Utilizing RF-Chiplets For A Reconfigurable Automotive Radar System-In-Package

Inhalt:
Development of packaging and therein heterointegration of chiplets from different process nodes and technologies has gained widespread acceptance in digital systems. In contrast, analog circuits continue to rely on single chips with fragile bondwire interconnects, which are susceptible to environmental damage, offer limited predictability and require a more elaborate assembly. To address these limitations, we propose a concept that exploits the modular integrations’ cost, flexibility and scalability benefits by including multiple SiGe 130 nm B11HFC chiplets into an Infineon’s embedded Wafer Level Ball grid array (eWLB), as well as a Fraunhofer IZM’s Redistribution Line (RDL)-first package. Using only two chip designs, the proposed solution supports low-power or high-performance configurations by scaling the number of chiplets inside the package. Exemplarily, 4x4 short-range radar System in Package modules are presented that operate between 76-77 GHz. With a largely identical design, both package technologies are compared and the effects of their differences analyzed. Different 50 Ω transitions concepts are further evaluated to assess a potential standardized package interface. Each package is mounted onto a dedicated Printed Circuit Board (PCB) using standard C4 solderballs at highlighted, thermomechanically relevant positions. The PCBs also integrate frequency synthesizers, synchronization capabilities and a sparse 15.6 dBi comb-line antennas array. The entire modules unambiguously detected a 134.2 mm² radar cross-section corner reflector at a distance of 36m with ±30 deg angular resolution inside an enclosed test perimeter.