The following parameters are given:

500m homogeneous transmission line.

R' = 4.6 Ohm/km
G' = 0.5 uS/km
L' = 2 mH/km
C' = 800nF/km
r2 = 0.6 (sendondary side refl. coeff.)
ω = 200k
Uin = U1 = 60V + 0j

Question: What is the voltage U2 across the Load impedance ZL? For ω= 200k and Uin = 60V

My Idea:

Calculating ZW first (Wire Impedance) enter image description here

Then calculating the Load Impedance: enter image description here

Now i think about this circuit like two series impedances and i think i could use the resistor dividor approach to get the voltage u2 across the Load impedance:

enter image description here

Calculating: enter image description here

Unfortunately this result isnt correct. I am not be able to figure out where i did a mistake.

Do i have to take the refl. coeff into account again?

Would be happy about anything helpful. Thanks.

  • \$\begingroup\$ ω=0 ? at Uin .. \$\endgroup\$ Jun 3, 2019 at 14:18
  • \$\begingroup\$ ω is 200k at Uin = 60V \$\endgroup\$
    – C. Hediger
    Jun 3, 2019 at 14:24
  • \$\begingroup\$ What is the supposed correct result? \$\endgroup\$
    – Andy aka
    Jun 3, 2019 at 14:43
  • \$\begingroup\$ The correct result is probably: 88.174V * e^(j163 Deg) \$\endgroup\$
    – C. Hediger
    Jun 3, 2019 at 14:46
  • \$\begingroup\$ Why do you call r2 the "secondary side" reflection coefficient? Is there a transformer in your system? Is your transmission line connected to the secondary side or the primary side of the transformer? \$\endgroup\$
    – The Photon
    Jun 3, 2019 at 14:55

1 Answer 1


you calculated the impedance of the transmission line, but you failed to take into account that is per unit of distance, km in this case you just need to divide each parameter you got by half(500m is 0.5km) and it should be fine.

I see no other errors in your calculation.


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