To satisfy the demand for the miniaturization and universality of wideband-frequency synthesizers in radio-frequency and microwave circuits, SiP technology based on high-temperature co-fired ceramics (HTCC) is utilized to miniaturize wideband-frequency synthesizers in this study, and multifunctional circuits are utilized for signal amplification, frequency division, and frequency doubling. This design affords a miniature wideband-frequency synthesizer(0.1-40 GHz) measuring 15 mm×12 mm×3 mm, and its performance satisfies the demand of engineering applications. This design can promote the engineering application of wideband-frequency synthesizers.