Multipurpose 76,5 GHz Near Field Radar Sensor

The growing demand of automatic process supervision in various areas requires the development of new sensors. However, for most applications only single function sensors have been developed. For technical reasons (space, computation power) on the one hand and economical reasons (cost) on the other hand, a limit in the amount of parameters to be controlled will be reached soon and further improvement will be difficult. In this paper an innovative multifunctional radar sensor at millimetre wave frequency is presented. High precision distance measurements in the unambiguous range of half a wavelength is performed by analysing the received phase of a transmitted 76.5 GHz CW radar signal. The innovative improvement compared to pure Doppler measurement is to determine the distance to a fixed or moving object without contact by measuring the phase. An application would be the absolute position measurement of a car wheel for the GPS navigation system. Here, the eccentricity of the wheel is used as position indicator. In this paper for the first time a Low Temperature Cofired Ceramics (LTCC) substrate is presented for a millimetre wave application, saving space by integrating passive structures into the multi-layer LTCC substrate.