Experimental characterization of channel crosstalk in interleaved array antennas for FMCW radar

The inter-channel isolation of an FMCW radar with interleaved transmit-receive array antennas is, for the first time, characterized by measurements on an operative system. Theoretical predictions, based on full-wave simulations, are compared to computations from the measured antenna scattering parameters. In both cases, the received signals are re-combined by using ideal equi-phase and equi-amplitude power distribution networks. Two 1 to 32 Wilkinson power dividers are then fabricated and the radar inter-channel isolation is measured directly between the input (transmit) port and the output (receive) port of the system, recording a crosstalk of -34 dB. The effects of the system non-idealities on the antenna isolation are discussed.