Circuit modeling of high-frequency devices described by tabulated multi-port parameters has generated immense interest during the recent years. In most cases, simple equivalent circuit models (S-ECM) are available to the designers, which correlate well with the measured parameters at lower frequencies, however, deviate at higher frequencies. Traditional efforts to improve equivalent circuit models are device-specific, laborious and ad-hoc in nature. In order to address these difficulties, this paper presents an efficient and automated algorithm to identify appropriate frequency-dependent elements for adding to the S-ECM at arbitrary locations, so as to correct for high frequency errors. The new method enables the designers to retain their existing physical models while providing a means to capture the high-frequency effects accurately.