This paper presents a multibias optimizing parameter extraction technique for Heterojunction Bipolar Transistor (HBT) small-signal model. The corresponding equations for intrinsic and extrinsic elements have been established in according with small-signal HBT model through formula derivation. A multibias decomposition-based optimization method is discussed. Robustness and accuracy of optimization method are tested on measured S-parameters of GaInP/ GaAs HBT device. Results show that the extracted parameters have the characteristics of exclusive astringency and accuracy with a different set of random starting values

and the relative error between the simulated results and the values measured is less than 1%.