In simultaneous transmit and receive (STAR) systems, multi-tap RF self-interference cancellation (RF-SIC) filters are employed to prevent receiver saturation and achieve STAR communication. Specifically, RF-SIC filters aim to reproduce the frequency response of the interference channel between the transmit and receive antennas. In this paper, we apply ABCD-parameters, Y-parameters, and S-parameters to analyze the performance of a wideband RF-SIC filter design incorporating variable delays and coefficients. Numerical MATLAB calculations demonstrate strong agreement (< 2% error) with Advanced Design System (ADS) circuit simulations for a three-tap filter from 2 GHz–8 GHz.