Antennas for hearing aids
An antenna configured in a hybrid circuit provides a compact design for a hearing aid to communicate wirelessly with a system external to the hearing aid. In an embodiment, an antenna includes metallic traces in a hybrid circuit that is configured for use in a hearing aid. The antenna includes contacts in the hybrid circuit to couple the metallic traces to electronic devices in the hybrid circuit. In an embodiment, the metallic traces form a planar coil design having a number of turns of the coil in a substrate in the hybrid circuit. In another embodiment, the metallic traces are included in a flex circuit on a substrate in the hybrid circuit. An antenna configured in a hybrid circuit allows for use in a completely-in-the-canal hearing aid.
1. A hearing aid comprising:
a hybrid circuit including a first substrate and a second substrate;
an antenna having metallic traces disposed in the hybrid circuit, wherein the antenna includes at least one turn on the first substrate and at least one turn on the second substrate;
an electronic device in the hybrid circuit coupled to the metallic traces of the antenna; and
a signal processing unit to process information received and transmitted by the antenna, wherein the antenna is configured with a first turn to act as a transmitting antenna and a second turn outside the first turn to act as a receiving antenna, the second turn configured to inductively receive signals from the first turn for measurement of power in the first turn.
2. The hearing aid of claim 1 , wherein the hearing aid includes a conductive line aligned along the antenna, the conductive line configured to measure the power in the antenna.
3. The hearing aid of claim 2 , wherein the conductive line and the antenna are configured as inductively coupled loops.
4. The hearing aid of claim 1 , further including an RF drive circuit coupled between the signal processing unit and the antenna.
5. The hearing aid of claim 1 , wherein the electronic device includes a matching circuit coupled to the antenna, the matching circuit having an impedance that is substantially the complex conjugate of an impedance of the antenna to which it is coupled.
6. The hearing aid of claim 1 , wherein the electronic device includes a capacitance network coupled to the antenna, the capacitance network configured to selectively couple a capacitance in parallel with the antenna.
7. The hearing aid of claim 1 , wherein the electronic device includes a capacitance network coupled to the antenna, the capacitance network configured to selectively couple a capacitance in series with the antenna.
8. The hearing aid of claim 1 , wherein the electronic device includes a capacitance network coupled to the antenna, the capacitance network configured to selectively couple a capacitance in parallel with the antenna and a capacitance in series with the antenna.
9. The hearing aid of claim 1 , wherein the metallic traces of the antenna are configured as a number turns in a polyimide substrate.
10. The hearing aid of claim 1 , wherein the metallic traces of the antenna are configured as a number turns in a low temperature cofired ceramic substrate.
11. The hearing aid of claim 1 , wherein the metallic traces of the antenna are configured as a number turns in a quartz ceramic substrate.
12. The hearing aid of claim 1 , wherein the antenna includes a flex circuit.
13. The hearing aid of claim 12 , wherein the flex circuit includes flexible metallic traces in a polyimide layer.
14. The hearing aid of claim 1 , wherein the metallic traces of the antenna have a width and a combined length to provide a selected operating distance for a selected input power.
15. The hearing aid of claim 14 , wherein the selected operating distance for a selected input power ranges from about 2 meters to about 3 meters for an input power ranging from about −10 dBm to about −20 dBm.
16. The hearing aid of claim 1 , wherein the antenna is configured to operate with a carrier frequency ranging from about 400 MHz to about 3000 MHz.
17. A hearing aid comprising:
a housing;
an electronic circuit within the housing; and
an antenna coupled to an electronic device within the housing, the antenna configured as a number of turns on a first and a second dielectric substrate of a hybrid circuit to provide wireless communication to the electronic circuit from a source exterior to the hearing aid, wherein the antenna is configured with a first turn on the first dielectric substrate to act as a transmitting antenna and a second turn outside the first turn, the second turn on the second dielectric substrate configured to inductively receive signals from the first turn for measurement of power in the first turn.
18. The hearing aid of claim 17 , wherein the hearing aid includes a conductive line aligned along the antenna, the conductive line configured to measure the power in the antenna.
19. The hearing aid of claim 17 , wherein the antenna is a 12 turn helix antenna.
20. The hearing aid of claim 17 , wherein the antenna has a working distance of about 10 meters.