High Performance Waveguide Launcher in Interposer Package Technology for 77/79 GHz Automotive 4D Imaging Radar

This paper presents a new low-loss and compact Launcher-in-Interposer Package (LiIP), designed for automotive radar applications in the 77 / 79 GHz frequency band, specifically targeting 4D imaging MIMO radar with waveguide-based antennas. The proposed LiIP utilizes a fully differential microstrip line to waveguide launcher to ensure robust signal integrity and effective impedance matching. The design is realized using embedded wafer-level ball grid array (eWLB) packaging technology integrated with High-Density Interconnect (HDI) interposer. A back-to-back implementation of the launcher was designed and fabricated, to extract the insertion loss of the launcher. Moreover, a 4Tx-4Rx MIMO radar package was implemented by exploiting the proposed LiIP. Based on the location of the waveguide ports in the package, the routings of the LiIPs in the interlayers of the interposer for different transmitters and receivers are designed and adjusted to provide an in-phase MIMO radar system with approximately 40 dB isolation between the waveguide ports. The new radar package demonstrates a conversion gain of approximately 41 dB, a noise figure of 11 dB, and an output power of about 15 dBm. These results underline the new LiIP's potential for enabling high-performance 4D imaging radar systems with 3D waveguide antennas.