High-Resolution 160-GHz Imaging MIMO Radar Using MMICs With On-Chip Frequency Synthesizers

A high-resolution frequency-modulated continuous wave imaging radar for short-range applications is presented. A range resolution of about 1 cm is achieved with a bandwidth of up to 16 GHz around 160 GHz. In order to overcome losses and large tolerances on a printed circuit board (PCB), eight coherently coupled monolithic microwave integrated circuits (MMICs) are used, each with one transmit and receive antenna on-chip and each representing a single-channel radar system. The signals on the PCB are below 12 GHz, which facilitates fabrication and enables a design with low-cost substrates. The MMIC comprises a phase noise (PN)-optimized architecture with a fully integrated on-chip frequency synthesizer. Due to partly uncorrelated PN between the frequency synthesizer components, the noise level is increased in bistatic radar measurements between two different MMICs, which is explained by a thorough PN analysis. Time-division multiplexing is used to realize a multiple-input multiple-output system with a virtual array of 64 elements and an angular resolution better than 1.5° for the designed array. The positioning tolerances of the MMICs are included into the design resulting in a robust array design. The high-resolution radar performance is proven by imaging radar measurements of two exemplary scenarios.