 So again good morning to everybody My name is Tomasz Walenski, and I'm a product manager with RF Elements, and I'll take you through this journey today So antennas have Actually, just let me let me remind one thing and that's if at any point during the presentation You have any questions feel free to write them down in into the question window in your webinar tool and I'll I'll answer them either during or at the end of the presentation So back to the topic antennas have many So-called textbook parameters and being a wisp Well, the question is do you need to know about each and every one of them? Well, of course not the question that the answer is no definitely not in the wisp industry There are only a few antenna parameters that you should really know and care about So in general, it's it's fair to say that Many of the antenna parameters are connected to one another and sometimes in quite a complex way so the parameters that are usually thought to Express the ability of an antenna to deal with the with the interference are our front-to-back ratio side-lobed level or Etsy masks now these you most likely know or at least heard about and The one we at RF elements believe is the most important one in terms of noise suppression is beam efficiency and in the following slides will we will explain why beam efficiency is the ratio of energy contained in the main loop to the total energy an antenna radiates So in other words, it it tells us what part of the radiated energy is going to the main loop So the higher the beam efficiency is the the more energy is contained in the main loop in other words Where we want it to be and vice versa Less energy is going everywhere else or in other words to the side lobes Now since side lobes do a lot of harm in the unlicensed wireless networks beam efficiency of antennas You're using is is something that's really worth knowing about and not only actually knowing about but also Make it a decision factor when thinking about how to deal with interference To give you a practical example This is the radiation pattern of a generic power bullet dish antenna, so if the beam efficiency is 40 percent These 40 percent of the power that are the antenna radiates go into the main loop Now how about the remaining 60 percent? Well the remaining energy goes everywhere else and Since everything outside the main loop is a side loop it goes into the side lobes note that All the side lobes are highlighted in this animation, so beam efficiency Includes all the side lobes of an antenna if you want to compare two antennas side by side in terms of Side lobe performance beam efficiency makes it extremely simple The higher number wins. It's simple as that. So for example The ultra horn had beam efficiency of 99 percent so only 1% of the power it radiates is in is in the side lobes and The a generic dish antenna has beam efficiency 40 percent So the remaining 60 percent of the energy it radiates is in the side lobes So 99 percent is more than 40 percent. That's clear clear as as the blue sky So therefore ultra horn is better antenna in terms of noise suppression probably Actually, probably the best on the market to be fair We should also look at the parameters you you might already know so front-to-back ratio is One of them and many manufacturers Included into their data sheets. So let's have a small recap of front-to-back ratio The conversion of thinking about front-to-back ratio is that if it is high it means an antenna is good for colocation So if the antennas are back-to-back and both have high front-to-back ratio, they will not interfere with each other The reality is that Front-to-back ratio does not mean an antenna is good for dense colocation in every possible scenario and setting It is simply Disconception it is important to understand this because next time you you might have a conversation about front-to-back ratio You can be sure that if anyone is saying that high front-to-back ratio means an antenna is great for dense colocation you you know that a person is either misinformed or we simply didn't go deep enough with the topic high front-to-back ratio means that The back low is small to be more precise the the low pointing in the opposite direction as the main low That one is small. It can also mean that a group of side lobes around the back lobe is small depending on the on a definition Or the way the front-to-back ratio was determined So front-to-back ratio is easy to understand looking at the radiation pattern of an antenna in this example We show the pattern of a directional patch array Front-to-back ratio is the difference between the gain of the main lobe and the back lobe which is pointing backwards in practice Front-to-back ratio is often determined based on the strongest side lobe from a plus minus 30 degree angle around the back lobe because possible manufacturing assembly or material imperfections Because of these imperfections the the back lobe might not be just a single lobe But it can be fractured and divided into several minor lobes around it and thus this this definition of front-to-back ratio is Is convention and adopted in many industries? Nevertheless back lobe is one of many side lobes antennas used in with wisp industry usually have So if that globe is one out of many side lobes, then it's probably not so important Now this is the typical error in Interpretation of front-to-back ratio. It doesn't say anything about the other side lobes So when two antennas are exactly back-to-back Colocated this is the rare kind of scenario where high front-to-back ratio can help to decrease interference level The the radios are working with But as I said before the the typical antenna used in wisp networks has as plenty of side lobes and the back lobe itself can be quite complex So as soon as there are more links on a tower or the Colocated antennas are not exactly back-to-back. You are looking at potential issues because of all the other side lobes High front-to-back ratio provides no protection Whatsoever in high noise environment so for urban and sub-urban areas With other wireless link and links in and the neighborhood or even on the same tower front-to-back ratio is simply irrelevant Now these other links may be yours or or competitors either way. They're using similar hardware to yours meaning their antennas are Most likely also have many side lobes that create noise Which is received through the rest of the side lobes Another parameter I want to I want to mention is side lobe level. In practical life It is it is similar to front-to-back ratio, but let's have a look at the at the details Side lobe level is the difference between the gain of the of the strongest side lobe and the main lobe As such it is more useful than the front-to-back ratio because at least it points out the strongest side lobe Which says about antenna performance in high-nose areas to a degree So if side lobe level is high the strongest side lobe is close to having the gain As the main lobe making it a poor antenna for WESP networks The issue with side lobe level is that it doesn't talk about all the side lobes So side lobe level is defined by the strongest side lobe which again is only one side lobe out of many and Also, it's defined at a single frequency Now since the side lobes are changing with frequency the noise level also changes with them So despite you know what the strongest side lobe is at single frequency It's not very useful in the bitter in the bigger picture since simple switching of a channel changes everything Side lobe level is therefore Similar metric to front-to-back ratio. It tells you what the strongest side lobe is at one frequency But nothing about the rest of the side lobes throughout the useful bandwidth of an antenna Which is the biggest issue with this two metrics in WESP networks all the side lobes matter To sum it up Not all the antenna parameters are practically useful for WESP networks Simply depends on the context the antenna is used in and in the end It's it's up to the users and mainly the manufacturers to responsibly look at each at each antenna parameter and Evaluate whether whether it's useful in the framework of WESP networks or not The conclusion for front-to-back ratio and side lobe level clearly says that these two are not so important They tell a very limited part of the story of side lobes You may have also heard about the Etsy masks which do to a degree They they also serve as a parameter that says how well antennas perform in terms of noise So let's have a closer look at at dose It is important to clarify that Etsy masks consider two principle cuts of the antenna radiation pattern So the azimuth and the elevation obviously so the masks consider two slices out of the whole 3d radiation pattern In terms of frequency the Etsy masks are observed at three frequency points the beginning the middle and the end of the spectrum an antenna works in Nevertheless the the rest of the spectrum, which is rather wide in case of WESP networks is is not included in Etsy definition starting with the polar plot you may know from antenna data sheets The antennas you're using and and redrawing it on an xy plot the Etsy mask is Is a line that says that the radiation pattern should stay below the mask So that an antenna can be declared compliant with a given Etsy norm So if it isn't the antenna is not compliant, which Yeah, is the case with with this particular example. We're using here The masks are easy to understand and to their credit they do consider the whole 360 degree circle of the radiation pattern, but unfortunately only two cuts of the whole 3d pattern and That at three frequency points of the whole spectrum an antenna works in So vast majority of the spectrum is simply not included. That's why in terms of the Interference suppression there. They're also not very useful So whenever you see an antenna being compliant with an Etsy form of any number You know that it does not bring much added value in terms of suppressing noise in WESP networks At RF elements, we strongly believe in doing the right thing for the customer and the industry So we looked in the textbooks as well and found out about beam efficiency Which is the most complete measure of sidelopes out there and when I say the most complete I'm I'm not just trying to push some marketing fluff through your ears and in the following slides We will clarify why So beam efficiency is the parameter WESP should have been looking for It gives the right answer to the question about sidelopes So despite you might have never heard about beam efficiency before Who at RF elements we we do what we believe is the best for the customer even if it means Bringing in something not considered before and which might be different from what other manufacturers are saying So if beam efficiency is the ratio of energy contained in the main loop to the energy The total energy on antenna radiates it is also a measure of sidelopes so we can get the percentage of the energy in the sidelopes by subtracting beam efficiency from the hundred percent of the overall energy and We can get beam efficiency of an antenna by measurement done in an unequipped chamber like the one you can see in the in this image now the antenna is attached to a rotary stage which rotates in in two axes and the radiation intensity is measured and Based on the measured data. We we can calculate beam efficiency If the model of an antenna is precise enough or if an antenna is is simple We we can use simulation software to do the same thing Obtain your radiation pattern and based on that we can calculate the beam efficiency So if beam efficiency is 40 percent So the 40 percent of the power antenna radiates goes into the main loop the remaining 60 percent Therefore must be in the sidelopes Know that all the sidelopes are highlighted so beam efficiency includes all the sidelopes of an antenna not just one or a slice of the radiation pattern, but the whole 3d pattern and It's similar case with the sector antennas here. You can see it's very easy to evaluate What's the amount of the energy that antenna radiates goes into the sidelope? If beam efficiency is 58 percent the rest of the energy in this case 42 percent is in the sidelopes So wasps use a wide chunk of spectrum But an antenna textbooks the beam efficiency is defined at a single frequency and For single polarization now This is the case for most textbook parameters and again it is up to the user and mainly the manufacturer to Consider whether one should care about the whole bandwidth or just a single frequency point Since the computational power is much more affordable nowadays than it was in the past we Can choose whether we you know, we need a wide band or a narrow band information at will So in with industry it makes perfect sense to average beam efficiency Over the whole bandwidth an antenna is working in because wasps use their antennas in a wide Frequency band, so it only makes sense that an antenna should perform well in the whole bandwidth So therefore we at our element we chose to extend the textbook definition of beam efficiency To a number that is the average of beam efficiency over the whole useful bandwidth of our antennas and Over both polarizations By doing this we we turn the textbook definition of beam efficiency into sort of a Super parameter if you will it is much more robust and more reliable measure of sideload performance than Then the single frequency and single polarization version so vast majority of antennas used for Sectorial coverage in with networks are you the patch erase or horns? The patch erase have many frequency dependent side loops So their beam efficiency values are around 60 percent depending on the quality of the manufacturing and design Now the RF elements horns both Symmetrical and asymmetrical have beam efficiency somewhere between 90 and 95 percent So less than 10 percent of the radiated power is in the side loops Now you can see other horns in this in this graph as well And this is to show that it takes considerable effort to design a horn such that it's Its beam efficiency is high So the stable and zero sideload performance is is not a given But we do put a lot of effort into our antennas to achieve high beam efficiency values similar Case is with the point-to-point antennas the patch erase are again at the at the bottom of the beam efficiency performance due to The many frequency dependent side loops collecting and transmitting noise hurting in any and every waste network Our dishes are are somewhat better and generally the bigger the dish the better the beam efficiency becomes If the antenna I mean that's under the condition that the antenna is carefully designed and and also well manufactured Now with any antenna though the the compromise is accepted at the at the design stage cannot be compensated by The manufacturing quality since the real-world results are with the antenna design are our best at best Approaching the design based on simulation results. Yeah So what is interesting here though is is the ultra horn so its beam efficiency is 99% So over the whole bandwidth of operation and over both polarizations the ultra the beam efficiency of ultra horn is is practically perfect Only 1% of the RF signal is in the sideloads So if you ever wondered if ultra horn was worth the extra cash compared to Any any kind of dish antenna you have a very clear answer here with 99% of beam efficiency It's probably the best performing antenna on the market in terms of noise suppression beam efficiency tells you Everything about sideload performance the higher it is the the better antenna performs So there you have it. I mean ditch the front of the ratio ditch sideload level or Etsy masks and Focus on the beam efficiency of an antenna when dealing with noise and not only is The beam efficiency most complete measure of sideload, but it's also extremely robust measure of sideload because Because of the averaging over the frequency bandwidth and both polarizations Since it rarely happens that a wireless link is situated in a completely isolated place The the interference is present almost everywhere so the noisier the environment and The the more important the beam efficiency of an antenna becomes because the higher the beam efficiency the better the noise isolation so in the following section I Right So the the most let's say short the shortest practical implication of high beam efficiency is that you know The antenna has low silos which results into a good SNR the radio is working with and in the end It means higher throughput. So we can sum up the effect of the beam efficiency of high beam efficiency Of antennas into one statement. It means it equals higher throughput so in a In a sector with no other links in the area you you don't mind the sidelopes really but it's the number of sectors grow Grows the the sidelopes cause the noise floor to rise so higher noise floor equals to lower throughput the beam efficiency of battery sectors is on the order of 60 percent so the 40 percent of the energy they is is In the sidelopes and the sidelopes collect and transmit interference to other links within yours But also competitors network, obviously, so a low beam efficiency equals to lower throughput and Consequently more unsatisfied customers Low beam efficiency of dish antennas works in a similar way The sidelopes collect the noise from its surroundings and transmitted to all neighboring links So whether it's a it's a backhaul link or a distant narrow sector the the beam efficiency around 45 percent means low throughput in high noise areas replacing the low beam efficiency beam efficiency patch erase sector by horn antennas with beam efficiency up to 99 percent The noise level in the urban and high density areas is effectively avoided So because I've been my efficiency means no sidelopes and no sidelopes means no interference resulting into a higher It's as simple as that So addressing the most pressing problem of with networks becomes much more straightforward On the one advice here use antennas with high beam efficiency high beam efficiency equals high throughput the radio manufacturers are of course also trying to help with With the noise of course. So the GPS synchronization Which ensures that the radios in your network transmit and receive at the same time protects you from self interference, but It does not protect you from The sidelopes of the competitors antennas. So high beam efficiency Antenna ensures that you don't have to worry about the interference at all. It does not receive it So you don't need to try to deal with with interference in the first place So beam efficiency is a very practical antenna parameter where before the discussion about the sidelopes was So it's sort of limited to you know, the comparisons have typed like okay This antenna has many sidelopes this antenna has little sidelopes or this antenna has this antenna doesn't have beam efficiency Provides a number from zero to 100 percent, which makes it super easy to compare sideload performance So now, you know that front to back ratio and or side lobe level are the parameters that are not so important More useful in Wisp industry because they only consider one side lobe out of many and Antenna might have so beam efficiency includes all the sidelopes, which makes it's very useful metric Including all the sidelopes removes any sort of ambiguity. You can be sure that this metric is reliable and always Ask whether a parameter is single frequency or white band in Wisp industry white band is simply a must Because the spectrum is shared by many and therefore white band white band performance is simply vital So RF element addition to the beam efficiency definition is to is to average Over both polarizations and whole antenna bandwidth now you cannot do better than that period That's why beam efficiency is the ultimate measure to judge antennas by in Wisp industry And it is a tool in your hands to make a better decision for for your business So please use it and and keep asking for it to make it easy for you We we added beam efficiency of our antennas into all our data sheets And we are we're transparent manufacturer and want to provide our customers with the information that is important to for them So education is also important part of our awareness activities. It is one out of Out of many of our first in the Wisp industry now things that We at RF elements can put on display Is that our idea is that? Only an educated customer can make qualified decisions And we're also very open about myth-busting because there there are many myths out there and misconceptions about all kinds of wireless concepts That and consequently can create a lot of problems in Wisp networks You've probably already noticed that we have our online Forum called RFELAP.com if you haven't it's a forum where you can It's the most direct way to contact us contact us and you can ask questions about our products or Or search through the questions that have been already asked There's a lot of recordings of webinars such as this one And also other recordings and of course we can find us also on the On the social other social media platforms So eventually just a trademark disclaimer so that it's clear that we're using third parties Trademarks only to reference compatibility with our products