavelength of a radio wave corresponding to a minimum frequency of the low frequency band, respectively, and λ HMAX and λ HMIN are a wavelength of a radio wave corresponding to a maximum frequency of the high frequency band and a wavelength of a radio wave corresponding to a minimum frequency of the high frequency band, respectively.