Progress in Multifunctional Microwave-Thermal Ceramic Materials for 6G RF Front-Ends

Release time：

2025-09-05

As 5G/6G communications evolve toward integrated space-air-ground-sea networks, conventional functional ceramics face growing limitations in simultaneously achieving stable microwave signal transmission and precise temperature sensing across broad temperature ranges.Especially with the expansion into Ku/Ka-band millimeter-wave communications, microwave dielectric ceramics require three key properties: tunable permittivity (εr) for device miniaturization, high Q·f value for enhanced frequency selectivity, and near-zero temperature coefficient of resonant frequency (τf) to ensure thermal stability.Simultaneously, negative temperature coefficient (NTC) thermosensitive ceramics, as thermal managers, require high linearity and high B-value over broad temperature ranges to real-time calibrate thermal drift.Spinel ceramics excel in single functions: MgAl₂O₄ offers superior microwave performance while MnFe₂O₄ exhibits NTC properties. However, intrinsic limitations exist—the former's ultra-high resistivity prevents thermosensitive functionality, and the latter's Fe³⁺/Fe²⁺ valence changes cause high-temperature electrical instability.

Previously, researchers at the Xinjiang Technical Institute of Physics and Chemistry, CAS, developed Mg₀.₈Mn₀.₂Al₁.₆Fe₀.₄O₄ ceramics via solid solution design, achieving a B-value of 8056 K. However, limitations such as oxygen vacancy-induced charge imbalance and non-Arrhenius behavior hindered compatibility between microwave performance and thermal linearity.

Recently, researchers addressed issues of nonlinear electrical properties and microwave loss in Mg-Al-Mn-Fe-O spinel ceramics at high temperatures by proposing a Sc³⁺ lattice anchoring strategy to regulate valence balance, simultaneously suppressing oxygen vacancy diffusion and strengthening octahedral bond valence.Experimental results demonstrate highly linear thermosensitive characteristics across an ultra-broad temperature range (200°C to 1000°C), meeting the linearity requirements for wide-temperature sensing applications.Simultaneously, the study achieved a balance of low εr, ultra-high Q·f, and near-zero τf in spinel ceramics.The cylindrical dielectric resonator antenna fabricated from this material achieved 92% radiation efficiency and 6.28 dBi gain at 12 GHz satellite communication frequency, demonstrating its potential for satellite communication front-end modules.

Related findings were published in Journal of Advanced Ceramics. The study was supported by the National Natural Science Foundation of China and Chinese Academy of Sciences projects.