We report on fully integrated K-band synthesizer and signal converter modules. The designs are realized in low-temperature co-fired ceramics, making extensively use of the multilayer features and advanced capabilities of this substrate system. The interior packaging technology exclusively utilizes flip-chip mounting of bare semiconductors. As a key element a low phase noise synthesizer is integrated in a hermetic surface mount package of 8.7 mm × 15.8 mm, achieving an output power of more than 6 dBm in a range between 19.58-20.2 GHz. The stabilization is achieved by a fractional-N phase-locked loop, all required components being integrated inside and on top of the package. The synthesizer design is extended to dual-sideband and single-sideband converters by including mixers and couplers in the same package.