Intermodulation Interferences Immunity in Receiving Path of Active Antenna Array Based on NI USRP-2943 SDR Transceivers

Active antenna array is formed out of coherently and synchronously functioning software defined radio reconfigurable NI USRP-2943 transceivers. An analysis of nonlinear properties of NI USRP-2943 RF receiver channels with specified microelectronics devices for coherent and noncoherent composition of intermodulation interferences at output of each RF stage is performed. Spatial correlation matrixes of the sum of active and intermodulation interferences for active antenna array are evaluated. The angular power spectrum dependence on the nonlinear distortion in USRP RF receiving path and spatial configuration of active antenna array is analyzed. Power levels and angular positions of virtual spatial interferences corresponding products of nonlinear transformation in receiving path are calculated as well.