CIRCUIT, TRANSMISSION SYSTEM AND METHOD FOR DETERMINING PROXIMITY OF AN OBJECT

• US 20150234077A1
• Filed: 01/12/2015
• Published: 08/20/2015
• Est. Priority Date: 02/14/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Lahti, Saku, Komulainen, Mikko S.
• Granted Patent: US 9,864,087 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01V 3/08 operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices with electromagnetic waves G01V3/12
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: H04B 1/3838 Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile

Abstract

A circuit includes a sensing circuit for a first antenna and a second antenna, the sensing circuit including an adjustable characteristic that is based on a proximity of an object to the first or second antenna used to transmit a transmit signal. An evaluation circuit is coupled to the sensing circuit. The evaluation circuit is configured to monitor the characteristic of the sensing circuit and to determine whether the characteristic fulfills a predetermined criterion.

Claims

1. A circuit, comprising:

a sensing circuit for a first antenna and a second antenna, wherein the sensing circuit comprises an adjustable characteristic that is based on a proximity of an object to the first or second antenna used to transmit a transmit signal; and

an evaluation circuit coupled to the sensing circuit, the evaluation circuit being configured to monitor the characteristic of the sensing circuit and to determine whether the characteristic fulfills a predetermined criterion.

2. The circuit of claim 1, wherein the sensing circuit comprises the first antenna or the second antenna.

3. The circuit of claim 2, wherein the sensing circuit comprises the first antenna if the first antenna is used to transmit the signal or wherein the sensing circuit comprises the second antenna if the second antenna is used to transmit the signal.

4. The circuit of claim 2, further comprising:

a switching element configured to couple the evaluation circuit to the first antenna at a first time instant and to couple the evaluation circuit to the second antenna at a second time instant.

5. The circuit of claim 4, wherein the switching element alternatingly couples the evaluation circuit to the first antenna and to the second antenna.

6. The circuit of claim 1, further comprising a transmitter configured to generate the transmit signal to be transmitted by the first antenna or by the second antenna.

7. The circuit of claim 6, wherein the transmitter is configured to reduce a power of the transmit signal if the characteristic fulfills the predetermined criterion.

8. The circuit of claim 6, further comprising a signal switching element configured to couple the transmitter to the first antenna or to the second antenna, wherein the evaluation circuit is coupled to the transmitter.

9. The circuit of claim 1, wherein the sensing circuit comprises a sensing electrode coupled to the evaluation circuit, the sensing electrode being arranged between the first antenna and the second antenna.

10. The circuit of claim 9, wherein the sensing electrode comprises an antenna configured to receive a first receive signal, the first receive signal being different than the receive signals received by the first antenna and by the second antenna.

11. The circuit of claim 1, wherein the evaluation circuit generates a proximity signal indicating the presence of an object in a vicinity of the first antenna or the second antenna if the characteristic fulfills the predetermined criterion.

12. The circuit of claim 1, wherein the evaluation circuit monitors a capacitance between an element of the sensing circuit and a reference potential.

13. The circuit of claim 1, wherein the predetermined criterion corresponds to an acceptable absorption of electromagnetic energy by the object.

14. Transmission system, comprising:

a first antenna operable to transmit a signal;

a second antenna operable to transmit the signal; and

a circuit according to claim 1.

15. The transmission system of claim 14, further comprising a transmitter to generate the transmit signal to be transmitted by the first antenna or by the second antenna.

16. The transmission system of claim 15, wherein the transmitter is configured to transmit the transmit signal using the first antenna or the second antenna;

and wherein a first receive signal is received using the first antenna and a second receive signal is received using the second antenna.

17. The transmission system of claim 14, wherein the first antenna and the second antenna are configured to transmit a wireless Ian signal or a mobile telecommunication signal.

18. A method for determining proximity of an object to a first antenna or to a second antenna usable to transmit a transmit signal, comprising:

monitoring a characteristic of a sensing circuit, the sensing circuit comprising an adjustable characteristic that is based on a proximity of an object to the first or second antenna used to transmit a transmit signal; and

indicating an object in the proximity of the first or second antenna if the characteristic fulfills a predetermined criterion.

19. The method of claim 18, further comprising:

determining if the antenna used to transmit the transmit signal has changed.

20. The method of claim 19, further comprising:

including the antenna used to transmit the transmit signal into the sensing circuit if the antenna used to transmit the transmit signal has changed.