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Occasionally, mechanical and electrical tilt will be used together in order to create greater beam tilt in one direction than the other, mainly to accommodate unusual terrain. Along with null fill, beam tilt is the essential parameter controlling the focus of radio communications, and together they can create almost infinite combinations of 3-D ...
In a radio antennas, the main lobe or main beam is the region of the radiation pattern containing the highest power or exhibiting the greatest field strength.. The radiation pattern of most antennas shows a pattern of "lobes" at various directions, where the radiated signal strength reaches a local maximum, separated by "nulls", at which the radiation falls to zero.
The axis of maximum radiation, passing through the center of the main lobe, is called the "beam axis" or boresight axis". In some antennas, such as split-beam antennas, there may exist more than one major lobe. The other lobes beside the main lobe, representing unwanted radiation in other directions, are called minor lobes.
At the equator (0° latitude), on the equinoxes, the sun angle is always 90° no matter the axial tilt, while on the solstices the minimum sun angle is equal to 90° minus the tilt. Therefore, greater tilt means a lower minimum for the same maximum: less total annual surface insolation at the equator.
Kikuchi lines in a convergent beam diffraction pattern of single crystal silicon taken with a 300 keV electron beam. The figure on the left shows the Kikuchi lines leading to a silicon [100] zone, taken with the beam direction approximately 7.9° away from the zone along the (004) Kikuchi band.
Each beam former has a receiver/exciter connected to it. A digital beam forming (DBF) phased array has a digital receiver/exciter at each element in the array. The signal at each element is digitized by the receiver/exciter. This means that antenna beams can be formed digitally in a field programmable gate array (FPGA) or the array computer.
Most antennas boresight axis is fixed by their shape and cannot be changed. However phased array antennas can electronically steer the beam, changing the angle of the boresight by shifting the relative phase of the radio waves emitted by different antenna elements, and even radiate beams in multiple directions (multiple boresights). [1]
Diagram of a typical 2D radar rotating cosecant squared antenna pattern. Diagram of a typical 3D radar, a judicious mix of vertical electronic beam steering and mechanically horizontal movement of a pencil-beam. Steered beam radars steer a narrow beam through a scan pattern to build a 3-D picture.