Antenna Device and Wireless Communication Device Using the Same
An antenna device including a first Planar Inverted F Antenna (PIFA) operating at a first frequency and a second PIFA operating at a second frequency that is higher than the first frequency and disposed in a state in which it is insulated from the first PIFA. The antenna device has an antenna element in which a first short-circuit lead wire and a second short-circuit lead wire are coupled to a ground terminal provided on a substrate, a first feeding lead wire is coupled to a feeding terminal provided on a substrate via first matching circuit and a second feeding lead wire is coupled to a feeding terminal provided on the substrate via a second matching circuit. Thus, an antenna device which has a high degree of freedom for adjusting characteristics corresponding to a plurality of frequency bands can be realized.
1 . An antenna device comprising:
a first radiation conductor operating at a first frequency;
a first feeding lead wire coupled to the first radiation conductor;
a first matching circuit coupled to the first feeding lead wire;
a first short-circuit lead wire coupled to the first radiation conductor and grounded;
a second radiation conductor disposed in a state in which it is insulated from the first radiation conductor and operating at a second frequency that is higher than the first frequency;
a second feeding lead wire coupled to the second radiation conductor;
a second matching circuit coupled to the second feeding lead wire;
a second short-circuit lead wire coupled to the second radiation conductor and grounded; and
a transmitting/receiving circuit coupled to the first matching circuit and the second matching circuit.
2 . The antenna device of claim 1 ,
wherein the first short-circuit lead wire and the second short-circuit lead wire are disposed between the first feeding lead wire and the second feeding lead wire.
3 . The antenna device of claim 1 ,
wherein the first short-circuit lead wire and the second short-circuit lead wire are coupled to each other at their bottom parts.
4 . The antenna device of claim 1 ,
wherein the first radiation conductor and the second radiation conductor are formed on a surface of or inside a spacer made of a dielectric substance.
5 . The antenna device of claim 1 ,
wherein the first radiation conductor and the second radiation conductor are formed on different surfaces.
6 . The antenna device of claim 1 ,
wherein at the first frequency, an impedance of the second radiation conductor is higher than an impedance of the first radiation conductor.
7 . The antenna device of claim 1 ,
wherein at the second frequency, an impedance of the first radiation conductor is higher than an impedance of the second radiation conductor.
8 . The antenna device of claim 1 ,
wherein the first radiation conductor and the second radiation conductor are provided with a crosspiece for adjusting a frequency.
9 . The antenna device of claim 1 ,
wherein the first matching circuit comprises a high-pass circuit, and the second matching circuit comprises a low-pass circuit, respectively.
10 . The antenna device of claim 4 ,
wherein a terminal for holding an antenna element is provided in a region facing a region in which the first and second feeding lead wires and the first and second short-circuit lead wires are coupled, respectively.
11 . The antenna device of claim 1 ,
wherein at the first frequency, a load impedance of the transmitting/receiving circuit is substantially equal to an impedance from the first matching circuit to the first radiation conductor, and
at the second frequency, a load impedance of the transmitting/receiving circuit is substantially equal to an impedance from the second matching circuit to the first radiation conductor.
12 . The antenna device of claim 1 ,
wherein an angle made by a plane of the first short-circuit lead wire and a plane of the second short-circuit lead wire is substantially 90°.
13 . The antenna device of claim 4 ,
wherein on a contour of the spacer, an open end of the first radiation conductor and an open end of the second radiation conductor are disposed facing each other.
14 . A wireless communication device using the antenna device of claim 1 .
15 . A wireless communication device using the antenna device of claim 2 .
16 . A wireless communication device using the antenna device of claim 3 .
17 . A wireless communication device using the antenna device of claim 4 .
18 . A wireless communication device using the antenna device of claim 5 .
19 . A wireless communication device using the antenna device of claim 6 .
20 . A wireless communication device using the antenna device of claim 7 .
21 . A wireless communication device using the antenna device of claim 8 .
22 . A wireless communication device using the antenna device of claim 9 .
23 . A wireless communication device using the antenna device of claim 10 .
24 . A wireless communication device using the antenna device of claim 11 .
25 . A wireless communication device using the antenna device of claim 12 .
26 . A wireless communication device using the antenna device of claim 13 .