Wide band antenna for mobile communications

Claim 2

An antenna device (1) for vehicles, comprising a ground plate (2) having a flat surface, a L-shaped radiator plate (5) having one leg (5a) of L arranged parallel to said ground plate (2) with the other leg (5b) being po­sitioned perpendicular to said ground plate (2), said ra­diator plate being disposed having a narrow gap (6g1) between the lower end (5c) of said vertical leg (5b) and the upper surface of said ground plate, a feed coaxial cable (4) for connecting said ground plate with an outer conductor (4a) and also for connecting an inner conductor (4b) with substantially the center of said vertical leg end (5c) of said radiator plate, and a sub-radiator element (7) formed by a L-shaped plate rigidly mounted on said ground plate (2) at a position in close proximity to said radiator plate (5), said sub-radiator element (7) having one leg (7a) extending parallel to said ground plate (2) with the end (7b) thereof being spaced away from the end (5d) of the parallel leg (5a) of said radiator plate (5) by a given distance (8g2), the vertical leg (7c) of said L-shaped plate (7) having the end (7d) connected with said ground plate (2) to provide an increased resonant band width.

Claim 3

An antenna device as defined in claim 1, further comprising filler means (24) for surrounding said ground plate (2), said radiator plate (5) and said sub-radiator element (7), said filler means being made of dielectric material which has good high-frequency characteristics.

Claim 4

An antenna device as defined in claim 1, wherein filler means (9, 24) at least interposed between the ground plate (2) and the radiator plate (5) and between the ground plate (2) and the sub-radiator element (7).

Claim 5

An antenna device as defined in claim 3 wherein said filler means is made of one selected from Teflon, epoxy resin or glass.

Claim 6

S. An antenna device as defined in claim 3, further comprising support means (20) covering the part of the outer surfaces of said radiator plate (5) and said sub-­radiator element (7) for rigidly mounting said radiator plate and said sub-radiator plate on said ground plate (2)

Claim 7

An antenna device as defined in claim 5, the outer surface of said support means (20) has sloping outer wall faces for rounding off the outer surface thereof.

Claim 8

An antenna device as defined in claim 1, further comprising support means (20, 24) for rigidly mounting said radiator plate (5) on said ground plate (2) with the end of the vertical leg (5b) of said radiator plate (5) being floated above said ground plate (2) by a given narrow gap (6g1) therebetween, said support means being made of an electrically insulating material.

Claim 9

An antenna device as defined in claim 6 or 7, wherein said support means is made of foamed styrene.

Claim 10

An antenna device as defined in claim 7, wherein said support means (24) includes a molding resin which is set to surround said radiator plate (5) and said sub-radia­tor element (7) with said radiator plate (5) being spaced away from said ground plate by said given narrow gap (6g1)

Claim 11

An antenna device as defined in any of claims 1 to 9, wherein the length (L₁) of said radiator plate (5) is set to be slightly larger than one-fourth the wave-length λ of a carrier and wherein the length (L₂) of said sub-radia­tor element (7) is set to be slightly smaller than one-­fourth the wave-length λ of the carrier.

Claim 12

An antenna device for vehicles, comprising a ground plate (2) having a flat surface, a L-shaped radiator plate (5) having one leg (5a) of L arranged parallel to said ground plate (2) with the other leg (5b) being posi­tioned perpendicular to said ground plate (2), said radia­tor plate being disposed having a narrow gap (6g1) between the lower end (5c) of said vertical leg (5b) and the upper surface of said ground plate, a feed coaxial cable (4) for connecting said ground plate with an outer conductor (4a) and also for connecting an inner conductor (4b) with sub­stantially the center of said vertical leg end (5c) of said radiator plate, and a sub-radiator element (7) formed by a L-shaped plate being disposed close to said ground plate (2) at a position in opposite proximity to said radiator plate (5), said sub-radiator element (7) having one leg (7a) extending parallel to said ground plate (2) with the end (7b) thereof being spaced away from the end (5d) of the parallel leg (5a) of said radiator plate (5) by a given distance (8g2), the vertical leg (7c) of said L-shaped plate (7) having a connecting bridge portion (7a) rigidly connected with said ground plate (2) at one side of the vertical leg to widen a resonant band width.

Claim 13

An antenna device for vehicles, comprising a ground plate (2) having a flat surface, a L-shaped radiator plate (5) having one leg (5a) of L arranged parallel to said ground plate (2) with the other leg (5b) being posi­tioned perpendicular to said ground plate (2), said radia­tor plate being disposed having a narrow gap (6g1) between the lower end (5c) of said vertical leg (5b) and the upper surface of said ground plate, a feed coaxial cable (4) for connecting said ground plate with an outer conductor (4a) and also for connecting an inner conductor (4b) with sub­stantially the center of said vertical leg end (5c) of said radiator plate, and a sub-radiator element (7) formed by a L-shaped plate being disposed close to said ground plate (2) at a position in opposite proximity to said radiator plate (5), said sub-radiator element (7) having one leg (7a) extending parallel to said ground plate (2) with the end (7b) thereof being spaced away from the end (5d) of the parallel leg (5a) of said radiator plate (5) by a given distance (8g2), the vertical leg (7c) of said L-shaped plate (7) having a connecting bridge portion (7a) rigidly connected with said ground plate (2) at one side of the vertical leg to widen a resonant band width.

Claim 14

An antenna device as defined in claim 11, further comprising filler means (9) for surrounding said ground plate (2), said radiator plate (5) and said sub-radiator element (7), said filler means being made of dielectric material which has good high-frequency characteristics; wherein the length (L₁) of said radiator plate (5) is set to be slightly larger than one-fourth the wave-length λ of a carrier and wherein the length (L₂) of said sub-radiator element (7) is set to be slightly smaller than one-fourth the wave-length λ of the carrier.