We present an analytic method to extract Schottky diode parasitic model parameters. All the ten unknown model parameters are extracted via a straightforward step-by-step procedure. The challenges for a proper finger inductance and series resistance extraction are discussed and solutions are recommended. The proposed method is evaluated using three sets of S-parameter data for GaAs-based planar Schottky diodes, i.e., data from measurement up to 110 GHz and 3-D electromagnetic full-wave simulations up to 600 GHz. The extracted models agree well with the measured and simulated data.