Remote compensators for mobile devices
Remote compensators for mobile devices are provided. In certain embodiments, a mobile device includes a cable-side circulator, an antenna, receive amplifier circuitry that amplifies a receive signal from the antenna and provides an amplified receive signal to the cable-side circulator, transmit amplifier circuitry that amplifies a transmit signal from the cable-side circulator, and a first antenna-side circulator and a second antenna-side circulator each coupled between the transmit amplifier circuitry and the antenna. The first antenna-side circulator and the second antenna-side circulator operate to compensate the receive signal for transmit leakage arising from the transmit amplifier circuitry.
1. A mobile device comprising:
a cable-side circulator including an output configured to provide a transmit signal and an input configured to receive an amplified receive signal;
an antenna;
receive amplifier circuitry configured to amplify a receive signal from the antenna and to provide the amplified receive signal to the cable-side circulator;
transmit amplifier circuitry including a power amplifier configured to amplify the transmit signal from the cable-side circulator; and
a first antenna-side circulator and a second antenna-side circulator connected in series with the power amplifier between the output of the cable-side circulator and the antenna, the first antenna-side circulator and the second antenna-side circulator configured to control the input of the cable-side circulator to compensate the amplified receive signal for transmit leakage arising from the transmit amplifier circuitry.
2. The mobile device of claim 1 wherein the transmit amplifier circuitry includes an input connected to the cable-side circulator and an output connected to the second antenna-side circulator, the first antenna-side circulator connected between the second antenna-side circulator and the antenna.
3. The mobile device of claim 2 further comprising a combiner configured to generate the receive signal at an output and coupled to the first antenna-side circulator at a first input, and a phase shifter coupled between the second antenna-side circulator and a second input of the combiner.
4. The mobile device of claim 1 further comprising a front-end system and a cable connecting the front-end system to the cable-side circulator, the cable configured to carry the transmit signal and the amplified receive signal.
5. A remote compensator for a mobile device, the remote compensator comprising:
a cable-side circulator coupled to a cable port, the cable-side circulator including an output configured to provide a transmit signal and an input configured to receive an amplified receive signal;
receive amplifier circuitry configured to amplify a receive signal from an antenna port to provide the amplified receive signal to the cable-side circulator;
transmit amplifier circuitry including a power amplifier configured to amplify the transmit signal from the cable-side circulator; and
a first antenna-side circulator and a second antenna-side circulator connected in series with the power amplifier between the output of the cable-side circulator and the antenna port, the first antenna-side circulator and the second antenna-side circulator configured to control the input of the cable-side circulator to compensate the amplified receive signal for transmit leakage arising from the transmit amplifier circuitry.
6. The remote compensator of claim 5 wherein the transmit amplifier circuitry includes an input connected to the cable-side circulator and an output connected to the second antenna-side circulator, the first antenna-side circulator connected between the second antenna-side circulator and the antenna port.
7. A method of remote compensation in a mobile device, the method comprising:
amplifying a receive signal from an antenna to generate an amplified receive signal using receive amplifier circuitry;
providing the amplified received signal from the receive amplifier circuitry to a cable by way of an input of a cable-side circulator;
amplifying a transmit signal from an output of the cable-side circulator using transmit amplifier circuitry including a power amplifier; and
compensating the receive signal for transmit leakage arising from the transmit amplifier circuitry using a first antenna-side circulator and a second antenna-side circulator connected in series with the power amplifier between the output of the cable-side circulator and the antenna, including controlling the input of the cable-side circulator using the first antenna-side circulator and the second antenna-side circulator.
8. The method of claim 7 wherein the second antenna-side circulator includes an input connected to an output of the power amplifier, a first output connected to an input of the first antenna-side circulator, and a second output connected to an input of a phase shifter, the method further comprising generating a phase-shifted radio frequency signal by phase shifting a first radio frequency signal from the second output of the second antenna-side circulator.
9. The method of claim 8 further comprising combining the phase-shifted radio frequency signal and a second radio frequency signal from an output of the first antenna-side circulator using a combiner.
10. The method of claim 9 further comprising providing a 180 degree phase shift using the phase shifter.
11. The mobile device of claim 1 further comprising an antennas-side multiplexer connected between the antenna and the first antenna-side circulator.
12. The mobile device of claim 1 wherein the second antenna-side circulator is directly connected between the first antenna-side circulator and an output of the power amplifier.
13. The mobile device of claim 1 further comprising a phase shifter, the second antenna-side circulator including an input connected to an output of the power amplifier, a first output connected to an input of the first antenna-side circulator, and a second output connected to an input of the phase shifter.
14. The mobile device of claim 13 wherein the first antenna-side circulator further includes a first output connected to the antenna.
15. The mobile device of claim 14 further comprising a combiner including a first input connected to an output of the phase shifter, a second input connected to a second output of the first antenna-side circulator, and an output connected to an input of the receive amplifier circuitry.
16. The mobile device of claim 15 wherein the phase shifter provides a 180 degree phase shift.
17. The remote compensator of claim 5 wherein the second antenna-side circulator is directly connected between the first antenna-side circulator and an output of the power amplifier.
18. The remote compensator of claim 5 further comprising a phase shifter, the second antenna-side circulator including an input connected to an output of the power amplifier, a first output connected to an input of the first antenna-side circulator, and a second output connected to an input of the phase shifter.
19. The remote compensator of claim 18 wherein the first antenna-side circulator further includes a first output connected to the antenna port.
20. The remote compensator of claim 5 further comprising a combiner including a first input connected to an output of the phase shifter, a second input connected to a second output of the first antenna-side circulator, and an output connected to an input of the receive amplifier circuitry.