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The Yagi-Uda antenna, also known as Yagi antenna, catches TV and radio signals. Invented by Japanese scientists Hidetsugu Yagi and Shintaro Uda in the 1920s, it's great at sending signals in one direction. Useful for improving TV signals, ham radios, radar, and satellite communication.
Yagi–Uda antenna. Drawing of Yagi–Uda VHF television antenna from 1954, used for analog channels 2–4, 54–72 MHz (U.S. channels). It has five elements: three directors (to left) one reflector (to right) and a driven element which is a folded dipole (double rod) to match the 300 Ω twin lead feedline.
Below picture shows the yagi uda antenna design diagram. Yagi Uda Antenna Structure. In the design of the Yagi antenna, the structure which is in the form of a center rod where the components are placed is termed a boom.
If you’ve ever seen a spindly antenna on top of someone’s house, it’s probably a Yagi-Uda! Its ease of construction and the cheapness of materials combined with the amount of gain provided makes it an attractive option for DIY projects and prototypes.
The Yagi-Uda antennas typically operate in the HF to UHF bands (about 3 MHz to 3 GHz), although their bandwidth is typically small, on the order of a few percent of the center frequency. You are probably familiar with this antenna, as they sit on top of roofs everywhere.
The Yagi-Uda Antenna is a directional antenna usually used for transmitting or receiving radio frequency (RF) waves. It was invented in 1926 by Shintaro Uda. The antenna is named after Japanese inventor Hidetsugu Yagi. They send out their signals in a single, specified direction.
Figure: The spatial behavior of the electric (solid) and magnetic (dashed) fields of a linearly (vertical) polarized wave for a fixed instant of time. A radiation pattern (antenna pattern) is a graphical representation of the radiation (far-field) properties of an antenna.
The design of a Yagi-Uda antenna is actually quite simple. Because Yagi antennas have been extensively analyzed and experimentally tested, the process basically follows this outline: Look up a table of design parameters for Yagi-Uda antennas. Build the Yagi (or model it numerically), and tweak it till the performance is acceptable.
A Yagi-Uda antenna is formed by a combination of 3 major elements i.e., driven element, reflector and directors. These are basically designed to operate in very high and ultra-high frequency bands and offers the operating frequency ranging between 30 MHz to 3 GHz.
Typical characteristics/parameters: Coaxial using a Gamma match, Omega match, or modified Gamma match at the driven element. Twin-lead using a T-match at the driven element or with a folded dipole as the driven element. Pre-determined designs are available.