A modified INBC in the FDTD method based on the network cascade

A new modified impedance boundary network conditions (INBC's) is proposed in the finite-difference time domain (FDTD) method, aiming at the problem of poor stability and low precision of traditional FDTD-INBC algorithm. The algorithm regards the air layer between the dielectric surface and the half-grid as a two-port network, and cascades with the dielectric layer to form a cascade network, and then derives the INBC formula and its FDTD time-domain iteration calculation equation under the cascade network.