I. INTRODUCTION
A high-level of integration is essential to assemble Monolithic Microwave Integrated Circuits (MMIC) and radio frequency integrated circuits (RFIC) for 5G mm-wave communication systems in a single package. The MMICs and RFIC in turn, require low insertion losses, reflections, and cost to be realized for mm-wave frequencies. Therefore, the constraints for a representative 5G mm-wave 27.5GHz-28.35GHz handset design are many and in different fields, namely, electrical, physical area, thermal, and power. A popular and effective solution to overcome the constraints is using flip-chip bonding die in the multi-layer System-in-Package (SiP) approach because it provides compactness and cost savings by vertically integrating embedded components for additional functionality [1]. Multi-chip RF packages are forcing package design to become more challenging like chip design.