A 94 GHz radar using a six-port reflectometer as a phase/frequency discriminator

A 94 GHz radar sensor is proposed. The receiver front-end module of this system is based on a six-port reflectometer used as a phase/frequency discriminator. This device determines Doppler frequency (and consequently, relative speed) by means of the phase difference between transmitted and received signals. For the first time at this frequency, measurements with a real moving target are performed. The six-port circuit equations, the radar operating principle and architecture and speed measurements are presented