We discuss the properties of Log Periodic Antennas on the previous Log Periodic Tooth Antenna page. Now we expand on that design further and introduce the Log-Periodic Dipole Antenna Array (sometimes abbreviated LPDA).
In Figure 1, we show the basic 5 element Log-Periodic Dipole Antenna Array
For the array in Figure 1, we use an expansion factor k=1.25. This means that each dipole is 25% longer than the one to the left of it, and the separation (d) between each dipole also increases by 25%. In addition, the log-periodic dipole array is arranged such that each element is fed out of phase to the element on either side. This is illustrated by the criss crossing feed pattern in Figure 1