Calculations on input impedance of a transmission lines?

Answer:
I assume you are wanting to know about balancing networks to a transmission line? If this is the case, you really need to get a book on networks and filters. The physical makup of the transmission line will impact this calculation. The basic idea is you want to match the impedance at the input (looking out of the transmission line) to the same impedance as the transmission line (say 50 or 75 ohms for typical coax), and the output impedance (looking out of the transmission line) to the same as well. This will result in maximum power transfer, minimum power reflection.

If you want to know how to make a balancing filter to a transmission line, then you need to design the filter according to your requirements - chebyshev, minimum ripple, wide band, narrow band, etc; You may need to use transformers to isolate the transmission line from your power circuitry, and use this as a matching network. You could also use transistors to accomplish similar things (less isolation, though), depending on what you're trying to do.
First answer by Littlewats. Last edit by Littlewats. Contributor trust: 63 [recommend contributor recommended]. Question popularity: 2 [recommend question].