Inside Wireless: Side Lobes

Wondering what side lobes are and if they are harmful to your WISP network? In this short video you will learn about Side Lobes, Front to Back (FtB) ratio and side lobe level (SLL).

The radiation diagram of an antenna tells us how strongly antenna radiates in any direction. The main lobe has the highest gain and most antennas have only one main lobe.

All the lobes other than the main lobe are called side lobes. The size of sidelobes depends on the type, size, and construction of an antenna. It’s important to understand that through side lobes, antenna transmits but also receives the signal from unwanted directions.

Requirements on the sidelobes vary depending on the application, but generally, we can say side lobes are a no-no. For point to point applications, we want to deliver as much energy as possible to a single point, and any side lobe means part of it is wasted. For area coverage applications - like sector antenna - we want to avoid all side lobes outside the main lobe.

Antenna side lobes are especially harmful in fixed wireless access networking. Any signal radiated to unwanted direction is noise to any other radio in the area. And vice versa, any signal received from unwanted direction is noise to your own radio.

Side lobes increase the noise level and therefore should be avoided at all costs to ensure sustainable use of the spectrum. Whether the spectrum is licensed or unlicensed, does not matter, however, the point of no return is achieved quicker in the unlicensed bands due to uncontrollable amount of devices deployed.

Side lobes are often judged by so-called Side Lobe Level or Front to Back ratio. Side Lobe Level is the difference between the gain of the main lobe and the gain of the strongest sidelobe. Front to Back ratio is the difference between the gain of the main lobe and the back lobe. Most antenna manufacturers often misuse Front to Back ratio as the measure of sidelobe suppression, while it only gives information about the gain of the back lobe. It says nothing about the rest of the side lobes antenna might have.

0:00 Introduction
0:14 Radiation Diagram
0:24 Side Lobes
0:42 Requirements
1:07 Avoid Side Lobes
1:27 Side Lobe Level (SLL)
1:32 Front to Back Ratio
1:47 Examples

#RFelements #InsideWireless #SideLobes #SideLobeLevel #Antennas #AntennaTheory #WISP #SaveSpectrum #RejectNoise #GrowSmart #UbiquitiNetworks #CambiumNetworks #MimosaNetworks #Mikrotik

[AWAKENBOY]

Excellent explanation about side and main lobes. Could you please explain the Sub love supression and how that impacts dynamic elevation scanning range?

[danielmsheliza]

Love how concise and clear this video is. Thank you so much!

[jayglinoga]

Hi! Nice videos. Do you have any video regarding interference calculations?

[ShayMoshe]

Hey, can you explain why the "point of no return" is achieved quicker?

[andreac]

Hello! in case of multiple horns mounted on the same pole, which is the minimum installation distance you suggest between an horn and an other one? Thanks

[rachelcarre]

Sorry, stupid question. Will the signal in the slide lobe still be the same frequency as the main lobe? Or will it vary?

[GroverSecuritySystems]

Hello RF elements. Your videos are constanctly the best on the topic of Antennas and signal.
I would like to ask if there is a device (or software) that could visually present to the user the main and side lobes, and general the radiation pattern of an antenna? How to make visible something which is not ?!
Thank you!

[phanidharkumar]

Sir, can you please tell what exactly is a grating lobe and how to avoid it?

[alteahjeddavalsantos]

You talk like you have friends waiting to u. You talk faster.

[alexmuhania]

you are talking FAST, try to slow down and deliver a clear point, you have a great contents but you are not delivering wisly .