W-band Vivaldi antenna in LTCC for CW-radar nearfield distance measurements

A CW-radar sensor concept based on interferometric measurement is presented. The usage of LTCC as sensor substrate offers the possibility to create a highly integrated sensor module, including active and passive components. It is shown, that the antenna integration can be realized by using corrugations and special housing designs for shielding and isolating effects. The used tapered slot antenna with a planar phase front in a small distance related to the wavelength and the high directivity fulfills the requirements for achieving the aspired measurement accuracy of 1 μm or better. Without the usage of calibration algorithms, this accuracy would require a not achievable antenna matching. A calibration approach for eliminating the remaining error signal is shown in this paper.