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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 ...
In antenna theory, a phased array consists of many small antennas, positioned in an array, next to each other. Instead of sending a radio wave with one antenna, a computer system can shift the phase of the original wave by fractions of a wavelength for each individual antenna in the array.
Digital antenna array (DAA) is a smart antenna with multi channels digital beamforming, usually by using fast Fourier transform (FFT). The development and practical realization of digital antenna arrays theory started in 1962 under the guidance of Vladimir Varyukhin ( USSR ).
What's more, a phased array can be made "steerable", that is, by changing the phases applied to each element the radiation pattern can be shifted without physically moving the antenna elements. Another common array antenna is the log-periodic dipole array which has an appearance similar to the Yagi (with a number of parallel elements along a ...
Smart antennas (also known as adaptive array antennas, digital antenna arrays, multiple antennas and, recently, MIMO) are antenna arrays with smart signal processing algorithms used to identify spatial signal signatures such as the direction of arrival (DOA) of the signal, and use them to calculate beamforming vectors which are used to track and locate the antenna beam on the mobile/target.
Parasitic arrays are a specific type of endfire array that consist of multiple antennas, usually dipoles, with one driven element and the rest parasitic elements, which draw power from the radiated beam and then re‑radiate that signal power along the line of the antenna rods. It is parasitic arrays that are the closest RF analogs of compound ...
A Butler matrix can also feed a circular array giving 360° coverage. A further application with a circular antenna array is to produce omnidirectional beams with orthogonal phase-modes so that multiple mobile stations can all simultaneously use the same frequency, each using a different phase-mode. [7]
An antenna array consisting of two such antennas, one above the other and driven in phase has a gain of up to 17 dBi. Being log-periodic, the antenna's main characteristics ( radiation pattern , gain, driving point impedance ) are almost constant over its entire frequency range, with the match to a 300 Ω feed line achieving a standing wave ...