SWRU639 February 2025
A normal FR4 board material results in unacceptable losses for the 77GHz antenna included in the top two layers of this design. This design uses ceramic material from Rogers Corporation to meet the dielectric requirements. This selection of material results in a lower variation in etched-feature dimensions. With wavelengths of less than 4mm, these tolerances are very important. By routing the 20GHz LO clock (FM_CW) on the same layer as the antennas, only one RO3003 core is required.
Figure 4-3 PCB Layer Stackup