Apparatus, method and computer program for wireless communication
An apparatus including: a first antenna operable in a first resonant frequency band; a second antenna operable in a second resonant frequency band; a first filter coupled to the second antenna; and a first phase shifter configured to provide the combination of at least the first filter and the second antenna with an impedance at the first resonant frequency band which substantially suppresses coupling between the first antenna and the second antenna.
1. An apparatus comprising:
a first antenna configured to operate in a first resonant frequency band;
a second antenna configured to operate in a second resonant frequency band;
a first filter coupled to the second antenna; and
a first phase shifter configured to provide the combination of at least the first filter and the second antenna with an impedance at the first resonant frequency band which substantially suppresses coupling between the first antenna and the second antenna.
2. An apparatus as claimed in claim 1 , wherein the combination of the first filter and the second antenna are configured to form a notch filter having a resonant frequency band, the first phase shifter being configured to shift the resonant frequency band of the combination to be substantially equal to the first resonant frequency band.
3. An apparatus as claimed in claim 1 , wherein the first phase shifter is variable and is configurable to provide the combination of the first filter and the second antenna with an impedance at a resonant frequency band, selectable from a plurality of resonant frequency bands, which substantially suppresses coupling between the first antenna and the second antenna.
4. An apparatus as claimed in claim 3 , further comprising a controller configured to control the first phase shifter and/or the second phase shifter and to select the resonant frequency band at which coupling between the first antenna and the second antenna, and/or the first antenna and the third antenna respectively is substantially suppressed.
5. An apparatus as claimed in claim 1 , further comprising a third antenna configured to operate at a third resonant frequency band, a second filter coupled to the third antenna and a second phase shifter configured to provide the combination of at least the second filter and the third antenna with an impedance at the first resonant frequency band which substantially suppresses coupling between the first antenna and the third antenna.
6. An apparatus as claimed in claim 5 , wherein the combination of the second filter and the third antenna are configured to form a notch filter having a resonant frequency band, the second phase shifter being configured to shift the resonant frequency band of the combination to be substantially equal to the first resonant frequency band.
7. An apparatus as claimed in claim 5 , wherein the second phase shifter is variable and is configurable to provide the combination of the second filter and the third antenna with an impedance at a resonant frequency band, selectable from a plurality of resonant frequency bands, which substantially suppresses coupling between the first antenna and the third antenna.
8. An apparatus as claimed in claim 5 , further comprising a multiplexer including the first filter and the second filter.
9. An apparatus as claimed in claim 5 , wherein the second filter is a high pass filter.
10. An apparatus as claimed in claim 1 , wherein the first filter is a low pass filter.
11. An apparatus as claimed in any of the preceding claim 1 , wherein the first phase shifter is integral with the first filter.
12. An apparatus as claimed in claim 1 , wherein the first resonant frequency band is a Global Navigation Satellite System (GNSS) frequency band.
13. An electronic device comprising an apparatus as claimed in claim 1 .
14. A method comprising:
providing a first antenna configured to operate in a first resonant frequency band, a second antenna configured to operate in a second resonant frequency band, a first filter coupled to the second antenna, and a first phase shifter; and
configuring the first phase shifter to provide the combination of at least the first filter and the second antenna with an impedance at the first resonant frequency band which substantially suppresses coupling between the first antenna and the second antenna.
15. A method as claimed in claim 14 , further comprising configuring the combination of the first filter and the second antenna to form a notch filter having a resonant frequency band, the first phase shifter being configured to shift the resonant frequency band of the combination to be substantially equal to the first resonant frequency band.
16. A method as claimed in claim 14 , wherein the first phase shifter is variable and the method further comprises configuring the first phase shifter to provide the combination of the first filter and the second antenna with an impedance at a resonant frequency band, selectable from a plurality of resonant frequency bands, which substantially suppresses coupling between the first antenna and the second antenna.
17. A method as claimed in claim 14 , further comprising providing a third antenna configured to operate at a third resonant frequency band, a second filter coupled to the third antenna and a second phase shifter; and configuring the second phase shifter to provide the combination of at least the second filter and the third antenna with an impedance at the first resonant frequency band which substantially suppresses coupling between the first antenna and the third antenna.
18. A method as claimed in claim 17 , further comprising configuring the combination of the second filter and the third antenna to form a notch filter having a resonant frequency band, the second phase shifter being configured to shift the resonant frequency band of the combination to be substantially equal to the first resonant frequency band.
19. A non-transitory computer-readable storage medium encoded with instructions that, when executed by a processor, perform: controlling a first phase shifter to provide a combination of a first filter and a second antenna, coupled to the first filter, with an impedance at a resonant frequency band, selectable from a plurality of resonant frequency bands, which substantially suppresses coupling between a first antenna and the second antenna.
20. A non-transitory computer-readable storage medium as claimed in claim 19 , wherein the first antenna is configured to operate in a first resonant frequency band and the method includes controlling the first phase shifter to provide the combination of the first filter and the second antenna with an impedance at the first resonant frequency band which substantially suppresses coupling between the first antenna and the second antenna.