A Novel Way to Increase the Accuracy of Current-Calculating on Metal Surface Using FDTD Method

In calculating the surface current of metal block using FDTD method, the tangential components of magnetic field on metal block surface cannot be obtained directly, most common way is to use the tangential components of adjacent grid to replace the real tangential magnetic field of metal block to calculate surface current. But when the test points are close to geometry edge, the magnetic field changes acutely, there will be a certain error using this method. The simulation results in this paper proved this phenomenon. In view of this issue, this paper proposes a surface current calculation method based on the Ampere circulation integral algorithm. The simulation results show out that this new method is a very efficient way to improve the calculation precision of surface current at the price of little increasing of computational complexity, and the accuracy of RCS result is increasing in some special angle.