Abstract: An efficient time domain hybrid method consisting of finite difference time domain (FDTD) method with subgridding technique, transmission line (TL) equations and state variable method is proposed to address the coupling problem of bent printed circuit board (PCB) trace with right-angled chamfer corners (RACCs). Firstly, the entire PCB trace is separated into multiple straight trace segments and RACC structures. And its equivalent circuit is further established using Norton’s theorem and Substitution theorem, with RACCs modeled as T-type circuits comprising inductance and capacitance elements. Then, the coupling models of these trace segments are constructed via the TL equations and solved by the FDTD to obtain the transient responses along these trace segments. Finally, the port voltages of RACC equivalent circuits are calculated using the state variable method, which are applied as boundary conditions and fed back to the trace segments, enabling bidirectional interference propagation along bent PCB trace. Numerous simulation cases are evaluated and compared with that of BLT equation and FDTD to verify the accuracy and efficiency of this method.