Integrated Suspended Line: A New Heterogeneous Integration for 5G/6G RF Integrated Circuits

Kaixue Ma; Yongqiang Wang

doi:10.1016/j.eng.2026.10.002

Engineering ›› :202610002 DOI: 10.1016/j.eng.2026.10.002

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Integrated Suspended Line: A New Heterogeneous Integration for 5G/6G RF Integrated Circuits

Kaixue Ma ^*
, Yongqiang Wang ^*

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Abstract

With the evolution of ﬁfth-generation (5G)-advanced and sixth-generation (6G) mobile communication research, the demand for high-performance, miniaturized radio frequency (RF) integrated circuits (ICs) has become increasingly pressing, particularly in emerging 5G/6G air–space–ground–sea integrated com- munication scenarios that impose stringent requirements on RF front-end performance. As a heteroge- neous integration platform, integrated suspended line (ISL) technology alleviates the loss bottleneck of conventional transmission lines by suspending the signal line in an air cavity, thereby reducing both dielectric and radiation losses. Its self-packaging and multilayer integration reduce circuit volume and weight while remaining compatible with 5G/6G air–space–ground–sea integrated RF applications. This paper summarizes the four typical structures of ISL (i.e., substrate integrated suspended line (SISL), metal integrated suspended line (MISL), silicon-based integrated suspended line (Si-ISL), and hybrid integrated suspended line (HISL)), reviews its applications in microwave/millimeter-wave circuits, and discusses its potential in 5G/6G air–space–ground–sea integrated communication systems.

Keywords

Integrated suspended line / Air-cavity embedded multilayer structure / Low loss / Highintegration / Self-packaging / Heterogeneous integration circuits / 5G/6G

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Kaixue Ma, Yongqiang Wang. Integrated Suspended Line: A New Heterogeneous Integration for 5G/6G RF Integrated Circuits. Engineering 202610002 DOI:10.1016/j.eng.2026.10.002

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