A review of microwave dielectric ceramics: From fundamental mechanisms and property regulation to advanced preparation, applications, and data-driven discovery

Abstract Microwave dielectric ceramics (MWDCs) are pivotal to modern wireless communication systems, with their performance governed by three key parameters: relative dielectric constant (εr), Q×f value (product of quality factor Q (reciprocal dielectric loss) and frequency f), and temperature coefficient of resonant frequency (τf). This review systematically summarizes the recent research progress on MWDCs from five interrelated aspects. In terms of performance characterization, standardized resonant methods achieve εr measurement errors below 1% and a dielectric loss (tanδ) detection limit as low as 10−5. Theoretically, frameworks from complex crystal chemistry to the recently elucidated cation rattling effect enable quantitative interpretation of dielectric behavior. In processing, the cold sintering process achieves ceramic densification below 300 °C, reducing energy consumption by over 97% in comparison with conventional sintering. For applications, these materials have been widely deployed in high-performance substrates, resonators, and filters for 5G/6G communications, with device insertion loss maintained below 1 dB. Additionally, data-driven approaches, particularly machine learning, can accurately predict key dielectric properties with a coefficient of determination (R2) higher than 0.9, accelerating the exploration and development of novel MWDCs. By integrating these perspectives, this review offers systematic insight into the state-of-the-art progress and future development directions of MWDC research.