Multiprotocol antenna for wireless systems
View Patent ↗First, second and third feed ports interface to an antenna that has an impedance disposed between its ends which are defined by the first and second feed ports. The third feed port interfaces to the antenna at an intermediate point between the ends. In a first mode (balanced mode) the impedance enables signals to/from the first and second feed ports to resonate along the whole of the antenna, and in a second mode the impedance enables signals to/from the third feed port to resonate along a portion of the antenna, the portion terminating at the impedance. In embodiments, the first mode is for RFID signals and the second mode is for any one or more of Bluetooth/WLAN/GPS/FM signals. The first and second mode may operate simultaneously. Also detailed is a method for making an electronic device having such an antenna.
1. An apparatus comprising:
an antenna;
a first feed port defining a first end of the antenna and a second feed port defining a second end of the antenna;
a third feed port that interfaces to the antenna at an intermediate point between the first and second ends;
an impedance disposed along the antenna and configured such that in a first mode signals to or from the first and second feed ports resonate along the whole of the antenna and in a second mode signals to or from the third feed port resonate along a portion of the antenna, said portion terminating at the impedance;
and in which the signals in the first mode comprise signals in a first frequency band, and the signals in the second mode comprise signals in a second frequency band and signals in a third frequency band;
wherein:
the impedance comprises a first impedance and a second impedance arranged serially along the antenna;
the first impedance is configured to pass signals in the first and second frequency bands and to block signals in the third frequency band from reaching the second impedance; and
the second impedance is configured to pass signals in the first frequency band and to block signals in the third frequency band.
2. The apparatus according to claim 1 , wherein the signals in the first mode comprise near field signals having an average range of less than one meter and the signals in the second mode comprise far field signals having an average range of at least five meters.
3. The apparatus according to claim 2 , wherein the near field signals comprise radio-frequency identification RFID signals and the far field signals comprise at least one of frequency modulation FM radio signals, global positioning system GPS signals, Bluetooth signals, and wireless local area network WLAN signals.
4. The apparatus according to claim 1 , in which the antenna is configured to operate in the first mode and in the second mode simultaneously.
5. The apparatus according to claim 1 , wherein the antenna operates in the first mode as a balanced antenna and the antenna operates in the second mode as an unbalanced antenna.
6. The apparatus according to claim 1 , further comprising a radio frequency identification RFID radio operatively coupled to the antenna via the first and second feed ports and no other radios operatively coupled to the antenna via the first or second feed ports, and a plurality of non-RFID radios operatively coupled to the antenna via the third feed port.
7. The apparatus according to claim 1 , wherein the impedance comprises one of a band pass filter or a low pass filter configured to pass signals in the first mode and to block signals in the second mode.
8. The apparatus according to claim 1 , wherein the first impedance comprises an LC tank circuit.
9. The apparatus according to claim 8 , wherein the second impedance comprises an inductor.
10. The apparatus according to claim 1 , wherein the first frequency band is a radio-frequency identification RFID band, the second frequency band is a frequency modulation FM band, and the third frequency band is selected from at least one of a Bluetooth band, a wireless local area network band, and a global positioning system band.
11. The apparatus according to claim 1 , disposed within a wireless handset device which further comprises:
a radio-frequency identification RFID radio operatively coupled to the antenna via the first feed port and the second feed port;
at least one of a frequency modulation FM radio, a Bluetooth radio, a wireless local area network WLAN radio and a global positioning system GPS radio operatively coupled to the antenna via the third feed port; and
a cellular radio operatively coupled to a cellular antenna that is separate from the antenna.
12. A wireless handset device comprising the apparatus according to claim 1 .
13. A method comprising:
operatively coupling a first radio, configured to operate in a first frequency band, to an antenna via a first feed port and a second feed port that define respective first and second ends of the antenna;
operatively coupling at least a second radio, configured to operate in a second frequency band, to the antenna via a third feed port that interfaces to the antenna at an intermediate point between the ends;
operatively coupling a third radio, configured to operate in a third frequency band, to the antenna via the third feed port, in which no radio apart from the first radio is operatively coupled to the antenna via both the first and the second feed ports, and there are a plurality of radios that are operatively coupled to the antenna via the third feed port;
wherein the antenna comprises an impedance disposed along the antenna between the third feed port and the first feed port, said impedance configured to pass signals within the first frequency band and to block signals within the second frequency band;
in which:
the said impedance comprises a first impedance and the antenna further comprises a second impedance arranged along the antenna serially with the first impedance between the first impedance and the third feed port;
the first impedance is configured to pass signals in the first frequency band and to block signals in the second frequency band; and
the second impedance is configured to pass signals in the first frequency band and to block signals in the third frequency band from reaching the second impedance.
14. The method according to claim 13 , wherein the first radio comprises a radio-frequency identification RFID radio and the second radio is selected from the group consisting of frequency modulation FM radio, global positioning system GPS radio, Bluetooth radio, and wireless local area network WLAN radio.
15. The method according to claim 13 , wherein the first radio is a radio-frequency RFID radio, the second radio is selected from at least one of a Bluetooth radio, a wireless local area network WLAN radio, and a global positioning system GPS radio; and the second radio is selected from at least one of a frequency modulation FM receiver and a frequency modulation FM transmitter.
16. The method according to claim 13 , wherein the impedance comprises an LC tank circuit.
17. The method according to claim 13 , the method further comprising operatively coupling a cellular radio to a cellular antenna separate from the antenna and disposing the first radio, the second radio, the cellular radio, the antenna with the impedance, and the cellular antenna within a mobile handset housing.