1. The problem statement, all variables and given/known data (a) A transmission line has a length, ℓ, of 0.4λ. Determine the phase change, βℓ, that occurs down the line. (b) A 50Ω lossless transmission line of length 0.4λ is terminated in a load of (40 + j30) Ω. Determine, using the equation given below, the input impedance to the line. [see attachment for equation] 2. Relevant equations As above. 3. The attempt at a solution (a) β = ω / fλ ∴ βℓ = ω 0.4λ / fλ = ω 0.4 / f = 0.4x2π f / f = 0.8π (=2.513 to 3d.p.) (b) Zin = 50 x [ (40cos0.8π) / ( 50cos0.8π + 30sin0.8π) ] = 70.91 ohms Do these answers look correct? Seems worryingly straightforward.