Page Started Nov 1, 2009
The Transmission Line
    Transmission lines!  Ah, so many books written, so mis-understood.  I will not write another book, but I will make a few comments.  The objective for any transmission line is to get a signal from one point to another point as efficiently as possible.  I define efficiency as "the best bang for the buck".  It is silly to use a waveguide to carry a low frequency signal, even though it has extremely low loss.  It is expensive, bulky, and almost impossible to bend.  This is an obvious example, but designing the "best" transmission line can become quite complicated.  In any case, all transmission lines have "characteristics", such as impedance, loss, velocity, power handling, size, cost, etc.  Knowing these characteristics can be quite valuable for the designer.
    Many people are familiar with common transmission lines, such as 50 ohm coax for the Amateur radio operator or 75 ohm coax used for cable television.