Parasitic coupling to the ion Bernstein wave during fast wave heating is investigated using the WIGS computer code. The WIGS code models ion cyclotron range of frequencies (ICRF) antenna coupling to tokamak plasmas for phased coil antenna arrays in a recessed cavity. The antenna radiation resistance and the spectrum of the ICRF power coupled to the plasma are calculated. Parasitic coupling to the ion Bernstein wave is shown to be important for low parallel wavenumbers during minority ion heating with large gradients in the plasma density near the edge of the plasma. Results are presented for TFTR antenna and plasma parameters using experimental data