 Good morning to everyone. I'm Tomasz Wolenski and I'm a Product and Marketing Manager at RF Elements. And today we'll give you a presentation on Beam Efficiency, which at RF Elements we consider the most important antenna parameter in WISP networks. And that's regardless if they're licensed or unlicensed. So let's get to the topic. So antennas have many parameters, which you can also look at so-called textbook parameters. And being a WISP, you might be asking yourself a question, well, do I need to know about each and every one of them? And no, of course you don't. In fact, nobody does. And in the WISP industry, there are only a few antenna parameters that you should really know and care about. And it's fair to say that many of these parameters are connected to one another and sometimes actually in quite a complex way. So the parameters of the antennas that are usually thought to express the ability of an antenna to deal with interference are front-to-back ratio, side-lob level, or maybe also no Etsy masks. And these are those you most likely know or at least heard about. The one we at RF Elements believe is the most important one in terms of noise suppression is beam efficiency. Beam efficiency is the ratio of the energy contained in the main loop to the total energy an antenna radiates. In other words, it tells us what part of the radiated energy is going into the main loop. And if we know what part of the energy is in the main loop, the rest must be in the side loops because any loop outside the main loop is a side loop. So the maximum value of beam efficiency is 100%, which is the ideal situation. And the smaller the beam efficiency is, the more side loops an antenna has. And since antenna side loops do not do a lot of harm in the WISP networks, WISPs should really avoid antennas with a lot of side loops or, in other words, low beam efficiency at all costs. Now, the higher the beam efficiency of the antenna you use is, the better your network will perform and the end users will also perceive the services you provide to them in a better way. So beam efficiency is an antenna parameter, not only to know about, but actually also factor it in when deciding on how to deal with interference issues you might be having. To give a practical example, so here you see the radiation pattern of a parabolic dish antenna. Now, if its beam efficiency is 40%, this means that this 40% of the power this antenna radiates goes into the main loop. Now, the remaining 60% goes everywhere else. And since everything outside the main loop is a side loop, it must be in the side loops. And note that all the side loops are highlighted here. And that's not a coincidence or just marketing gimmick. So beam efficiency really does include all the side loops an antenna has. And if you want to compare two antennas in terms of side loop performance, beam efficiency makes it extremely simple and the higher number wins. So in this example, the ultra horn has beam efficiency of 99%. So it's only 1% short of perfection. On the other hand, on the right side, the generic dish antenna has beam efficiency of 40%. So the remaining 60% of the energy it radiates is in the side loops. And 99% is clearly more than 40%. And then that's why ultra horn is way better antenna in terms of noise suppression. In our opinion, it's actually the best on the market. But to be fair, let's give a chance also to the established knowledge and let's look at the parameters you might already know. So front-to-back ratio is one of them. And many manufacturers included into their antenna data sheets or actually even build a marketing messages around it. So let's have a small recap of the front-to-back ratio. The conventional thinking about front-to-back ratio is that if it's high, it means an antenna is good for dense colocations. 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 setting. This is a big misconception. It is important to understand this because next time you might be having 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 colocation, you know that the person is either misinformed or simply just didn't go deep enough into the topic. High front-to-back ratio means that the back-lobe is small and this is the low pointing in the opposite direction as the main lobe. It can also mean that a group of side lobes around the back-lobe is small, depending on the definition or the way the front-to-back ratio was determined. So front-to-back ratio is really easy to understand. Now looking at the radiation pattern of an antenna, in this example, we show the pattern of a directional patch array antenna. The 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 direction because of possible manufacturing, assembly, or material imperfections. And because of these imperfections, the back-lobe might not be just a single nice lobe, but can be divided and fractured into several smaller and minor lobes around it. And that's the plus-minus 30-degree angle definition that just simply makes sense to account for all these possible imperfections. Nevertheless, a back-lobe is one of many side lobes antennas used in whisper industry typically have. So if back-lobe is one out of many side lobes, then it's probably not so important, isn't it? This is the typical error in the interpretation of the front-to-back ratio. It doesn't say anything about the rest of the side lobes. It just considers that one back-lobe. And when two antennas are exactly back-to-back, which, let's be honest, is a rare kind of scenario where high front-to-back ratio can help to decrease the interference level of the radio C. But, as I said before, the typical antenna used with networks has 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 collocated antennas are not exactly back-to-back, you're looking at a potential issue because of all the other side lobes that are most likely present. High front-to-back ratio provides absolutely no protection in high noise environments. So for urban and suburban areas with other wireless links in the neighborhood or even in the same tower, front-to-back ratio is irrelevant. These other links may be yours or your competitors. Either way, they're using similar hardware to yours, meaning that their antennas most likely also have many side lobes that create the noise, receive the noise through the rest of the side lobes, and so on and so on. Another parameter I want to briefly mention is the side lobe level. So in practical life, it is similar to front-to-back ratio, unfortunately, but again, let's have a look at the details. Side lobe level is the difference between the gain of the strongest side lobe and the main lobe. Now, as such, it is more useful than front-to-back ratio because it at least points out the strongest side lobes, which says about antenna performance in high noise areas to a degree. Now, if side lobe level is high, the strongest side lobe is close to having the same gain as the main lobe, making it a very poor antenna for WISP networks. The issue with side lobe level is that it does not talk about all the other side lobes just like the front-to-back ratio. And side lobe level is defined by the strongest side lobe, which again is only one side lobe out of many and defined at a single frequency on top of that. Now, since the side lobes are changing with frequency, the noise level also changes with them. So despite you know when the strongest side lobe is at a single frequency, it is not very useful in the bigger picture since simple switching of the channel changes everything you see. 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 spectrum of an antenna, which is the biggest issue with these metrics. In WISP networks, all side lobes matter, not just one and not just at one single frequency. So to sum it up, not all the antenna parameters are practically useful for WISP networks. It simply depends on the context an antenna is used in. And in the end, it is up to the user and actually also the manufacturer to responsibly look at each antenna parameter and evaluate if it's useful in the framework of WISP networks or not. And the conclusion of the front-to-back ratio and side lobe level clearly says that these two parameters are really not important. If anything, they tell a very limited part of the story about the side lobes. And if you're wondering why WISP antenna manufacturers use them, well, my personal guess would be it's simply the remnant of the times when these parameters were the only ones that were easy to determine without overbearing computational power, which might not have been available at the time. Okay, you may also know about the Etsy masks. So you may know about these already as well, which the Etsy masks to a degree also serve as a parameter that says how well antennas perform in terms of noise. So let's have a closer look at those. It is important to clarify that the Etsy masks consider just two principle cuts of the antenna radiation pattern, which you can see right now. So the azimuth and elevation. So these masks consider the two slices from the whole 3D radiation pattern, which again is rather incomplete measure from the point of view of the whole radiation pattern and all the side lobes that matter in WISP networks. The Etsy masks are observed at three frequency points. That's the official definition. So the beginning, the middle and the end of the spectrum and antenna works. And nevertheless, the rest of the spectrum, which is rather wide in case of WISP networks is not included in the Etsy mask definition. So how does one get to the Etsy masks and how do they look like? Starting with the polar plot, you may know from the antenna data sheets and redrawing it on an XY plot. The Etsy mask is the blue dashed line, which you'll see in a moment. And which says that the radiation pattern should stay below the mask so that an antenna can be declared compliant with a given Etsy norm. So this mask is changing with angle as is obvious from the picture. So it has a few steps visible from the plot. And if the radiation pattern does not stay below the mask, the antenna is not compliant, which is the case for this particular example we're showing. So the masks are easy to understand. And to their credit, they do consider the whole 360 degrees circle of the radiation pattern. But unfortunately, only two cuts of the whole 3D radiation pattern at three frequency points of the whole spectrum of an antenna that an antenna can work in. So the vast majority of the spectrum is not included. Now, therefore, in terms of the interference suppression, they're not very useful parameter. So whenever you see an antenna being compliant with an Etsy norm of any kind, know that it does not bring much added value in terms of the noise suppression in Wisp networks. At our developments, we strongly believe in doing the right thing for the customer and the industry. So we looked into the textbook about the antennas as well and found about beam efficiency, which is the most complete measure of side loops out there if it's used well, if it's used the right way. And when I say the most complete, I'm not just pushing some marketing fluff through your ears. And in the following slides, you will see why. So beam efficiency is the parameter Wisp should have been looking for since the dawn of this industry. Now, it gives the right answer to the question about side loops. So despite you might have never heard about it before, at our developments, we do what we believe is the best for the customer. And even if it means bringing in something not considered before, which might be different from what other manufacturers are saying. Now with the beam efficiency is a ratio of energy contained in the main loop to the total energy and antenna radiates. It is also a measure of side loops as we explained before. So we can get the percentage of the energy that the side loops contain by subtracting the beam efficiency from 100%. And actually, this really kind of gives you a very straightforward path to when you have a discussion about antennas and say like, oh, this antenna has a lot of side loops, this antenna doesn't have any. Well, now you're not any more relegated or you don't need to just say these like vague statements that one antenna doesn't have and the other has a lot of side loops. Now you have a physically measurable variable that says clearly what amount of the energy antenna radiates is in the side loops. So the discussion will be probably quite very short thanks to the beam efficiency. And we can get the beam efficiency of an antenna in several ways. One of them being measurement done in an equate chamber, like the one you can see in the image, where the antenna is attached to a rotary stage which rotates in two axes and can measure the radiation pattern of an antenna in 3D space. So based on the measurement of the radiation pattern, the beam efficiency of an antenna can be calculated. If the model of an antenna is precise enough or an antenna is simple, we can use simulation software to do the same thing to obtain the radiation pattern and based on that, the beam efficiency can be calculated. So if you see is 40%, the 40% of the power radiates is in the main loop and the remaining 60% is therefore in side loops. And again, just to emphasize the fact that we consider all or the beam efficiency definition we as we use it considers the whole 3D radiation pattern. So it includes all the side loops in every possible direction, not just one side loop, meaning the back loop like front of the ratio or the side loop level, which really give a very limited information about the side loops. Similarly with the sector antennas, here you see an example of a patch or a sector antenna with beam efficiency of 58%. So which means that 42% of the energy radiates is in the side loops. And WISPs use a wide chunk of spectrum, but in antenna textbooks, beam efficiency is actually also defined at a single frequency and then for single polarization. Now this is the case for most textbook parameters. And again, it is up to the user and the manufacturers as well to consider where the one should care about the whole bandwidth or just single frequency point. Since the computational power today is much more affordable than it was in the past, the choice between the wideband or narrowband information is really a matter of deciding what is important rather than figuring out what we can or what are we capable of doing at all. Today you can easily do both. And in WISP industry, it makes perfect sense to average beam efficiency over the whole bandwidth an antenna is working in because WISPs use their antennas in a wide frequency band. So it absolutely makes sense that an antenna should perform well in the whole bandwidth. And this is why we extended the textbook definition of beam efficiency to a number that is an average of the beam efficiency over the whole useful bandwidth of our antennas and over both polarizations. And this turns the textbook definition of beam efficiency into a sort of super parameter, if you will. It is much more robust and much more reliable measure of side load performance than the single frequency and the single polarization version or for that matter, anything else out there. And vast majority of antennas used for sectorial coverage and with networks are either patch arrays or horns. The patch arrays have many frequency dependent side loads. So their beam efficiency values dwindle around somewhere 60%. Depending on the manufacturing and the design quality. The RF elements horns, now both the symmetrical and asymmetrical have been efficiency between 90 and 95%. So you can actually also see other horns in this graph. And this is to highlight that, you know, as soon as you have to have a heavy horn antenna, it doesn't mean its beam efficiency is high. The stable and zero side load performance are actually not given as soon as you have horn. But we do put a lot of effort into optimizing our antennas so that their beam efficiency is at least 90%. Similarly with the point to point antennas, the directional patch arrays are again at the bottom of the beam efficiency performance due to the many frequency dependent side lobes collecting and transmitting noise, hurting any end and every waste network, really. This is our somewhat better. And generally the bigger the vision antenna is the better the beam efficiency becomes. And that's, again, just if the antenna is carefully designed and well manufactured with any antenna, though, the compromises that you accept at the design stage cannot be compensated by the manufacturing quality since the real world results are at best approaching the design design based results from the simulation. So what is interesting here, though, is the ultra horn. Note that its beam efficiency is 99%. So over the whole bandwidth of operation and both polarizations, the beam efficiency of ultra horn is practically perfect. Only 1% of the signal it radiates is in the side lobes. So if you ever wondered if ultra horn was worth the extra cash compared to a dish with the equivalent game, you have a very clear answer here. With 99% beam efficiency is probably the best performing antenna on the market in terms of noise suppression. The efficiency tells you everything about sidelobe performance. Now, the higher it is, the better an antenna performs. So forget about the front of a ratio or sidelobe level or Etsy masks and focus on the beam efficiency of an antenna when dealing with noise. Not only it is the most complete measure of sidelobes, but it is also extremely robust measure of sidelobes because of all the averaging over the whole frequency range and both polarizations we explained. Since it rarely happens that a wireless link is situated in a completely isolated place, the interference is present almost everywhere. Now, the noisier environment, the more important beam efficiency of an antenna becomes because the higher the beam efficiency, the better the noise isolation. And recently, you can also hear claims of other antenna manufacturers saying, for example, like, well, this patch ray sector works just like horn in terms of avoiding the noise or so on. And to these claims, I would just ask a simple question, what is the average beam efficiency of God antenna? If the beam efficiency is similar of similar values compared to horns, then sure, I would agree, no problem there. But otherwise, if the beam efficiency is anything below 90%, you can be sure that they're not the same. And in the following section, I'll tell you about the practical consequences of using an antenna with high beam efficiency. We can sum up the effect of high beam efficiency antennas into a single statement, high throughput. So in a sector with no other links in the area, you don't mind the sidelobes really. As the number of sectors grows, their sidelobes, though, might cause the noise floor to rise. So the higher noise floor equals to lower throughput. The beam efficiency of patch ray sectors is on the order of 60%. So the remaining 40% of the energy are sidelobes that collect and transmit interference to other links within yours, but also competitors network. So low beam efficiency equals to lower throughput and consequently more unsatisfied customers. Low beam efficiency of dish antennas works in a very similar way. Now the sidelobes collect the noise from its surroundings and transmit it to all neighboring links around it. So whether it's backhauling or a distant narrow sector, the beam efficiency around 45% means it's quite low throughput in high noise areas. Replacing the low beam efficiency patch ray sector by a horn antenna with beam efficiency up to 99%, the noise level in the urban and high density areas is effectively avoided. Now, because high beam efficiency means no sidelobes and no sidelobes means no interference, the final effect is higher throughput and eventually satisfied customers on your end. So addressing the most pressing problem of WISP networks becomes much more straightforward. Only one final advice here really, using antennas with high beam efficiency. High beam efficiency equals high throughput. And the radio manufacturers are of course also trying to help or improve the issue with the noise. The GPS synchronization which ensures that the radios in your network transmit and receive at the same time protects you from self interference, but not from the sidelobes of the competitors antennas. And high beam efficiency ensures you do not have to worry about interference at all. It does not receive it, so you do not need to try to deal with the noise in the first place. So beam efficiency is a very practical antenna parameter. Now, where before the discussion about the sidelobes was limited to many versus little, yes or no, beam efficiency provides a simple numerical measure from 0 to 100%. And it is easy to compare antennas in terms of sidelobe performance. Now, you know that the front of a ratio and sidelobe level are parameters that are not so important, nor very useful in WISP industry because they only consider one sidelobe out of many an antenna might have. On the other hand, beam efficiency includes all the sidelobes, which makes it a very useful metric because it includes all the sidelobes and removes any ambiguity. You can be sure that this metric is reliable. Always ask whether a parameter is a single frequency or wideband definition. In WISP industry, the wideband is simply a must because the spectrum is shared by many. Therefore, wideband performance is vital. And our development's addition to the beam efficiency definition is to average it over both polarizations and the whole antenna bandwidth. You cannot do better than that, really. And therefore, beam efficiency is the ultimate measure to judge antennas in terms of noise suppression in WISP industry. And it is a tool in your hands for that matter to make better decisions for your business. So please use it and ask for it if an antenna you're looking for doesn't have the beam efficiency value in its data sheet, just go out there and talk to the manufacturers and ask about it. And to make it easy for users of our products, we added the beam efficiency of our antennas into all their data sheets. So we are a transparent manufacturer and want to provide our customers the information that is important and useful. Okay. So that was about beam efficiency. And now let's just go through few most common things that we get asked over and over again. Where to buy our products, for example, is first of those questions. And on our web page, rafferlament.com, the stock locator tells you everything you need to know. Just one click away. One click divides you from finding out where you can buy our antennas. Another very frequent question is how far your antennas go. WISPs may be sometimes worried about the lower gain of horns compared to the traditional patch erase sectors, but the amount of noise they suppress, the amount in dB is actually outperforming those one or two decibels in gain that they're missing compared to the patch erase. And nevertheless, to get an answer to that question of how far our antennas go, I recommend you using our link calculator. It is a free tool on our web page, again, rafferlament.com. And on the right side, you see the tab, which is now circled in green. That brings you to the calculator. And there you can enter. You can choose any of our antennas, set the parameters of the access point radio, set the parameters of the client device. And you will get a very good estimate on how far our antennas can go and how well they can perform. Because in this image, you can see there is the colorful coverage pattern is actually showing you what the MCS levels are supposed to be with a given setup. So it doesn't only show you the signal strength. But actually, it goes one step further because it includes the parameters of the client device. And the result of that is the MCS level coverage, which is directly tied to the maximum throughput that you can expect with the given CPE. We get also often asked, like, how do I become a distributor of your antennas, of your products? So again, the same starting point on our webpage, you slide all the way down and click the Become a Distributor link, which will bring you to this questionnaire, which you just see and where you fill a bunch of information about your company, about yourself and your plans for the future and so on. And once you click Submit, we will contact you very soon. We also have RFELab.com, which is an online discussion forum. It's a traditional discussion forum, as you probably mostly know. And I encourage you to actually register there. There is a lot of useful information about our products and it's the fastest way to get your questions about our products answered. Or you can provide your feedback. If you don't like something, is there something you're missing? Or if you just want to share your experience with our products. And we also announced upcoming webinars there and also put recordings of the webinars, such as this one. And actually, we're also present on Facebook. So I invite you to join the RF elements English. It's a discussion group, which serves similar purpose. So at RF elements, we, as I said, we really try to do what's best for the customer and the industry at the same time. So through our noise rejecting technology combined with the near zero loss to a sport ecosystem, the wide toolset of 10 different horn antennas with different beam widths and different gains. And exceptional noise rejection capability really enables massive scalability of wireless networks, simply because you can keep adding more and more sectors without having to worry about those already in place. And because of that exceptional noise rejection, they will not interfere and they'll get the most out of all your radio devices as possible. On our YouTube channel, we have a playlist called with traveler, and I encourage you to check that one out. It's a series of short interview videos with with risks from all around the world, people like yourself, and we interviewed about what is their experience with our antennas. We also have a playlist called inside wireless on our YouTube channel and that one features very short snippets of three minute videos, approximately about all kinds of concepts from the world of RF engineering. So if you're an experienced with, you know, RF engineer or just starting out your with business. Make sure to check them out and share them with your colleagues. They might be useful, you either refresh or maybe even learn something new. Check them out. And this concludes my presentation for today. I wish you a nice rest of your day and looking forward to meet you in any upcoming webinars. Bye bye.