Hearing assistance device incorporating a quarter wave stub as a solderless antenna connection
A hearing assistance device for use by a wearer comprises an enclosure and a substrate comprising a circuit board disposed in the enclosure. An antenna is disposed within or on the enclosure. A feed arm arrangement is coupled to the circuit board. A section of the feed arm arrangement extends over the antenna and establishes a non-contacting electrical coupling with the antenna. The section of the feed arm arrangement extending over the antenna can have an electrical length of approximately one-quarter of a wavelength of a signal transmitted or received by the antenna.
1. A hearing assistance device for use by a wearer, comprising:
an enclosure that comprises a first wall and an opposing second wall;
a flexible substrate comprising a circuit board disposed in the enclosure, wherein the circuit board supports electronics of the hearing assistance device;
an antenna disposed within or on the enclosure, wherein:
the antenna comprises a first antenna element and a second antenna element, wherein the first antenna element is not physically connected to the second antenna element,
the first antenna element of the antenna is supported by or positioned proximate the first wall of the enclosure, and
the second antenna element of the antenna is supported by or positioned proximate the second wall of the enclosure; and
a feed arm arrangement coupled to and defining a continuous section of the circuit board, the feed arm arrangement comprising a first feed arm and a second feed arm, wherein:
the first feed arm comprises a first section that defines a first transmission line that extends over and establishes a first non-contacting electrical transmission line coupling with the first antenna element,
the first section of the first feed arm has an electrical length of approximately one-quarter of a wavelength of a signal transmitted or received by the antenna, and the first section of the first feed arm extending over the first antenna element transforms the first transmission line from an open circuit over the first antenna element to a short circuit at an input of the first antenna element,
the second feed arm comprises a second section that defines a second transmission line that extends over and establishes a second non-contacting electrical transmission line coupling with the second antenna element, and
the second section of the second feed arm has an electrical length of approximately one-quarter of the wavelength of the signal transmitted or received by the antenna, and the second section of the second feed arm extending over the second antenna element transforms the second transmission line from an open circuit over the second antenna element to a short circuit at an input of the second antenna element.
2. The hearing assistance device of claim 1 , wherein:
the first transmission line comprises a first radial stub, and
the second transmission line comprises a second radial stub.
3. The hearing assistance device of claim 1 , wherein:
the first antenna element has a perimeter;
the first transmission line comprises a first location and a second location;
the first location of the first transmission line is in alignment with the perimeter; and
the second location of the first transmission line is situated within the first antenna element.
4. The hearing assistance device of claim 1 , wherein the antenna defines a Laser Direct Structuring (LDS) structure disposed on the enclosure.
5. The hearing assistance device of claim 1 , wherein:
the first antenna element defines a first printed structure disposed on the first wall of the enclosure; and
the second antenna element defines a second printed structure disposed on the second wall of the enclosure.
6. The hearing assistance device of claim 1 , wherein the antenna comprises a stamped metal antenna or a flex circuit antenna.
7. The hearing assistance device of claim 1 , wherein:
a spine is disposed in the enclosure; and
the antenna is disposed on or supported by the spine.
8. The hearing assistance device of claim 1 , further comprising at least one of:
a first insulator material disposed between the first section of the first feed arm and the first antenna element, or
a second insulator material disposed between the second section of the second feed arm and the second antenna element.
9. The hearing assistance device of claim 1 , wherein the first non-contacting electrical transmission line coupling and the second non-contacting electrical transmission line coupling are solderless couplings.