  An adaptive interpolation scheme is proposed to accurately calculate the
wideband responses in electromagnetic simulations. In the proposed scheme, the
sampling points are first carefully divided into several groups based on their
responses to avoid the Runge phenomenon and the error fluctuations, and then
different interpolation strategies are used to calculate the responses in the
whole frequency band. If the relative error does not satisfy the predefined
threshold in a specific frequency band, it will be refined until the error
criteria is met. The detailed error analysis is also presented to verify the
accuracy of the interpolation scheme. At last, two numerical examples including
the antenna radiation and the filter simulation are carried out to validate its
accuracy and efficiency.
