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A reconfigurable antenna is an antenna capable of modifying its frequency and radiation properties dynamically, in a controlled and reversible manner. [2] In order to provide a dynamic response, reconfigurable antennas integrate an inner mechanism (such as RF switches, varactors, mechanical actuators or tunable materials) that enable the intentional redistribution of the RF currents over the ...
In a reconfigurable transmitarray, the focusing direction is determined by electronically controlling the phase shift through each unit cell. [13] This enables the beam to be steered towards the user. Electronic reconfiguration can be achieved by several possible methods. Radiation pattern for a planar transmitarray. [1]
Simulated and measured radiation patterns of a reflectarray antenna ... A reconfigurable reflectarray has unit cells whose phase can be electronically controlled in ...
The radiation pattern of such an antenna consists of a strong beam in one direction, the main lobe, plus a series of weaker beams at different angles called sidelobes, usually representing residual radiation in unwanted directions. The larger the width of the antenna and the greater the number of component antenna elements, the narrower the ...
The far-field pattern of an antenna may be determined experimentally at an antenna range, or alternatively, the near-field pattern may be found using a near-field scanner, and the radiation pattern deduced from it by computation. [1] The far-field radiation pattern can also be calculated from the antenna shape by computer programs such as NEC.
Omnidirectional radiation patterns are produced by the simplest practical antennas, monopole and dipole antennas, consisting of one or two straight rod conductors on a common axis. Antenna gain (G) is defined as antenna efficiency (e) multiplied by antenna directivity (D) which is expressed mathematically as: G = e D {\displaystyle G=eD} .
When driven in phase, the radiation pattern of the reflective array is a single main lobe perpendicular to the plane of the antenna, plus several sidelobes at equal angles to either side. The more elements used, the narrower the main lobe and the less power is radiated in the sidelobes.
The term "phased array" is also used to a lesser extent for unsteered array antennas in which the phase of the feed power and thus the radiation pattern of the antenna array is fixed. [8] [11] For example, AM broadcast radio antennas consisting of multiple mast radiators fed so as to create a specific radiation pattern are also called "phased ...