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A modern form of reflective array is the "bow tie" UHF television antenna. This example has two dipole driven elements in front of a grill reflector. The "bow-tie" dipoles, consisting of two V-shaped elements, have a larger bandwidth than ordinary dipoles, allowing the antenna to cover the wide UHF television band.
The IEEE defines the UHF radar band as frequencies between 300 MHz and 1 GHz. [3] Two other IEEE radar bands overlap the ITU UHF band: the L band between 1 and 2 GHz and the S band between 2 and 4 GHz. UHF television antenna on a residence. This type of antenna, called a Yagi–Uda antenna, is widely used at UHF frequencies.
An antenna array (or array antenna) is a set of multiple connected antennas which work together as a single antenna, to transmit or receive radio waves. [ 1 ] : p.149 [ 2 ] The individual antennas (called elements ) are usually connected to a single receiver or transmitter by feedlines that feed the power to the elements in a specific phase ...
Antenna diversity, also known as space diversity or spatial diversity, is any one of several wireless diversity schemes that uses two or more antennas to improve the quality and reliability of a wireless link. Often, especially in urban and indoor environments, there is no clear line-of-sight (LOS) between transmitter and receiver. Instead the ...
To connect balanced and unbalanced components, a two port device called a balun is used. A balun is a transformer that couples between balanced and unbalanced transmission line components. For example, to feed a dipole antenna from an unbalanced feedline like coaxial cable, the feedline is connected to the antenna through a balun. Without the ...
In same-band repeaters, isolation between transmitter and receiver can be created by using a single antenna and a device called a duplexer. The device is a tuned filter connected to the antenna. In this example, consider a type of device called a band-pass duplexer. It allows, or passes, a band, (or a narrow range,) of frequencies.
Slotted array UHF television broadcasting antenna. As shown by H. G. Booker in 1946, from Babinet's principle in optics a slot in a metal plate or waveguide has the same radiation pattern as a driven rod antenna whose rod is the same shape as the slot, with the exception that the electric field and magnetic field directions are interchanged; the antenna is a magnetic dipole instead of an ...
A directive antenna with moderate gain of about 8 dBi often used at UHF frequencies. Consists of a dipole mounted in front of two reflective metal screens joined at an angle, usually 90°. Used as a rooftop UHF television antenna and for point-to-point data links. Parabolic The most widely used high gain antenna at microwave frequencies and above.