SUMMARYThe feasibility of numerical calculations of a through-hole via using the Matrix-Penciled Moment Method (MP-MM) proposed by Show-Gwo Hsu and Ruey-Beei Wu is investigated. It shows that the MP-MM cannot be used to the via that is near the source port, and there is a lower bounded operating wavelength beyond which MP-MM is not applicable. The conclusions in this paper are proven by both theory and the simulation results obtained by Ansoft's HFSS.