Preparation and microwave dielectric properties of temperature-stable low-dielectric (1−x)Li₂MoO₄−xBi_0.4Ce_0.6VO₄ ceramics for satellite communication applications

In this study, a series of ([Formula: see text]x)Li 2 MoO 4 [Formula: see text]xBi 0.4 Ce 0.6 VO 4 [x = 0.25, 0.35, 0.45, 0.55, ([Formula: see text]x)LM–xBCV] microwave dielectric ceramics, capable of being sintered at low temperatures, were synthesized using the solid-phase method. The temperature coefficient of resonance frequency in LM microwave dielectric ceramics was effectively modulated through the incorporation of BCV with tetragonal zirconia phases, resulting in the formation of composite ceramics. This approach led to the development of a low-permittivity ([Formula: see text] r ∼ 12.6) microwave dielectric ceramic material exhibiting a near-zero temperature coefficient (TCF ∼ +0.5 ppm/ ∘ C). The composite, specifically 0.55LM–0.45BCV, achieved ultra-low temperature sintering below [Formula: see text]C and demonstrated excellent performance as low-temperature co-fired ceramic materials, with good co-firing compatibility with metallic silver. Furthermore, the volatilization of lithium and bismuth elements was effectively mitigated through the burying sintering process. Which resulted in a substantial enhancement of the [Formula: see text] (Q and f denote the quality factor and the resonant frequency, respectively) value for the 0.55LM–0.45BCV ceramics, achieving an increase of nearly threefold (Q × f [Formula: see text] [Formula: see text]GHz). To investigate the application potential of 0.55LM–0.45BCV ceramic, particularly in the context of low-orbit communication satellites, a circularly polarized patch antenna was designed utilizing 0.55LM–0.45BCV ceramic as the dielectric substrate material. The antenna demonstrated a high simulated radiation efficiency of 93.8% and a gain of 4.0[Formula: see text]dBi at a center frequency of 1.559[Formula: see text]GHz, indicating its promising applicability in the domain of orbital satellite communication.