In antenna engineering, sidelobes are the lobes (local maxima) of the far field radiation pattern of an antenna or other radiation source, that are not the main lobe. The radiation pattern of most antennas shows a pattern of " lobes " at various angles, directions where the radiated signal strength reaches a maximum, separated by " nulls ...

Sidelobes are an unfortunate reality of all directional antennas. They are a consequence of nature and are directly related to diffraction effects in light – and there are similar effects in sound and water waves. Diffraction occurs whenever there is a sharp discontinuity in a …

In this section, we begin with a discussion of antenna sidelobes and the effect of tapering across an array. Tapering is simply the manipulation of the amplitude contribution of an individual element to the overall antenna response. In Part 1, no tapering was applied and the first sidelobes were –13 dBc as seen in the figures.

Side lobe return accounts for the solid character of the display pattern from non-precipitating targets at close range, usually called ground clutter. This, of course, makes it very difficult at times to separate precipitation from non-weather targets within the ground clutter pattern.

Sidelobes are another problem, which we learned can be mitigated by tapering the gain of the array toward the edges. However, tapering comes at the expense of widening the beam, again requiring more elements. Phase shifter resolution can introduce quantization sidelobes that also must be factored into the antenna design.

For antennas used as receivers, sidelobes make the antenna more vulnerable to noise from nuisance signals coming far away from the transmit source. For transmit antennas communicating classified information, sidelobes represent security vulnerability, as an unintended receiver may pick up the classified communication.

If the pattern in a particular plane has more than a front lobe and a back lobe, the other lobes are called side lobes. The maximum side lobe level (SLL), relative to the main lobe, is sometimes of interest. Aside from these feature-based parameters, there is a more basic measure of directionality called directivity. It is defined as.

2022年11月28日 · In antenna engineering, side lobes or sidelobes are the lobes (local maxima) of the far field radiation pattern of an antenna or other radiation source, that are not the main lobe. The radiation pattern of most antennas shows a pattern of "lobes" at various angles, directions where the radiated signal strength reaches a maximum, separated by ...

However, all radar antennas naturally have “sidelobes” – additional beams, away from the main beam, which radiate and receive some fraction of the radar’s energy. Normally, a target return will only show up in the radar video when the antenna is pointing at the target, to within about one width of the main lobe.

From Fig. 3.3 and Eq. (3.4), we see that the main-lobe width is radian, and the side-lobe level is 13 dB down. Since the DTFT of the rectangular window approximates the sinc function (see (3.4)), which has an amplitude envelope proportional to (see (3.7)), it should ``roll off'' at approximately 6 dB per octave (since ).