Small loop antenna with shorting conductors for hearing assistance devices
Disclosed herein, among other things, are methods and apparatus for mitigating antenna interference for hearing assistance devices. One aspect of the present subject matter includes a hearing aid for a wearer including hearing aid electronics and an antenna including a loop segment. According to various embodiments, one or more conductors are connected in parallel with a portion of the loop segment. The conductors electrically short the loop segment to change current distribution in the antenna. The conductors reduce unwanted coupling between the hearing aid electronics and the antenna, according to various embodiments.
1. A hearing aid for a wearer, comprising:
hearing aid electronics;
an antenna including multiple loop segments; and
a plurality of conductors, each of the conductors electrically connected in parallel with a selectable portion of at least one of the loop segments, at least one of the plurality of conductors electrically shorting at least one of the loop segments to adjust antenna impedance, antenna frequency response, and electric and magnetic field distribution including reducing radiation emissions of the antenna at out-of-band frequencies to reduce transmitter harmonic radiation by changing current distribution in the antenna by adjusting placement and size of the at least one of the plurality of conductors, wherein each of the multiple loop segments includes a different shorting conductor shape.
2. The hearing aid of claim 1 , wherein at least one of the one or more conductors is configured to reduce unwanted coupling between the hearing aid electronics and the antenna by changing current distribution in the antenna.
3. The hearing aid of claim 1 , wherein at least one of the one or more conductors is configured to adjust antenna frequency response by changing current distribution in the antenna.
4. The hearing aid of claim 1 , wherein at least one of the one or more conductors is configured to adjust antenna impedance by changing current distribution in the antenna.
5. The hearing aid of claim 1 , wherein at least one of the one or more conductors is configured to adjust electric field distribution by changing current distribution in the antenna.
6. The hearing aid of claim 1 , wherein at least two of the multiple loop segments include different shorting conductor configurations.
7. The hearing aid of claim 1 , wherein one or more conductors are configured in parallel with each of the multiple loop segments.
8. The hearing aid of claim 1 , wherein a width of the one of the one or more conductors is varied to adjust current flowing through the antenna.
9. The hearing aid of claim 1 , wherein at least one of the one or more conductors is curved.
10. The hearing aid of claim 1 , wherein at least one of the one or more conductors follows a split path.
11. A method for making an antenna for a hearing aid, the method comprising:
connecting each of a plurality of conductors electrically in parallel with a selectable portion of at least one segment of multiple loop segments of the antenna, including electrically shorting at least one of the loop segments to adjust antenna impedance, antenna frequency response, and electric and magnetic field distribution including reducing radiation emissions of the antenna at out- of-band frequencies to reduce transmitter harmonic radiation by changing current distribution in the antenna by adjusting placement and size of at least one of the plurality of conductors, wherein each of the multiple loop segments includes a different shorting conductor shape.
12. The method of claim 11 , wherein connecting the conductor is performed during manufacture of the antenna.
13. The method of claim 11 , wherein connecting the conductor is performed during assembly of the hearing assistance device.
14. The method of claim 11 , wherein the antenna includes a flex circuit.
15. The method of claim 11 , wherein the antenna includes a hybrid circuit.
16. The method of claim 11 , wherein the conductor includes a capacitively coupled finger.
17. The method of claim 11 , wherein connecting the conductor includes using a wire.
18. The method of claim 11 , wherein connecting the conductor includes using metal- on-plastics.
19. The method of claim 11 , wherein connecting the conductor includes using conductive printing.