This is a Java applet which calculates the dimensions and spacings of the elements needed to build a log periodic antenna, given tao, sigma and the lower and upper cutoff frequencies.
All lengths and distances are given in meters. Look below for a diagram and a brief explanation describing what are all these numbers and parameters...
 | In a nutshell, The log periodic is a broadband antenna whose caracteristics vary as a periodic function of the logarithm of the frequency (with period Log(Tao)). As Tao approaches unity, we can neglect these response variations and regard the antenna as "frequency independant". Sigma is a spacing factor, and together with Tao, determine the directivity of the antenna. |