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A typical radiation pattern of phased arrays whose inter-element spacing is greater than half a wavelength, hence the radiation pattern has grating lobes.. For discrete aperture antennas (such as phased arrays) in which the element spacing is greater than a half wavelength, a spatial aliasing effect allows plane waves incident to the array from visible angles other than the desired direction ...
Grating lobes are a special case of a sidelobe. In such a case, the sidelobes should be considered all the lobes lying between the main lobe and the first grating lobe, or between grating lobes. It is conceptually useful to distinguish between sidelobes and grating lobes because grating lobes have larger amplitudes than most, if not all, of the ...
These equations can be solved to predict the nulls, main lobe, and grating lobes of the array. Referring to the exponents in the array factor equation, we can say that major and grating lobes will occur at integer , =,,, … solutions to the following equations: [4] [41] [page needed]
Now, suppose that the excitation coefficients are positive real variables. In this case, always in the domain of , the array factor magnitude has a main lobe with maximum value at =, called mainlobe, several secondary lobes lower than the mainlobe, called sidelobes and mainlobe replicas called grating-lobes. Grating lobes are a source of ...
Roche lobe, the region of space around a star in a binary system within which orbiting material is gravitationally bound to that star; Sidelobe, an identifiable segment of an antenna radiation pattern Grating lobe, a sidelobe that is much higher than all other side lobes, approximately the same as the main beam — exists only in phased arrays
Since side lobes of the Airy disk are responsible for degrading the image, techniques for suppressing them are utilized. If the imaging beam has Gaussian distribution, when the truncation ratio (the ratio of the diameter of the Gaussian beam to the diameter of the truncating aperture) is set to 1, the side-lobes become negligible and the beam ...
This means the grating strength can be used to set the bandwidth. The grating length, effectively , can then be used to set the peak reflectivity, which depends on both the grating strength and the grating length. The result of this is that the side-lobe strength cannot be controlled, and this simple optimisation results in significant side-lobes.
The grating profile is the function of the reflectance or transmittance perpendicular to the lines. This function is generally a square wave, in that every transition between lines is abrupt. A grating can be defined by six parameters: Spatial frequency is the number of cycles occupying a particular distance (e.g. 10 line pairs per millimeter ...