Custom Line Options
Besides the manufactured cables listed in the “Cable Type” option, the following custom line options can be chosen, Fig. 1:
Custom lossless line
It is an ideal transmission line having zero losses, so only the nominal Z0 and velocity factor can be specified in this case.
Custom line low loss model
It is a transmission line where the nominal Z0, velocity factor and matched loss curve can be specified. To define the matched loss curve, two values of attenuation must be entered at two different frequencies, the second frequency being greater than the first one. AN-SOF will adjust a low loss model to obtain a curve of attenuation vs. frequency to perform the subsequent calculations. The real part of the characteristic Z0 will be equal to the nominal Z0 in the low loss model, which is a good approximation in many cases, especially for higher frequencies. The “true” velocity factor is also assumed to be equal to the nominal velocity factor.
Custom line RLGC model
It is a transmission line model where the losses are accurately considered by adjusting a matched loss curve to the table of attenuation vs. frequency in the cable datasheet. The K0, K1 and K2 constants must be entered in this case. The definition of K0, K1 and K2 considers that the frequency is in Hz and lengths are in meters (SI metric units). This option allows us to enter the K0, K1, K2 obtained from other transmission line calculators.