To satisfy the demand for the miniaturization and universality of wideband-frequency synthesizers inradio-frequency and microwave circuits, SiP technology based on high-temperature co-fired ceramics (HTCC) is utilizedto miniaturize wideband-frequency synthesizers in this study, and multifunctional circuits are utilized for signalamplification, 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 engineeringapplications. This design can promote the engineering application of wideband-frequency synthesizers.