Dual-input, high power handling, power combining LNA for full duplex communications systems

1. An apparatus comprising:

a first input node that acquires a receive signal;

a second input node that acquires a cancellation signal and is separate from said first input node;

a first gain circuit configured to amplify said receive signal acquired through said first input node to generate an intermediate signal;

a combiner circuit configured to combine said intermediate signal with said cancellation signal acquired through said second input node to generate a combined signal, wherein (i) said cancellation signal is an attenuated version of a transmit signal and (ii) a portion of said transmit signal appears in said receive signal acquired through said first input node; and

a second gain circuit configured to amplify said combined signal to generate an output signal, wherein said first input node, said second input node, said first gain circuit, said combiner circuit and said second gain circuit form a low-noise amplifier.

2. The apparatus according to claim 1 , wherein said receive signal comprises one of a radio frequency signal, a microwave signal and a millimeter wave signal.

3. The apparatus according to claim 1 , wherein said first gain circuit comprises a field effect transistor having a drain node biased by said combiner circuit.

4. The apparatus according to claim 3 , wherein said second gain circuit comprises another field effect transistor having a gate node configured to acquire said combined signal from said combiner circuit.

5. The apparatus according to claim 1 , further comprising an amplifier (i) connected between said second input node and said combiner circuit and (ii) configured to amplify said cancellation signal.

6. The apparatus according to claim 5 , wherein (i) said first gain circuit comprises a field effect transistor having a drain node biased by said combiner circuit and (ii) said amplifier comprises another field effect transistor having a drain node biased by said combiner circuit and wired in parallel to said field effect transistor in said first gain circuit.

7. The apparatus according to claim 1 , wherein said combiner circuit comprises a wired-OR connection configured to receive both said intermediate signal and said cancellation signal.

8. The apparatus according to claim 1 , wherein said receive signal is acquired from one of a circulator circuit and a receive antenna.

9. The apparatus according to claim 1 , further comprising a mixer circuit (i) located between said combiner circuit and said second gain circuit and (ii) configured to change a frequency of said combined signal using a local oscillator signal.

10. The apparatus according to claim 1 , wherein said cancellation signal conveys greater than zero decibel-milliwatts of peak power.

11. The apparatus according to claim 1 , wherein said first gain circuit has an input 1 dB compression point of at least 4 decibel-milliwatts.

12. The apparatus according to claim 1 , wherein said first gain circuit, said combiner circuit and said second gain circuit are part of a full duplex wireless transceiver.

13. A method for dual-input low noise amplification, comprising the steps of:

amplifying a receive signal in a first gain circuit to generate an intermediate signal, wherein said receive signal is acquired through a first input node;

combining said intermediate signal with a cancellation signal in a combiner circuit to generate a combined signal, wherein (i) said cancellation signal is acquired through a second input node that is separate from said first input node, (ii) said cancellation signal is an attenuated version of a transmit signal, and (iii) a portion of said transmit signal appears in said receive signal acquired through said first input node; and

amplifying said combined signal in a second gain circuit to generate an output signal, wherein said first input node, said second input node, said first gain circuit, said combiner circuit and said second gain circuit form a low-noise amplifier.

14. The method according to claim 13 , wherein said receive signal comprises one of a radio frequency signal, a microwave signal or a millimeter wave signal.

15. The method according to claim 13 , further comprising the step of:

amplifying said cancellation signal between said second input node and said combiner circuit.

16. The method according to claim 13 , further comprising the step of:

heterodyning said combined signal between said combiner circuit and said second gain circuit using a local oscillator signal.

17. The method according to claim 13 , wherein said cancellation signal conveys between 10 decibel-milliwatts and 30 decibel-milliwatts of power.

18. The method according to claim 13 , wherein said first gain circuit has an input 1 dB compression point of at least 4 decibel-milliwatts.

19. The method according to claim 13 , wherein the steps are performed in a full duplex wireless transceiver.

20. An apparatus comprising:

a circulator circuit configured to (i) transfer an antenna signal to a receive signal and (ii) transfer a transmit signal to said antenna signal, wherein a portion of said transmit signal appears in said receive signal;

an attenuator circuit configured to attenuate and phase shift a cancellation signal derived from said transmit signal; and

a low-noise amplifier (i) comprising a plurality of gain circuits, a first input node that acquires said receive signal and a second input node that acquires said cancellation signal and is separate from said first input node and (ii) configured to (a) combine said receive signal with said cancellation signal after a first gain circuit of said plurality of gain circuits to generate a combined signal and (b) amplify said combined signal in a second gain circuit of the plurality of gain circuits to generate an output signal.