The talk will show how low-cost 2×2 and 4×4 MIMO 5G phased-arrays at 28GHz have the EIRP and NF required for UaV detection up to 300 meters with high SNR. All what is needed is that the waveform be changed to an FMCW waveform, and one phased-array be used solely in transmit-mode while the other phased-array be used solely in receive mode. It is shown that one can obtain >65dB isolation between the arrays, which is excellent for FMCW systems. A working system detecting a UaV with an RCS of 0.01m² (-20dBsm) up to 300 meters is shown.