Forbidden regions of L‐section impedance matching networks on Meta‐Smith charts for conjugately characteristic‐impedance transmission lines

Abstract

ABSTRACTIn this article, the ZY Meta‐Smith chart (MSC) is applied to intuitively determine a forbidden region for all eight L‐section matching networks associated with conjugately characteristic‐impedance transmission lines (CCITLs) with nonnegative characteristic resistances (NNCRs), where a load impedance cannot be matched to a CCITL. Due to the fact that the ZY MSC for CCITLs with NNCRs depends on the argument ϕ of the characteristic impedances of CCITLs (which can be negative, zero, or positive), three cases for each L‐section matching network are considered to determine the effect of the argument ϕ on forbidden regions, resulting in a total of 24 cases for all L‐section matching networks. It is found that the ZY MSC for CCITLs with NNCRs is indeed a useful graphical tool for enabling intuition for radio‐frequency engineers with additional physical insight into impedance matching of L‐section matching networks. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:874–879, 2015