10 GHz GaInP/GaAs HBT injection-locked frequency divider

The first integrated GalnP/GaAs heterojunction bipolar transistor (HBT) injection-locked frequency divider (ILFD) with the stacked transformers is demonstrated at 9.60-10.38 GHz. The stacked trans formers formed by only two metal layers provide the inductive coupling in the cross feedback and separate biasing for base and collector to allow for the larger voltage swing in the LC tank and increasing locking range. Under the supply voltage of 5 V and core power consumption of 20.5 mW, the locking range is up to 7.8% of the center operating frequency. Compared to other high frequency ILFDs employing a current source as signal injector, the design has a good performance in locking range. The chip size is 1.0 mm x 1.0 mm.