A GaAs-HBT Distributed Amplifier with Near-fT Cut-off Frequency for High-Bitrate Transmissions
(2004)
A MMIC Colpitts oscillator in push-push configuration with integrated frequency divider using InGaP/GaAs HBTs is presented. The output is taken from the second harmonic port while the fundamental signal is fed to a frequency divider by two thus providing a reference signal at one quarter of the output frequency. The MMIC VCO reaches state-of-the-art phase-noise performance in X-band down to -120dBc/Hz at 1MHz offset frequency at high output power and a tuning range of 4%.
24 GHz VCOs and frequency dividers with very low power consumption are presented. The circuits are realized as GaAs HBT MMICs. They comprise a VCO with high efficiency >17% and 12% tuning range at only 18 mW DC consumption as well as several frequency dividers. In order to minimize power consumption, the latter use the injection-locked frequency-divider (ILFD) concept. Divider ratios of 2 and 4 are realized, power consumption as low as 25 mW for a divider-by-2 is achieved. This demonstrates the capabilities of the analog concept in realizing dividers for mm-wave frequencies at DC consumption levels far below their digital counterparts