Question

All transmission line section in Figure, have a characteristic impedance R₀ + j₀. The input impedance Z_in equals

(a) 2/3 R₀ 

(b) R₀

(c) 3/2 R₀

(d) 2 R₀

Answer 1

(b) R₀

For \(\lambda\)/4 line, Z_in1 = \(\frac{Z_0^2}{Z_L}\) = \(\frac{R_0^2}{R_0/2}\) = 2R₀

For \(\lambda\)/2 line, Z_in2 = Z_L2 = 2R₀

For \(\lambda\)/8 line, Z_L = (2R₀) || 2R₀

= R₀

For transmission line of length l, Z_in