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A Yagi–Uda antenna, or simply Yagi antenna, ... Yagi demonstrated a proof of concept, but the engineering problems proved to be more onerous than conventional systems.
An antenna may have more than one driven element, although the most common multielement antenna, the Yagi, usually has only one. For example, transmitting antennas for AM radio stations often consist of several mast radiators , each of which functions as a half-wave monopole driven element, to create a particular radiation pattern .
However, a Yagi with the same number of elements as a log-periodic would have far higher gain, as all of those elements are improving the gain of a single driven element. In its use as a television antenna, it was common to combine a log-periodic design for VHF with a Yagi for UHF, with both halves being roughly equal in size.
[ab] The simple antennas used to make a Yagi-Uda can either all be linear or bent linear antennas, or all loops (a quad antenna) or (rarely) a mixed combination of loops and straight-wire antennas. Yagi–Udas are used for rooftop television antennas, point-to-point communication links, and long distance shortwave communication using skywave ...
A quad antenna is a type of directional wire radio antenna used on the HF and VHF bands. A quad is a Yagi–Uda antenna ("Yagi") made from loop elements instead of dipoles: It consists of a driven element and one or more parasitic elements; however in a quad, each of the loop elements may be square, round
Hidetsugu Yagi (八木 秀次, Yagi Hidetsugu, January 28, 1886 – January 19, 1976) was a Japanese electrical engineer from Osaka, Japan. When working at Tohoku Imperial University , he wrote several articles that introduced a new antenna designed by his assistant Shintaro Uda to the English-speaking world.
Patch antenna gain pattern. A directional antenna or beam antenna is an antenna which radiates or receives greater radio wave power in specific directions. Directional antennas can radiate radio waves in beams, when greater concentration of radiation in a certain direction is desired, or in receiving antennas receive radio waves from one specific direction only.
A VHF/UHF antenna combines two antennas feeding the same feedline mounted on the same support boom. More extended elements that pick up VHF frequencies are located at the back of the boom and often function as a log-periodic antenna. Shorter elements that receive the UHF stations are located at the front of the boom and often function as a Yagi ...