In this paper, an L-band miniaturized frequency source which is designed and fabricated with three-dimensional packaging technology- LTCC (Low Temperature ceramic co-fired) is described. The structure of DDS+PLL is selected to increase frequency switching rate. The phase-locked loop, DDS, and low pass filter are reasonable designed to decrease phase noise. The testing results shows: frequency-hopping time is <20us, minimum resolution ratio is 10 kHz, and the size of the module is only 20mm×20mm×4.5mm,which meet the original goals.