A simple method to determine the impedance of a loop antenna

Simple closed formula is given to determine the resistive part of the loop antenna input impedance. An equivalent transmission line is used to determine the reactive part of the input impedance for the same loop, and the antenna in both cases may have any regular configuration. This method has proved to be accurate for a loop perimeter up to
0.5 \lambda
for the resistive part and up to
0.8 \lambda
for the reactive part.