Comment on “A Dual-Frequency Transformer for Complex Impedances With Two Unequal Sections”

The analysis presented in the above titled paper is defective because equations (7a)-(7d) are based on the assumption that the complex impedances Z
₀
and Z
_L
do not change when the frequency changes from
f

₁
to f
₂
= m
f

₁
. As a result, the numerical solutions based on these equations are not valid either.