Leakage at the end of scattered field in total field-scattered field of FDTD

hi all,

I have simulate 2d fdtd with total field scattered field + PML, but I have detected some serious leakage at the end of scattered field where i=ilast, j=jlast. Can anyone explain to me why is this happened?

The way you describe your problem is very vague, what do you mean "leakage" and "at the end of scattered field"?
Is your scatterer a PEC or dielectric square? What is the size of scatterrer compared with wavelength? What is the incident angle of your planewave? This is something we talk about scattering.