In an antenna array made of multiple conductive elements, a driven element or active element is electrically connected to the receiver or transmitter while a parasitic element is not.
Yagi antenna for UHF TV reception with 22 parasitic elements; 4 reflectors attached to the vertical bracket at left, and 18 directors attached to the horizontal beam at right. The driven element is attached to the black box next to the reflectors. The antenna is most sensitive to radio waves coming from the right, parallel to the antenna's axis.
Maszt radiowy w Konstantynowie
Log-periodic antenna
Videos
A log-periodic antenna, also known as a log-periodic array or log-periodic aerial, is a multi-element, directional antenna designed to operate over a wide band of frequencies. It was invented by John
Driven and parasitic elements
…assumptions, two elements spaced λ/4 and carrying equal-amplitude currents with a 90° relative phase can produce a cardioid-type array factor. A log-periodic antenna (LPDA) consists of many dipole elements of decreasing length, all of which are driven. However, because they are different lengths, only one of the…
Log-periodic antenna, 400–4000 MHz
Log-periodic antenna, 250–2400 MHz
Log-periodic mounted for vertical polarization, 140–470 MHz
LP television antenna 1963. Covers 54–88 MHz and 174–218 MHz. Slanted elements were used because on the upper band they operate at the third harmonic.