Flip-Chip-Based Multichip Module for Low Phase-Noise $V$ -Band Frequency Generation

This paper reports on a flip-chip (FC)-based multichip module (MCM) for low phase-noise (PN) V-band frequency generation. A high-performance ×8 GaAs metamorphic high-electron mobility transistor monolithic microwave integrated circuit (MMIC) multiplier and a low PN 7-GHz GaAs InGaP heterojunction bipolar transistor (HBT) MMIC oscillator were used in the module. The microstrip MMICs were FC bonded to an Al₂O₃ carrier with patterns optimized for low-loss transitions. The FC-based module was experimentally characterized to have a PN of -88 dBc/Hz @ 100-kHz offset and -112 dBc/Hz @ 1-MHz offset with an output power of 11 dBm. For comparison, the MMICs were also FC bonded as individual chips and the performance was compared with the bare dies without FC bonding. It was verified that the FC bonding has no detrimental effect on the MMIC performance. The tests revealed that the FC module provided improved performance. To our best knowledge, this is the first FC-based module for millimeter-wave frequency generation. The module also presents one of the best PN reported for millimeter-wave frequency sources.