  A new simulation technique to obtain the synchronized steady-state solutions
existing in coupled oscillator systems is presented. The technique departs from
a semi-analytical formulation presented in previous works. It extends the model
of the admittance function describing each individual oscillator to a piecewise
linear one. This provides a global formulation of the coupled system,
considering the whole characteristic of each voltage-controlled oscillator
(VCO) in the array. In comparison with the previous local formulation, the new
formulation significantly improves the accuracy in the prediction of the system
synchronization ranges. The technique has been tested by comparison with
computationally demanding circuit-level Harmonic Balance simulations in an
array of Van der Pol-type oscillators and then applied to a coupled system of
FET based oscillators at 5 GHz, with very good agreement with measurements.
