Wire transmission lines

Updated August 16, 2009

Click here to go to our page on skin depth

Click here to go to our page on the exact calculation of metal loss for coax

This is going to seem hodgepodge for a while. For now we will dump whatever info we can that has to do with wires used as transmission lines onto this page, then sort it out later. How about some contributions from the audience?

Wire over ground

We have a calculator that calculates impedance for this structure, click here!

Twin wires

Twisted pair

RF resistance of a wire

Resistive loss of a wirebond

We modified the coax spreadsheet (available in the download area) to calculate the metal loss of 1-mil diameter bond over frequency (does not include mismatch loss or radiation). It is very low, the plot is in dB/mm, a typical X-band bond is 1mm. The calculation also shows that at DC, 1-mil gold wire has 20 ohms resistance/meter, which
goes up with frequency.

The loss might actually be lower if you took into account that the impedance is transformed by the bondpads to something less than fifty ohms.