Breaking the densification temperature bottleneck of CaZrO₃-based ceramics: Toward high-performance applications in C-band antenna and C0G-type MLCCs

Radio-frequency (RF) and microwave dielectric ceramics are key materials for high-frequency electronic devices. Among them, perovskites outperform conventional dielectrics due to their high quality factor (Q = 1/dielectric loss) and exceptional reliability. However, their practical application is limited by the trade-off between Q × f and the temperature coefficient of resonant frequency (τ_f), as well as by their high densification temperature (≥ 1500 °C). Here, a synergistic strategy combining B-site complex-ion modification with composite sintering-aid engineering is proposed. The optimized 95CZT05CMN composition exhibits excellent microwave dielectric properties of dielectric constant ε_r = 32.4, Q × f = 34,240 GHz, and τ_f = +16.8 ppm/°C at 1540 °C. More importantly, the 5G1L0.5C-modified ceramics can be densified at 950–1050 °C while retaining favorable dielectric properties (ε_r = 27.3–31.9, Q × f = 12,920–13,400 GHz, τ_f = −6.1 to −11.6 ppm/°C), together with a high flexural strength of 212 MPa. Furthermore, a C-band dielectric resonator antenna delivers radiation efficiency above 85%, while multilayer ceramic capacitors (MLCCs) fabricated show excellent C0G-type stability (ΔC/C_{25 °C} within ± 0.3%) and a dielectric loss of ∼0.06% at 1 MHz. These results establish a viable route toward low sintering temperature, low-loss and thermally stable CaZrO₃-based perovskites for advanced RF and integrated electronic applications.