The input impedance of a λ/8 section of a lossless transmission line of characteristic impedance 50 Ω is found to be real when the other end is terminated by a load ZL = R + jX. If X is 30 Ω, the value of R is ......
zin = z0((zL + jz0tanβl)/(zL + jzLtanβl))
l = λ/8
βl = 2π/λ x λ/8
= π/4
tan(βl) = tan(π/4) = 1
