Antenna device
An antenna device includes: a planar antenna; and a metal body arranged a predetermined distance above the planar antenna, wherein the metal body is shifted in a predetermined direction with respect to the planar antenna, wherein the metal body is a metal plate and/or a parasitic element. The antenna device further includes an antenna which corresponds to a frequency band different from that of the planar antenna and a holder configured to maintain the predetermined distance between the planar antenna and the metal body, wherein the antenna is arranged in the predetermined direction.
1. An antenna device configured to be attached to a vehicle, comprising:
a case having an accommodating space formed therein and having a radio wave permeability; and
an antenna portion configured to be accommodated in the accommodating space,
wherein the antenna portion comprises:
an antenna having a capacitance loading element; and
two communication system antennas arranged such that the antenna having the capacitance loading element is interposed between the two communication system antennas,
wherein at least one of the two communication system antennas is arranged below the capacitance loading element, and
wherein the bandwidth of the frequencies used by the communication system antenna arranged below the capacitance loading element is narrow.
2. The antenna device according to claim 1 , wherein the two communication system antennas use frequencies within substantially the same frequency band.
3. The antenna device according to claim 1 , further comprising a satellite system antenna, wherein the satellite system antenna is arranged in the accommodating space and at front side of the vehicle with respect to both the antenna having the capacitance loading element and the two communication system antennas.
4. The antenna device according to claim 3 , wherein the satellite system antenna is arranged at a front of the telephone antenna, and the antenna having the capacitance loading element is arranged at a rear of the telephone antenna.
5. The antenna device according to claim 3 , wherein the loading capacitance element includes an electrical delay circuit.
6. The antenna device according to claim 5 , wherein the electrical delay circuit is formed into at least one of a meandering shape, a shape having at least one folded portion, a zigzag shape, a winding shape, and a fractal shape.
7. The antenna device according to claim 1 , wherein at least one of the two communication system antennas is a telephone antenna.
8. The antenna device according to claim 1 , wherein at least one of the two communication system antennas is arranged at a rearmost portion of the vehicle in the accommodating space.
9. The antenna device according to claim 1 , wherein an electrical length of the capacitance loading element is a length that does not resonate in a frequency band used by the two communication system antennas.
10. The antenna device according to claim 1 , wherein an electrical length of the capacitance loading element is a length which does not resonate either in a frequency band used by at least one of the two communication system antennas or in a frequency band of the satellite system antenna.