COMMUNICATION APPARATUS

• US 20130017781A1
• Filed: 07/10/2012
• Published: 01/17/2013
• Est. Priority Date: 07/11/2011
• Status: Abandoned Application

• Current Assignee: Qualcomm technologies international, ltd. (Qualcomm, Inc.)
• Original Assignee: Cambridge Silicon Radio Limited (Qualcomm, Inc.)
• Inventors: Jones, Steve
• Application Number:
  US13/545,642
• Publication Number:
  US 20130017781A1
• Time in Patent Office: Days
• US Class Current: 455/41.1
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 5/335 at the feed, e.g. for impedance matching
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

A communication apparatus (10) has an antenna (12) suitable for transmitting and receiving signals in a near-field communication (NFC) frequency band. A resonant network is connected to the antenna (12), which is configured to adjust a self resonant frequency of the antenna (12) such that a signal in an FM frequency band may be transmitted or received by the antenna (12). An integrated circuit may be provided with the communication apparatus (10).

Claims

1. A communication apparatus comprising:

an antenna configured to transmit and receive signals in a near-field communication (NFC) frequency band; and

a resonant network connected to the antenna at a point intermediate ends of the antenna, such that the apparatus is able to use the antenna to transmit or receive a signal in an FM frequency band.

2. An apparatus according to claim 1, wherein the resonant network is connected to the antenna at its common mode point.

3. An apparatus according to claim 1, wherein the resonant network is connected to the antenna at points equidistant from the common mode point of the antenna.

4. An apparatus according to claim 3, wherein the resonant network is connected to the antenna at points midway between the common mode point and the ends of the antenna.

5. An apparatus according to claim 1, wherein the self-resonant frequency of the portion of the antenna used to receive or transmit a signal in an FM frequency band is greater than the self-resonant frequency of the portion of the antenna used to receive or transmit a signal in a near-field communication frequency band.

6. An apparatus according to claim 1, wherein, when the antenna is used for transmitting and/or receiving signals in a frequency modulated (FM) radio frequency band, the antenna has a self-resonant frequency (SRF) of greater than 150 MHz.

7. An apparatus according to claim 1, wherein, when the antenna is used for transmitting signals in a frequency modulated (FM) radio frequency band, the resonant network is arranged to exhibit series resonance.

8. An apparatus according to claim 1, wherein, when the antenna is used for receiving signals in a frequency modulated (FM) radio frequency band, the resonant network is arranged to exhibit parallel resonance.

9. An apparatus according to claim 1, wherein the resonant network comprises one or more capacitors, one or more of which is capable of being used to tune the frequency at which signals can be transmitted and received in the FM frequency band.

10. An apparatus according to claim 1, wherein the resonant network comprises one or more switches for allowing a selection to be made between transmitting and receiving signals in a frequency modulated (FM) radio frequency band.

11. An apparatus according to claim 1, wherein the resonant network is connected to the antenna in a single-ended mode.

12. An apparatus according to claim 1, wherein the signals in an NFC frequency band are transmitted and received via a differential input/output.

18. An integrated circuit comprising the apparatus of claim 1.

13. A communication apparatus comprising:

an antenna;

a first transmitter/receiver for transmitting and receiving signals, said first transmitter/receiver being connected to the antenna in a differential mode; and

a second transmitter/receiver for transmitting and receiving signals, said second transmitter/receiver being connected to the antenna in a single-ended mode.

14. A communication apparatus according to claim 13, wherein the first transmitter/receiver is arranged to transmit and receive signals in a near-field communication (NFC) frequency band.

15. A communication apparatus according to claim 13, wherein the second transmitter/receiver is arranged to transmit and receive signals in an FM frequency band.

16. A communication apparatus according to claim 13, wherein the second transmitter/receiver is connected to the antenna at its common mode point.

17. A communication apparatus according to claim 13, wherein the second transmitter/receiver is a resonant network.