122 GHz FMCW Radar System-in-Package in LTCC Technology

This paper presents a low temperature cofired ceramic (LTCC) System-in-Package (SiP) at 122 GHz consisting of the following components: a radar monolithic microwave integrated circuit, Mushroom electromagnetic bandgap antennas and asymmetric stripline-to-grounded coplanar waveguide signal transitions designed on a high-frequency LTCC substrate, a package base for routing DC and baseband (BB) signals designed on a low-frequency LTCC substrate. The package base also acts as a heat sink and facilitates SiP encapsulation. The millimeter-wave interconnects are realized through self-matched, half-wavelength wirebonds and the BB interconnects are realized through conventional wirebonds. The SiP is partially encapsulated using a molding compound (Polytec TC 430-T). Measurement and simulation results of the SiP are presented from 110 to 150 GHz. The molded SiP is surface mounted on a BB printed circuit board, thus realizing a 122 GHz frequency modulated continuous wave radar, whose functionality is verified by measuring a target distance.