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It is a two element Yagi-Uda antenna with folded dipole elements, and no director(s). Because of the folded ends, the element lengths are approximately 70% of the equivalent dipole length. The two-element design gives modest directivity (about 2.0 dB ) with a null towards the rear of the antenna, yielding a high front-to-back ratio : Gain up to ...
Consider a Yagi–Uda consisting of a reflector, driven element, and a single director as shown here. The driven element is typically a 1 ⁄ 2 λ dipole or folded dipole and is the only member of the structure that is directly excited (electrically connected to the feedline). All the other elements are considered parasitic. That is, they ...
Drawing of a Yagi–Uda VHF television antenna used for analog channels 2–4, 54–72 MHz (U.S. channels). It has four parasitic elements: three directors (to left) and one reflector (to right) and one driven element which is a folded dipole (double rod) connected to a 300 Ω twin lead feedline down the mast to the television set.
Dipole antenna used by the radar altimeter in an airplane. Animated diagram of a half-wave dipole antenna receiving a radio wave. The antenna consists of two metal rods connected to a receiver R. The electric field (E, green arrows) of the incoming wave pushes the electrons in the rods back and forth, charging the ends alternately positive ...
A corner reflector antenna is a type of directional antenna used at VHF and UHF frequencies. [1][2] It was invented by John D. Kraus in 1938. [3][4] It consists of a dipole driven element mounted in front of two flat rectangular reflecting screens joined at an angle, usually 90°. [1] Corner reflector antennas have moderate gain of 10–15 dB ...
T2FD antenna. A 20-meter-long T²FD antenna, covering the 5-30 MHz band. The Tilted Terminated Folded D ipole (T²FD, T2FD, or TTFD) or Balanced Termination, Folded Dipole (BTFD) - also known as W3HH antenna - is a general-purpose shortwave antenna developed in the late 1940s by the United States Navy. [1][2] It performs reasonably well over a ...
The J-pole antenna is an end-fed omnidirectional half-wave antenna that is matched to the feedline by a shorted quarter-wave parallel transmission line stub. [5] [1] [6] For a transmitting antenna to operate efficiently, absorbing all the power provided by its feedline, the antenna must be impedance matched to the line; it must have a resistance equal to the feedline's characteristic impedance.
The several dipole arms extend away (⚞⚟ ⪫⪪ ⫸⫷) from the common central connection point of the combined antenna. [t] Fan monople A fan monopole, or multi-monopole is a half of a fan dipole: It combines several different-sized monopole antennas, all sharing the same feedpoint, with each sized to transmit well on a different band or ...