US 6,307,520 B1Granted

Boxed-in slot antenna with space-saving configuration

AssigneeInternational Business Machines Corporation

InventorDuixan Liu

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Abstract

The boxed-in slot antenna is provided with a conductive box, functioning as a waveguide, which is configured substantially parallel to the ground plane in which the slot is formed, thereby providing significant space savings relative to prior art designs wherein the box is positioned perpendicular to the conductive ground plane. The inventive antenna can be easily constructed using printed circuit board technology, by forming the ground plane as a coating on one side of a printed circuit board substrate, forming the main conductive plane of the conductive box structure on the other side of the printed circuit board, and interconnecting the two using plated through holes (that is, vias). The folded structure of the conductive box of the present invention makes it particularly suited for space-critical applications, such as may be found in laptop computers and other portable and handheld electronic devices, which it is desired to interconnect with a wireless local area network (wireless LAN).

Claims22

Dependent claims

In a boxed-in slot antenna for radiation having a free-space wavelength λ, a waveguide wavelength λg, and an electric half-wavelength λe/2, said antenna having:

(a) a conductive ground plane having a slot formed therein, said slot having a length L at least substantially equal to said electric half wavelength, said slot also having a width w which is less than said length L, said slot further having a longitudinal axis and first and second longitudinal edges;
and
(b) a conductive box structure which is conductively secured to said conductive ground plane and which is configured to cause said slot antenna to radiate from only a single side of said conductive ground plane;
the improvement comprising:
a folded, space-saving configuration for said conductive box structure, said conductive box structure in turn comprising:
(b-1) a main conductive plane which is substantially parallel to said ground plane and which is spaced a distance d therefrom, said distance d being substantially less than one-quarter of said waveguide wavelength λg;
(b-2) first and second conductive structures which are substantially parallel to each other and which are spaced apart a distance g which is at least substantially equal to L, said first and second conductive structures being substantially perpendicular to said conductive ground plane and said main conductive plane and also being substantially perpendicular to said longitudinal axis of said slot;
and
(b-3) third and fourth conductive structures which are substantially parallel to each other and which are spaced apart a distance a, said third and fourth conductive structures being substantially perpendicular to said conductive ground plane and said main conductive plane and also being substantially parallel to said longitudinal axis of said slot;
wherein:
said first, second, third and fourth conductive structures form conductive paths between said conductive ground plane and said main conductive plane;
and
when viewed in plan, said first, second, third and fourth conductive structures bound said slot;
whereby:
said folded, space-saving configuration for said conductive box structure is formed.

12 more elements

A boxed-in slot antenna for radiation having a free-space wavelength λ, a waveguide wavelength λg, and an electric half-wavelength λe/2, said antenna comprising:

(a) a conductive ground plane having a slot formed therein, said slot having a length L at least substantially equal to said electric half wavelength, said slot also having a width w which is less than said length L, said slot further having a longitudinal axis and first and second longitudinal edges;
and
(b) a conductive box structure, said conductive box structure in turn comprising:
(b-1) a main conductive plane which is substantially parallel to said ground plane and which is spaced a distance d therefrom, said distance d being substantially less than one-quarter of said waveguide wavelength λg;
(b-2) first and second conductive structures which are substantially parallel to each other and which are spaced apart a distance g which is at least substantially equal to L, said first and second conductive structures being substantially perpendicular to said conductive ground plane and said main conductive plane and also being substantially perpendicular to said longitudinal axis of said slot;
and
(b-3) third and fourth conductive structures which are substantially parallel to each other and which are spaced apart a distance a, said third and fourth conductive structures being substantially perpendicular to said conductive ground plane and said main conductive plane and also being substantially parallel to said longitudinal axis of said slot;
wherein:
said first, second, third and fourth conductive structures form conductive paths between said conductive ground plane and said main conductive plane;
and
when viewed in plan, said first, second, third and fourth conductive structures bound said slot.

8 more elements

Dependencies are inferred from the claim text.