Semi-analytical method for the determination of extrinsic and intrinsic model parameters for GaAs-based p-i-n diode is presented in this article. The main advantage is that the air-bridge interconnect inductance is regarded as an independent element and can be distinguished from the feedline effect. The detail model parameters extraction procedure is proposed, and the corresponding closed-form expressions are derived. Good agreement is obtained between the simulated and measured S-parameters up to 110 GHz to verify the validity of the approach.