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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 9.7 dBi can be achieved at 28 MHz. [3] Because the placement and size of the parasitic reflector both depend highly on wavelength, each Moxon antenna functions properly on the frequency band ...
A modern high-gain UHF Yagi television antenna with 17 directors, and one reflector (made of four rods) shaped as a corner reflector. 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 ...
A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it has high directivity.
Wireless LAN (WLAN) channels are frequently accessed using IEEE 802.11 protocols. The 802.11 standard provides several radio frequency bands for use in Wi-Fi communications, each divided into a multitude of channels numbered at 5 MHz spacing (except in the 45/60 GHz band, where they are 0.54/1.08/2.16 GHz apart) between the centre frequency of the channel.
Omnidirectional antenna. In radio communication, an omnidirectional antenna is a class of antenna which radiates equal radio power in all directions perpendicular to an axis ( azimuthal directions), with power varying with angle to the axis ( elevation angle ), declining to zero on the axis. [ 1][ 2] When graphed in three dimensions (see graph ...
2.4 GHz helical antenna radiation pattern (NEC simulation) The Numerical Electromagnetics Code, or NEC, is a popular antenna modeling computer program for wire and surface antennas. It was originally written in FORTRAN during the 1970s by Gerald Burke and Andrew Poggio of the Lawrence Livermore National Laboratory.
Quarter-wave whip antenna on an FM radio for 88–108 MHz. Rubber ducky antenna on 446 MHz UHF walkie-talkie with rubber cover removed. VHF ground plane antenna. Mast radiator antenna of medium wave AM radio station, Germany. 'T' antenna of amateur radio station, 80 ft high, used at 1.5 MHz.
Directional antenna. A multi-element, log-periodic dipole array. A 70-meter Cassegrain radio antenna at GDSCC, California. 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 ...