Patch antenna integrated in a wristwatch
There is disclosed a wristwatch ( 21 ) including a middle part ( 22 ) defining a middle plane (Y), conductive means ( 35, 36 ) for attaching the wristband ( 32 ) to the middle part, a radio-frequency module ( 27 ) arranged inside the middle part and connected, on the one hand, to a ground plane and, on the other hand, to a radiating element, insulated from each other and forming an antenna. The ground plane includes at least one conductive surface portion ( 37 ) of the wristband connected to the wristband attaching means and the middle part which is conductive, the latter being connected from the inside to the radio-frequency module. The radiating element includes a first conductive surface element ( 25 ) arranged in a substantially parallel plane to the middle plane defined by the middle part.
1. A wristwatch including a middle part defining a middle plane, conductive means for attaching a wristband to the middle part, a radio-frequency module arranged inside the middle part and connected, on the one hand, to a ground plane and, on the other hand, to a radiating element, insulated from each other and forming an antenna, the ground plane including at least one conductive surface portion of the wristband connected to the wristband attaching means, wherein the ground plane further includes the middle part which is conductive, the latter being connected from the inside to the radio-frequency module and wherein the radiating element includes a first conductive surface element arranged in a substantially parallel plane to the middle plane defined by the middle part.
2. The wristwatch according to claim 1 , wherein the first conductive surface element is made by means of a metal back cover insulated from the middle part via a dielectric element.
3. The wristwatch according to claim 2 , wherein the dielectric element is formed by a malleable plastic gasket having a substantially temperature constant permittivity.
4. The wristwatch according to claim 2 , wherein the radiating element includes a second conductive surface element also arranged in a substantially parallel plane to the middle plane defined by the middle part and connected to the first surface element so as to define a radiating cylinder.
5. The wristwatch according to claim 4 , including a dial having a first face visible through a glass and a second, not visible, face, opposite the first face, wherein the second conductive surface element is made by means of a metal layer applied onto a part of the dial face that is not visible so as not to establish contact with the middle part, and wherein the uncovered part of the dial is formed by a dielectric material insulating the middle part from the second surface element.
6. The wristwatch according to claim 1 , the wristband including first and second strands, wherein conductive surface portion is formed by a flexible conductive plate overmoulded in one of the two wristband strands and connected to the middle part via the attaching means.
7. The wristwatch according to claim 6 , wherein the ground plane further includes a second flexible conductive plate overmoulded in the other wristband strand and also connected to the middle part via the attaching means.
8. The wristwatch according to claim 7 , wherein the attaching means include, for each wristband strand, two metal horns secured to the middle part between which is arranged a metal bar and wherein the conductive plate or plates are bent around the corresponding bar or bars.
9. The wristwatch according to claim 7 , wherein the attaching means include, for each wristband strand, two metal horns secured to the middle part and wherein the conductive plate or plates have a rigid bar-shaped end cooperating with the horns.