Flip-Chip Assembled 7 GHz Ultra-Low Phase-Noise InGaP HBT Oscillator
Keywords: Flip-chip, Interconnection, MMIC, Oscillator, Phase noise, Microwave.
This paper reports on a flip-chip assembled 7 GHz ultra-low phase-noise GaAs InGaP heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) oscillator. The cross-coupled oscillator was flip-chip bonded to an in-house fabricated Al2O3 carrier with patterns optimized for low-loss transitions. After flip-chip, the phase noise of the crosscoupled InGaP HBT oscillator was improved due to an increased Q-factor of the resonant tank. An ultra-low phase-noise of -112 dBc/Hz @ 100 kHz offset and -128 dBc/Hz @ 1 MHz offset with a high output power of 7 dBm at 7 GHz was achieved. To our best knowledge, this is the lowest phase noise reported for a flip-chip assembled oscillator.