The first Integrated GaInP/GaAs heterojunction bipolar transistor (HBT) Injection-locked frequency divider (ILFD) with the stacked transformers h demonstrated at 9.60-10.38 GHz. The stacked transformers formed by only two metal layers provide the Inductive coupling in the cran feedback and separate biasking 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 In 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 × 1.0 mm.