Interferometric quadrature down-converter for 77 GHz automotive radar: Modeling and analysis

This paper describes a millimeter wave quadrature down-converter module based on the interferometric principle. The computer model of the six-port interferometer is implemented using S-parameter measurements of a 90° hybrid coupler fabricated on thin alumina substrate. This model is validated by full two-port measurements of the six-port. Down-converter error vector modulation results are analyzed using an envelope simulation. The proposed architecture is suitable for low-cost, high-performance, reconfigurable millimeter wave automotive radar and communication front-ends.