This paper presented a 76–81 GHz FMCW MIMO Radar transceiver with mixed-mode PLL. Utilizing series-fed patch antenna array, a prototype system is developed based on the proposed transceiver. On-chip Measurements show that reconfigurable sawtooth chirps could be generated with a bandwidth up to 4 GHz and a period as short as 30 μs . Real-time experiments demonstrate that the prototype MIMO radar has the ability of target detection and achieves an angular resolution of 9°