Antenna for a hearing assistance device
A hearing assistance device including a housing component ( 12 ) including a transceiver ( 68 ) and processing circuitry arranged in a compact block structure ( 50 ), a small feed loop ( 40 ) mounted on the compact block structure ( 50 ) and electrically connected to the transceiver ( 68 ), and an antenna element ( 30, 80 ) contained within a housing component ( 12 ). The small feed loop ( 40 ) and the antenna element ( 30, 80 ) are provided as metallic band elements, and the band elements in an area of electromagnetic coupling are arranged in substantially parallel planes.
1. A hearing assistance device comprising:
a housing component including a transceiver and processing circuitry arranged in a compact block structure;
a small feed loop mounted on the compact block structure and electrically connected to the transceiver, the small feed loop having a circumference between 5% and 20% of a wavelength of operation;
an antenna element contained within a housing component;
wherein both the small feed loop and the antenna element are provided as metallic band elements, and wherein the band elements in an area of electromagnetic coupling are arranged in substantially parallel planes.
2. The hearing assistance device according to claim 1 , wherein the band elements are arranged in a common plane.
3. The hearing assistance device according to claim 1 , wherein the small feed loop is a small loop.
4. The hearing assistance device according to claim 1 , wherein antenna element is contained adjacent to the top wall of the housing component.
5. The device of claim 1 , wherein the small feed loop has a circumference significantly below an intended wavelength of operation.
6. The device of claim 5 , wherein the small feed loop during operation has a substantially constant current distribution along the loop.
7. The device of claim 1 , wherein the antenna element is configured as a folded loop antenna.
8. The device of claim 1 , wherein the antenna element is configured as a folded dipole antenna.
9. The device of claim 8 , wherein the metallic pattern is provided on the inner surface of the housing component.
10. The device of claim 1 , wherein the antenna element is manufactured by adding a metallic pattern to the housing component in a Laser Direct Structuring (LDS) process.
11. The device of claim 1 , wherein the transceiver and processing circuitry are arranged in a compact block structure with at least a part of the small feed loop facing towards the housing component.
12. The device of claim 1 , wherein the antenna element is coupled to the feed element via mutual induction.
13. The device of claim 1 , wherein the coupling portions of the antenna element and the small feed loop are arranged in two parallel planes close to each other but separated by a dielectric.
14. The device of claim 13 , wherein said dielectric is air.
15. The device of claim 13 , wherein said dielectric is a solid dielectric material.