Analytical Modeling for the Radiation Characteristics of the GCPW to Quasi-Coaxial Structure in High-Speed Interconnection of SiP

High-speed signal interconnects in System-in-Package (SiP) components, especially the horizontal-to-vertical structure acting as a radiation source, cause electromagnetic radiation issues. These issues are the main contributors to Signal Integrity (SI), Power Integrity (PI), and Electromagnetic Interference (EMI) problems. Current research on the analytical modeling of radiation fields in SiP high-speed interconnect structures mainly focuses on simple and regular transmission structures, such as microstrip lines, while further research on the radiation characteristics of complex structures, such as horizontal-to-vertical transitions, is lacking. This paper primarily analyze the radiation issues of the key horizontal-to-vertical interconnect structure—the Grounded Coplanar Waveguide (GCPW) to quasi-coaxial transition—in high-speed interconnect links within SiP. An analytical model for the radiation characteristics is established based on an analytical approximation method. The finite element modeling and radiation characteristics analysis of the interconnect structure are carried out using the full-wave electromagnetic simulation software Ansys HFSS. The validity of the analytical model is verified through comparative analysis. The results showed that good agreement is achieved between the analytical model and the HFSS model. The radiation characteristics, radiation intensity, and transmission performance are influenced by the variations in the signal conductor length and dielectric thickness of GCPW. The proposed analytical model provides an efficient analytical tool for the design optimization and electromagnetic compatibility analysis of interconnect structures in SiP.