Audio device
An audio device (e.g., hearing aid) can optionally have a radio-frequency antenna that includes an antenna structure on a flexible printed circuit board. The antenna structure can have one or metal traces disposed on the flexible printed circuit board, the antenna structure extending over an area that substantially coincides with the area of the flexible printed circuit board. The flexible printed circuit board is foldable into a three-dimensional structure that can be disposed in a folded configuration in an audio device (e.g., hearing aid).
1. An audio device, comprising:
an outer casing configured to be worn proximate a human ear; and
an antenna housed in the outer casing, comprising
a flexible printed circuit board including one or more layers extending along an area in a two-dimensional plane;
an antenna structure comprising one or metal traces disposed on at least one of the layers of the flexible printed circuit board, the one or more metal traces including a plurality of repeating cell elements connected in series with each other, the one or more metal traces defining a plurality of rows connected in series and arranged parallel to each other on the flexible printed circuit board along an entire length of the rows so that an effect of a current flowing in one row is canceled by the current flowing in an adjacent row to achieve destructive interference between the rows, the antenna structure extending over the area of the flexible printed circuit board so that at least a portion of the one or more metal traces is adjacent a perimeter boundary of the flexible printed circuit board, irrespective of the shape of the area of the flexible printed circuit board,
wherein the flexible printed board is foldable into a three-dimensional structure configured to conform with a shape of the outer casing, the repeating cell elements to reduce a loading effect on the antenna when the outer casing is placed in proximity to a human head.
2. The device of claim 1 , wherein each of the repeating cell elements has one of an L-shape, an inverted L-shape, a Z-shape and a U-shape.
3. The device of claim 2 , wherein each of repeating cell elements has a U-shape, where adjacent cell elements are oriented in opposite directions.
4. The device of claim 1 , wherein the audio device is a hearing aid.
5. A radio-frequency antenna for an audio device, comprising:
a flexible printed circuit board including one or more layers extending along an area in a two-dimensional plane;
an antenna structure comprising one or metal traces disposed on at least one of the layers of the flexible printed circuit board, the antenna structure extending over an area that substantially coincides with the area of the flexible printed circuit board, the one or more metal traces including a plurality of repeating cell elements connected in series with each other, the one or more metal traces defining a plurality of rows connected in series and arranged parallel to each other on the flexible printed circuit board along an entire length of the rows so that an effect of a current flowing in one row is canceled by the current flowing in an adjacent row to achieve destructive interference between the rows to reduce a loading effect on the antenna when placed in proximity to a human head,
wherein the flexible printed board is foldable into a three-dimensional structure configured to be disposed in a folded configuration in an audio device.
6. The antenna of claim 5 , wherein the plurality of repeating cell elements have the same shape, size and orientation.
7. The antenna of claim 6 , wherein each of the repeating cell elements has one of an L-shape and an inverted L-shape.
8. The antenna of claim 6 , wherein each of the repeating cell elements has a Z-shape.
9. The antenna of claim 5 , wherein each of repeating cell elements has a U-shape, where adjacent cell elements are oriented in opposite directions.
10. The antenna of claim 5 , wherein a length of the one or more metal traces is trimmable by cutting one or more of the plurality of repeating cell elements to thereby optimize the operation of the antenna structure.
11. The antenna of claim 5 , wherein the plurality of repeating cell elements define a non-fractal antenna structure.
12. The antenna of claim 5 , wherein the antenna structure is configured to generate an effective radiation pattern substantially similar to that of an electrically short dipole antenna.
13. The antenna of claim 5 , wherein an overall length of the one or more metal traces that include the plurality of repeating cell elements achieves a desired impedance matching at a pair of terminals of the antenna structure to maximize power transfer with the antenna structure.
14. A radio-frequency antenna for an audio device, comprising:
a flexible printed circuit board including one or more layers extending along an area in a two-dimensional plane;
an antenna structure comprising one or metal traces disposed on at least one of the layers of the flexible printed circuit board, the one or more metal traces arranged in a non-fractal pattern comprising a plurality of repeating cell elements connected in series with each other, the one or more metal traces defining a plurality of rows connected in series and arranged parallel to each other on the flexible printed circuit board along an entire length of the rows so that an effect of a current flowing in one row is canceled by the current flowing in an adjacent row to achieve destructive interference between the rows to reduce a loading effect on the antenna when placed in proximity to a human head, the antenna structure extending across the area of the flexible printed circuit board so that at least a portion of the one or more metal traces is adjacent a boundary of the flexible printed circuit board along a perimeter of the flexible printed circuit board, irrespective of the shape of the area of the flexible printed circuit board,
wherein the flexible printed board is foldable into a three-dimensional structure configured to be disposed in a folded configuration in an audio device.
15. The antenna of claim 14 , wherein the plurality of repeating cell elements have the same shape, size and orientation.
16. The antenna of claim 15 , wherein each of the repeating cell elements has one of an L-shape, an inverted L-shape and a Z-shape.
17. The antenna of claim 14 , wherein each of repeating cell elements has a U-shape, where adjacent cell elements are oriented in opposite directions.
18. The antenna of claim 14 , wherein a length of the one or more metal traces is trimmable by cutting one or more of the plurality of repeating cell elements to thereby optimize the operation of the antenna structure.