Inverted F-shaped antenna for hearing instruments
An antenna for a hearing instrument comprises an antenna element that is fed at an intermediate point between a first end of the antenna element and a second end of the antenna element. The antenna element has a J-shaped surface. The antenna also includes a ground plane element, a dielectric structure, and a shorting structure. The ground plane element that has a first segment and a second segment. A surface of the first segment has substantially the same shape as the J-shaped surface of the antenna element. The second segment connects a first end of the first segment to a second end of the first segment, thereby defining an opening through the ground plane element. The dielectric structure is disposed between the antenna element and the ground plane element. The shorting structure connects the first end of the antenna element to the ground plane element.
1 . An antenna for a hearing instrument, the antenna comprising:
an antenna element that is fed at an intermediate point between a first end of the antenna element and a second end of the antenna element, wherein the antenna element has a J-shaped surface;
a ground plane element that has a first segment and a second segment, wherein:
a surface of the first segment has substantially the same shape as the J-shaped surface of the antenna element, and
the second segment connects a first end of the first segment to a second end of the first segment, thereby defining an opening through the ground plane element, wherein the first end of the first segment is aligned with the first end of the antenna element and the second end of the first segment is aligned with the second end of the antenna element;
a dielectric structure disposed between the antenna element and the ground plane element; and
a shorting structure that connects the first end of the antenna element to the ground plane element.
2 . The antenna of claim 1 , wherein a thickness of the antenna element is greater than a thickness of the ground plane element.
3 . The antenna of claim 1 , wherein an electrical length of the antenna element is approximately ¼ of a transmission wavelength of the antenna.
4 . The antenna of claim 1 , wherein a distance between the intermediate point and the shorting structure is selected to obtain 50 Ohm matching.
5 . The antenna of claim 1 , wherein an electric field direction of the antenna is primarily oriented from the ground plane element to the antenna element and normal to a head of a user when the hearing instrument is worn by the user.
6 . The antenna of claim 1 , wherein the shorting structure comprises one or more vias connecting the antenna element and the ground plane element.
7 . The antenna of claim 1 , wherein:
the J-shaped surface of the antenna element lies within a plane of the antenna element defined by a longitudinal axis and a lateral axis,
the longitudinal axis corresponds to a longer dimension of the antenna element and the lateral axis is perpendicular to the longitudinal axis,
a hook-shaped portion of the J-shaped surface deviates from an edge of a linear portion of the J-shaped surface along the lateral axis, and
the ground plane element is disposed in a plane parallel to the plane of the antenna element and displaced from the plane of the antenna element along an axis orthogonal to the longitudinal axis and the lateral axis.
8 . The antenna of claim 1 , wherein the first segment of the ground plane element and the second segment of the ground plane element are connected to each other.
9 . The antenna of claim 1 , wherein the antenna element comprises:
a first layer having a same thickness as the ground plane element; and
a second layer connected to the first layer, wherein the second layer increases a total thickness of the antenna element.
10 . The antenna of claim 1 , further comprising a removal handle that includes an electrically conductive element connected to a hook-shaped portion of the J-shaped surface of the antenna element, the electrically conductive element being adapted to shorten a size of the hook-shaped portion of the antenna element.
11 . The antenna of claim 1 , wherein the J-shaped surface of the antenna element includes a linear portion and a hook-shaped portion, the hook-shaped portion including a combination of curved and linear segments.
12 . A hearing instrument comprising an antenna that comprises:
an antenna element that is fed at an intermediate point between a first end of the antenna element and a second end of the antenna element, wherein the antenna element has a J-shaped surface;
a ground plane element that has a first segment and a second segment, wherein:
a surface of the first segment has substantially the same shape as the J-shaped surface of the antenna element, and
the second segment connects a first end of the first segment to a second end of the first segment, thereby defining an opening through the ground plane element, wherein the first end of the first segment is aligned with the first end of the antenna element and the second end of the first segment is aligned with the second end of the antenna element;
a dielectric structure disposed between the antenna element and the ground plane element; and
a shorting structure that connects the first end of the antenna element to the ground plane element.
13 . The hearing instrument of claim 12 , wherein a thickness of the antenna element is greater than a thickness of the ground plane element.
14 . The hearing instrument of claim 12 , wherein an electrical length of the antenna element is approximately ¼ of a transmission wavelength of the antenna.
15 . The hearing instrument of claim 12 , wherein a distance between the intermediate point and the shorting structure is selected to obtain 50 Ohm matching.
16 . The hearing instrument of claim 12 , wherein an electric field direction of the antenna is oriented from the ground plane element to the antenna element and normal to a head of a user when the hearing instrument is worn by the user.
17 . The hearing instrument of claim 12 , wherein the shorting structure comprises one or more vias connecting the antenna element and the ground plane element.
18 . The hearing instrument of claim 12 , wherein:
the J-shaped surface of the antenna element lies within a plane of the antenna element defined by a longitudinal axis and a lateral axis,
the longitudinal axis corresponds to a longer dimension of the antenna element and the lateral axis is perpendicular to the longitudinal axis,
a hook-shaped portion of the J-shaped surface deviates from an edge of a linear portion of the J-shaped surface along the lateral axis, and
the ground plane element is disposed in a plane parallel to the plane of the antenna element and displaced from the plane of the antenna element along an axis orthogonal to the longitudinal axis and the lateral axis.
19 . The hearing instrument of claim 12 , wherein the first segment of the ground plane element and the second segment of the ground plane element are connected to each other.
20 . The hearing instrument of claim 12 , wherein the antenna element comprises:
a first layer having a same thickness as the ground plane element; and
a second layer connected to the first layer, wherein the second layer increases a total thickness of the antenna element.
21 . The hearing instrument of claim 12 , further comprising:
a shell that defines an enclosure in which the antenna is positioned; and
a battery compartment door that provides access to a battery compartment of the hearing instrument, wherein the battery compartment is defined such that a battery is insertable into the battery compartment through the opening defined by the ground plane element.
22 . The hearing instrument of claim 12 , further comprising a removal handle that includes an electrically conductive element connected to a hook-shaped portion of the J-shaped surface of the antenna element.
23 . The hearing instrument of claim 12 , further comprising:
a shell that defines an enclosure in which the antenna is positioned; and
a faceplate that covers an opening of the shell, wherein no part of the antenna protrudes from the faceplate.
24 . The hearing instrument of claim 12 , further comprising:
a shell that defines an enclosure in which the antenna is positioned,
wherein when the hearing instrument is worn, a hook-shaped portion of the J-shaped surface of the antenna element is oriented toward a posterior side of a head of a user.