As global telecommunications transition from 5G to 6G and sub-terahertz (THz) frequency bands, wireless communications are entering an era defined by ultra-high frequencies, immense bandwidths, and ultra-low latencies. However, in accordance with Maxwell's equations, higher electromagnetic frequencies suffer severe signal attenuation and propagation delays when traversing dielectric media. When high-frequency signals pass through antenna substrates, printed circuit boards (PCBs), or integrated circuit encapsulation materials, the intrinsic dielectric constant (relative permittivity, $k$ or $varepsilon_r$) and dielectric loss tangent ($tandelta$) of the substrate material constitute critical performance bottlenecks. Formulating electronic substrate materials possessing ultra-low dielectric constants and dielectric loss factors has become a priority in high-frequency radio frequency (RF) engineering.

Conventional high-frequency circuit substrates—such as polytetrafluoroethylene (PTFE) and polyimide (PI)—exhibit excellent electrical insulation, yet their dielectric constants typically range from 2.0 to 3.5. Under millimeter-wave (30 GHz – 300 GHz) and THz operational regimes, dielectric values in this range induce substantial parasitic capacitance, signal phase distortion, and thermal dissipation losses. Electromagnetic theory indicates that dry air possesses a dielectric constant approaching unity ($k=1.0$ in vacuum), making gaseous air the ideal low-dielectric medium. Introducing gas-filled porosity into solid materials is the most effective method for suppressing permittivity.

Aerogels, owing to their porosities ranging between 90% and 99%, mirror the dielectric response of air, positioning them as candidates for next-generation low-dielectric electronic substrates. Silica and polyimide aerogels exhibit dielectric constants as low as 1.05 to 1.25, alongside dielectric loss tangents controlled on the order of $10^{-3}$ to $10^{-4}$. These ultralow dielectric parameters diminish signal propagation delays within circuit architectures, while mitigating attenuation driven by conductor skin-effect losses at high-frequency conductor-dielectric interfaces. This enables improvements in signal integrity, transmission speeds, and power consumption metrics.

In microelectronic packaging and high-frequency antenna engineering, low-dielectric aerogel composites demonstrate significant utility. In 5G/6G millimeter-wave phased-array antenna modules, incorporating flexible polyimide aerogel films as antenna substrates or radomes yields improvements in antenna gain and radiation efficiency, while suppressing phase distortion across high-frequency bands. Within integrated circuit (IC) packaging architectures for mobile communication units, high-performance servers, and edge computing hardware, aerogel dielectric layers eliminate interlayer parasitic capacitance, preventing signal crosstalk between adjacent interconnect lines. As progress continues in ultra-thin aerogel film synthesis and surface planarization techniques, aerogels are transitioning from thermal insulation media to high-frequency dielectric materials, providing the electromagnetic infrastructure for future wireless networks.