Hybrid radio frequency combining system with signal cancellation

Abstract

A system and method for reducing intermodulation interference between a transmitter circuit and a receiver circuit includes a first hybrid combiner coupled to a transmit port, a second hybrid combiner coupled to an antenna port, a third hybrid combiner coupled to a receive port, a first three port network coupled to the first hybrid combiner, the second hybrid combiner, and the third hybrid combiner, and a second three port network coupled to the first hybrid combiner, the second hybrid combiner, and the third hybrid combiner. Related apparatus, systems, techniques and articles are also described.

What is claimed is: 
     
         1 . A system for reducing intermodulation interference between a transmitter circuit and a receiver circuit, the system comprising:
 a first hybrid combiner coupled to a transmit port;   a second hybrid combiner coupled to an antenna port;   a third hybrid combiner coupled to a receive port;   a first three port network coupled to the first hybrid combiner, the second hybrid combiner, and the third hybrid combiner; and   a second three port network coupled to the first hybrid combiner, the second hybrid combiner, and the third hybrid combiner.   
     
     
         2 . The system of  claim 1 , wherein the first hybrid combiner is configured to split an input transmit signal to a first transmit output and a second transmit output, wherein the first transmit output is phase shifted;
 wherein the first three port network is configured to receive the second transmit output signal;   wherein the second three port network is configured to receive the second transmit output signal;   wherein the second hybrid combiner is configured to receive the first transmit output signal and the second transmit output signal, phase shift the first signal to form a phase-shifted signal, combine the phase-shifted signal with the second transmit output signal to form a combined signal, and provide the combined signal to the antenna port.   
     
     
         3 . The system of  claim 2 , wherein the second hybrid combiner is configured to receive a receive signal from the antenna port, split the receive signal into a first receive output and a second receive output, the first receive output phase shifted, provide the first receive output to the first three port network, and provide the second receive output to the second combiner;
 wherein the third hybrid combiner is configured to receive the first receive output, phase shift the first receive output, receive the second receive output, combine the first receive output and the second receive output to form a combined receive output, and provide the combined receive output signal to the receive port.   
     
     
         4 . The system of  claim 1 , further comprising:
 a first gain block including circuitry, the first gain block coupled to the first hybrid combiner, the first three port network, and the second three port network.   
     
     
         5 . The system of  claim 1 , further comprising:
 a second gain block including circuitry, the second gain block coupled to the third hybrid combiner, the first hybrid combiner, and the second hybrid combiner.   
     
     
         6 . The system of  claim 1 , further comprising:
 control circuitry configured to receive the first receive output signal and the second receive output signal, the control circuitry configured to phase shift and/or attenuate at least one of the first receive output signal and/or the second receive output signal.   
     
     
         7 . The system of  claim 6 , wherein the control circuitry includes at least one phase shifter and at least one attenuator. 
     
     
         8 . The system of  claim 6 , further comprising control logic configured to:
 receive a first signal characterizing a transmit signal level at the transmit port;   receive a second signal characterizing a receive signal level at the receive port; and   control the control circuitry to reduce a level of transmit signal at the receive port.   
     
     
         9 . The system of  claim 6 , further comprising control logic configured to:
 receive a first signal characterizing a receive signal level at the receive port;   determine intermodulation signal components of the first signal; and   control the control circuitry to reduce a level of intermodulation signal component at the receive port.   
     
     
         10 . The system of  claim 6 , further comprising control logic configured to:
 receive a first signal characterizing a transmit signal level at the transmit port;   receive a second signal characterizing a receive signal level at the receive port;   determine intermodulation signal components of the second signal; and   control the control circuitry to reduce a level of transmit signal at the receive port and to reduce a level of intermodulation signal component at the receive port.   
     
     
         11 . A method of reducing intermodulation interference between a transmitter circuit and a receiver circuit, the method comprising:
 receiving a first signal characterizing a transmit signal level at a transmit port;   receiving a second signal characterizing a receive signal level at a receive port; and   controlling control circuitry to reduce a level of transmit signal at the receive port.   
     
     
         12 . The method of  claim 11 , wherein the receiving, and the controlling is performed by control logic forming part of circuitry comprising:
 a first hybrid combiner coupled to the transmit port;   a second hybrid combiner coupled to an antenna port;   a third hybrid combiner coupled to the receive port;   a first three port network coupled to the first hybrid combiner, the second hybrid combiner, and the third hybrid combiner; and   a second three port network coupled to the first hybrid combiner, the second hybrid combiner, and the third hybrid combiner.   
     
     
         13 . The method of  claim 12 , wherein the first hybrid combiner is configured to split an input transmit signal to a first transmit output and a second transmit output, wherein the first transmit output is phase shifted;
 wherein the first three port network is configured to receive the second transmit output signal;   wherein the second three port network is configured to receive the second transmit output signal;   wherein the second hybrid combiner is configured to receive the first transmit output signal and the second transmit output signal, phase shift the first signal to form a phase-shifted signal, combine the phase-shifted signal with the second transmit output signal to form a combined signal, and provide the combined signal to the antenna port;   wherein the second hybrid combiner is configured to receive a receive signal from the antenna port, split the receive signal into a first receive output and a second receive output, the first receive output phase shifted, provide the first receive output to the first three port network, and provide the second receive output to the second combiner;   wherein the third hybrid combiner is configured to receive the first receive output, phase shift the first receive output, receive the second receive output, combine the first receive output and the second receive output to form a combined receive output, and provide the combined receive output signal to the receive port.   
     
     
         14 . The method of  claim 11 , the system further comprising a first gain block including circuitry, the first gain block coupled to the first hybrid combiner, the first three port network, and the second three port network; and a second gain block including circuitry, the second gain block coupled to the third hybrid combiner, the first hybrid combiner, and the second hybrid combiner. 
     
     
         15 . The method of  claim 11 , wherein the control circuitry is configured to receive the first receive output signal and the second receive output signal, the control circuitry configured to phase shift and/or attenuate at least one of the first receive output signal and/or the second receive output signal; wherein the control circuitry includes at least one phase shifter and at least one attenuator. 
     
     
         16 . A method comprising:
 receiving a first signal characterizing a receive signal level at the receive port;   determining intermodulation signal components of the first signal; and   controlling control circuitry to reduce a level of the intermodulation signal components at the receive port.   
     
     
         17 . The method of  claim 13  wherein the receiving, the determining, and the controlling is performed by control logic forming part of circuitry comprising:
 a first hybrid combiner coupled to a transmit port; 
 a second hybrid combiner coupled to an antenna port; 
 a third hybrid combiner coupled to the receive port; 
 a first three port network coupled to the first hybrid combiner, the second hybrid combiner, and the third hybrid combiner; and 
 a second three port network coupled to the first hybrid combiner, the second hybrid combiner, and the third hybrid combiner. 
 
     
     
         18 . The method of  claim 17 , wherein the first hybrid combiner is configured to split an input transmit signal to a first transmit output and a second transmit output, wherein the first transmit output is phase shifted;
 wherein the first three port network is configured to receive the second transmit output signal;   wherein the second three port network is configured to receive the second transmit output signal;   wherein the second hybrid combiner is configured to receive the first transmit output signal and the second transmit output signal, phase shift the first signal to form a phase-shifted signal, combine the phase-shifted signal with the second transmit output signal to form a combined signal, and provide the combined signal to the antenna port;   wherein the second hybrid combiner is configured to receive a receive signal from the antenna port, split the receive signal into a first receive output and a second receive output, the first receive output phase shifted, provide the first receive output to the first three port network, and provide the second receive output to the second combiner;   wherein the third hybrid combiner is configured to receive the first receive output, phase shift the first receive output, receive the second receive output, combine the first receive output and the second receive output to form a combined receive output, and provide the combined receive output signal to the receive port.   
     
     
         19 . The method of  claim 16 , the system further comprising a first gain block including circuitry, the first gain block coupled to the first hybrid combiner, the first three port network, and the second three port network; and a second gain block including circuitry, the second gain block coupled to the third hybrid combiner, the first hybrid combiner, and the second hybrid combiner. 
     
     
         20 . The method of  claim 16 , wherein the control circuitry is configured to receive the first receive output signal and the second receive output signal, the control circuitry configured to phase shift and/or attenuate at least one of the first receive output signal and/or the second receive output signal; wherein the control circuitry includes at least one phase shifter and at least one attenuator.