 So good morning. My name is Tomasz Wolenski and I'm a product and marketing manager at RF elements and today we'll talk about sector antennas and Particular about horn antennas Because there's so much to talk about considering the topic of antennas. We Divided this webinar into two parts to both horns and patch arrays are topics big enough that they deserve their own time slot to Give a good overview of each technology And in this webinar, we'll we'll talk about horns and there will be another one in June So that's a heads up for you about those patch arrays So if you're interested in all the whys and halves of the patch arrays make sure you you don't miss it So what makes an antenna a great sector antenna? So most wisps know about game being with front-to-back ratio, maybe a few more And on top of that, you might already know that there are many parameters antennas have and here you see a List of the most important sector antenna properties from our RF elements point of view for Wisp networks Now ideally every deployment you do would get a custom treatment Yeah, meaning you would look at all the nitty-gritty details of the variables You are working with and and playing your deployment accordingly but of course we understand that wisps are extremely busy during their working days and And working nights often too And there might not always be the space to give a proper care to each link, of course so Depending on your experience, maybe you might already know as well immediately what hardware you need to deploy and how So you don't really need to plan anything What we show here is a rather exhausting list as a reference if you have the space to plan optimally Now whether you stick to it or not, of course, it's you know, what I like to call it the art of what's possible But it's good to remember that you can always come back to this presentation because we'll put it on our YouTube channel At some point after after the webinar is over during this week So if you subscribe to our YouTube channel, you will get the notification when we publish the recording Now because horns are based on a waveguide technology and patch rays on a printed circuit board technology There are fundamental differences between them Although both types of antennas are used for the same job, the physics of their operation differ vastly Which results into different factors influencing the side-loop level stability of the radiation pattern or co-location capabilities Now wisps are increasingly sobering from the approach of quote-a-quote cheaper is better in terms of the hardware they choose to deploy Now although in the past there has not been much choice in terms of the hardware Nowadays wisps have the experience to know that besides the price the network scalability stability the balance of the horizontal vertical chains or Coverage stability are really the key elements to running a successful business and we're here And are aware that it's a lot to digest actually, which is Also why we are doing this webinar for you So as advertised This webinar will be about horns and we will look at them From the angle of a wisp a wireless internet service provider That is through the filter of conditions that wisps are dealing with in the unlicensed 5 gigahertz bands And again, this is a very specific lens through which we we are actually looking at this antenna technology And this lens would be different in other industries or frequency bands But to make this webinar as relevant as possible to you We focus on the 5 gigahertz unlicensed band wisps are relying on a lot So horn antennas come in various shapes and sizes and they look and function very differently compared to the patch erase And even though horns have been around since the end of the 19th century They are finding their way into the wisp industry for for less than a decade really So how does a horn antenna work? Every horn antenna Starts with a waveguide and like coaxial cable the waveguide is a type of transmission line or cable if you will Which is used to to transfer the high frequency the RF signal from point A to point B Now in this example, we are showing a circular waveguide, which is essentially a hollow metal pipe through which the RF signal travels Now the advantage of waveguide is near zero loss and the capability to handle very high power signals Now while the coaxial cable works from zero frequency, this is not true For for the waveguide because of the lack of the center conductor and the physics that are connected to it So if a waveguide doesn't work from zero frequency from DC, what is the frequency where it starts working? Let's call this starting frequency a cut-off frequency and below this frequency no signal can travel through and Whatever is brought to the To the waveguide it will be simply reflected back to the radio above the cut-off frequency The signal can travel freely so effectively waveguide Functions as a high-pass filter below the cut-off frequency Nothing goes through and above it the signal travels freely and all this is basically due to the physics of the waveguide operation The cut-off frequency depends on the waveguide dimensions now in the case of the circular waveguide It depends on its diameter as with most of the things in the world of RF engineering the physical size of hardware is inversely proportional to its operating frequency Now in the case of the cut-off frequency the bigger the waveguide diameter is the smaller the cut-off frequency and vice versa the smaller the waveguide diameter the larger the cut-off frequency is at cut-off frequency Which we call FC and the signal starts to travel in the waveguide and it feels and its fields Only have one mode and by mode I mean the pattern of the electromagnetic fields you can see on the animation as the colorful image So the color coding tensile tells us how how strong the field intensity is The red in this case is the strongest and the blue is the weakest and the rest of the colors for for anything in between Now let's this let's call this mode M1 The M1 mode is is well understood by the physicists and engineers Or any since many years and because of that we know how the waveguide behaves when it's operated in This first mode So devices based on the waveguide operating in the M1 mode are also reliable and well understood As we keep increasing the frequency beyond the first cut-off Yeah, the FC when we cross the FC to yeah, which is another cut-off Another mode starts to exist and combines with the first one and creates the patterns you you see display And then at FC 3 yet another mode starts to exist in the waveguide And again combines with the previous two creating the result of the field pattern You can see on the display and so on and so on This is this really going forever. It is really no end to the number of possible modes on the waveguide and we call these additional modes higher order modes and The total energy of the RF signal that travels through the waveguide is Distributed among all these modes so we can say that the higher order modes Sort of suck the energy from the first mode Yeah, so since we usually pick up and work only with the first mode So in in that sense the the higher order modes are actually not useful or desirable Since the higher order modes Change the radiation pattern of a horn antenna that is based on it on on such waveguide operated with With more than just one one more This change of the radiation pattern is undesired Which is why It also it also actually not only changes the the radiation pattern But also also the you know the whole operation of the antenna becomes hard to predict and because of that We restrict the bandwidth of operation of a typical horn antenna between the FC and FC 2 Into a so-called single mode bandwidth and in this bandwidth We are sure that only the first mode exists which makes the Radiation pattern of a horn antenna Stable and lets us radiate maximum power of the RF wave, you know, which is what we what we want and this single mode bandwidth is Is a typical limit or you know the rule of thumb Yeah, that the signal mode bandwidth is what limits the bandwidth of in which the horn antennas can operate Or are typically operated You can look at Horn antenna as a transition between the free space and a waveguide It transforms the guided wave inside the waveguide into a free space wave, which is traveling through the air Now horn is an aperture antenna. So this means its Properties are determined by the shape and the size of the aperture and in this in the case of Of a horn also by its length So two main properties determine the gain of a horn antenna the size and the shape of the aperture and the length of its body And if the aperture of the horn is symmetrical meaning It's a it's a circle when you look from from the front The radiation pattern of a horn will be symmetrical as well when looking from the front, of course If the aperture is oval or any other Irregular shape the radiation pattern will be asymmetrical or otherwise change So the main beam will be will be wide in azimuth an arrow in the elevation plane or vice versa depending on You know on which side the the aperture is squished either from the sides or from the top and over the years The engineers have come up with graphs such as this one to speed up the design process of horn antennas Now there are three curves which are partially overlapping. Yeah, the red colored ones So this curse tell us how the gain of a horn antenna changes with changing the aperture Diameter so on the x-axis you have the aperture diameter and in the y-axis you have the gain corresponding to to that and The difference between these curves is in the corresponding aperture length and so the lowest curve corresponds to l equal half of the wavelength to to l the length of the body equal the six times of the length wavelength size and In the middle up to the 50 times the wavelength size to the top right corner curve So the design process of a horn starts with the choice of the body length l then the designer looks at the graphs finds the The D. Yeah, the diameter depending on the game. He wants to achieve And there is also a black dashed line as you can see and that line tells us what D Needs to be yeah, or what the diameter of the aperture needs to be to achieve the maximum possible gain of a horn Given that it's wave the length of the body is fixed. So this is where Why there is a sort of knee yeah on each of of these red curves The top of the knee marks so-called optimum horn Which means that for a given length of the body l this is the maximum gain you can achieve And here are a few examples of various shapes of horns some are rectangular Some are flat on the horizontal or vertical side Some have you know strange structures inside and so on and each of these variations Of horn has its advantages some are white band some are easier to manufacture and some have minimum side loads So depending on the application each of these horns has its use case Let's first have a look at the strengths of horn antennas and which we'll start with the side lobes The key benefit of a horn antenna is the radiation pattern with no side lobes Now there is no diffracted or parasitic radiation as with the patch arrays Because of the RF wave is fully confined within the wave guy and the radiation of the fields is a lot more controlled and gradual thanks to the progressive widening of the horn mouth and The result of these horn properties is a clean main beam with no energy wasted in unwanted directions and No noise collected from unwanted directions as well Some of you might already use our antennas. So I'm sure you already heard that Our antennas don't have any side lobes But is there a way to quantify the side lobes? Yeah, is there a numerical value variable that describes the amount of side lobes an antenna has or doesn't have? Well, indeed. There is and it's called beam efficiency Beam efficiency is the ratio of the energy contained in a main lobe to the total energy an antenna radiates In other words, it tells us what part of the radiated energy is going into the main lobe Now the higher the beam efficiency is the more energy is in the main lobe, which is what we want where on the other hand Less goes everywhere else meaning into the side lobes. So beam efficiency Quantifies the side lobes it gives us a numerical value that clearly says how many side lobes an antenna has So comparing antennas in terms of the side lobe performance is extremely easy The higher the beam efficiency of an antenna the less side lobes it has and it can have values from zero to hundred percent Yeah, where a hundred percent is the best meaning that the antenna has zero side lobes and the zero percent beam efficiency means That well an antenna is one huge side lobe And here we're looking at your radiation pattern of a traditional sector. So if it's beam efficiency is 58 percent The 58 percent means that the power the antenna radiates Goes into the main lobe those 58 percent. Yeah, there's the remaining 42 percent Therefore must be in the side lobes and note that all the side lobes are highlighted So beam efficiency includes all the side lobes of an antenna Not just one or a slice of the radiation pattern But the whole package and the complete set of the data the full 3d data unlike the Front-to-back ratio side lobe levels our Etsy masks, which are practically useless parameters as a measure of side lobes and Wisps use a quite wide part of of the unlicensed spectra But in the antenna textbooks the beam efficiency is defined at a single frequency for a single polarization And this is the case actually for most textbook parameters And again, it really is up to the user and mainly the manufacturer to consider whether one should care about the whole bandwidth or Or just a single frequency point and since the computational power is much more affordable Now days than it was in the past the choice between the white band or narrow band information is really a matter of deciding What is important rather than figuring out what can be done? So today you can do easily both and responsible when there's should definitely, you know think twice which What parameters do make sense to consider white band or not and in with industry? It makes perfect sense to average beam efficiency over the whole bandwidth an antenna is working in simply because Wisps use their antennas in a wide frequency band So it only makes sense that antenna should work and perform well in the whole bandwidth and therefore we extended 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 and This by doing that we turn the textbook definition of beam efficiency into a sort of a super parameter It's much more robust and more reliable. It has much bigger information of value It is a more reliable measure of sideload performance than the single frequency and single polarization version so or in fact Compared to anything else out there and vast majority of antennas Use for sectorial coverage and with networks are either patch erase or horns And the patch erase have many frequency dependent side lows So their beam efficiency values are rather low around 60 percent depending on the manufacturing and design quality it can vary and Horns generally have much better beam efficiency, but be careful here as well You can see there are other horns in this graph We're showing you right now as well and this is to highlight that it is not a given That when you have a horn antenna, it automatically means it has high beam efficiency To achieve the stable and zero sideload performance really takes a lot of effort even with horns So beam efficiency tells you everything about sideload performance while front of a ratio for example or other Parameters you might be knowing almost nothing really Comparing to front of a comparing front of a ratio As used in the WESB industry to beam efficiency It's like looking at the world through a keyhole in the case of front of a ratio and being on top of a hill seeing a wide Open space when you see everything crystal clear in the case of beam efficiency. The difference is simply vast So let's go now to the second strength of Horn antenna technology and that's the flexibility of the of the design So horn technology has the flexibility that is needed to provide the beams Fitting various coverage scenarios and as we saw before yet by adjusting the dimensions and the shape of the horn You can achieve the desired performance regardless if you if you need a narrow or a wide sector antenna and this is very powerful feature of Horn technology giving you the ability to adapt to really any conditions you might encounter while The planning and deploying your network coverage Horn technology is so flexible that you can actually choose if you want to change the beam width in both Horizontal and vertical planes or only one of them Yeah, so when you squeeze the horn only from you know from from the sides Yeah from the left and right which Yeah, in this case is the horizontal plane you you change the beam with only in the elevation and This is a little bit counterintuitive. Yeah, like squeezing the horn on the sides The radiation pattern gets squeezed from the top and bottom. Yeah, so that's one of the Counterintuitive things with horns, but know that it it works this way And this results into an asymmetrical beam now which fits particular scenarios with rather flat landscapes and Adds a few decibels of gain so you can cover more distant areas And the result of all these possibilities is a wide tool set of horn sectors that you can have which are Suitable for different scenarios. Yeah So the top row shows all symmetrical horns and that's symmetrical horn sectors with the gain ranging from 10 to 18 and a half dbi and a large span of beam widths from 30 to 90 degrees and the second row shows you the asymmetrical horns with the gain between 16 and 20 and half dbi and For example, the 90 degree asymmetrical horn has 16 dbi gain. Where is the symmetrical one? Has 9.6 dbi gain. So here you can really see the power of Shaping the aperture. Yeah, just by changing the structure the shape of the aperture In this case, it's quite intuitive. Yes, quizzing the horn designed on the side on one side you will get more gain out of it, yeah, and In the same row is an example of a 24 dbi gain horn We call the ultra horn for point-to-point or narrow sector applications So frequency stability, this is important for customer service quality stable Properties over there over the whole frequency band Means that also your service can basically Be very stable meaning that your customers will Experience a really high quality quality quality service provided by you as a waste and actually if You know from the point of view of human psychology As people we really enjoy the stability Rather than you know having seen say those 300 megabits per second throughput at I don't know Few few minutes a day. Yeah, so the stability is something that is way more important Not to say that the maximum throughput actually depends on the radio More than the antenna what but of course the antenna is also part of it and ideally will be very stable So here you see how the gain of An example of the asymmetrical horn with the 60 degrees beam with changes Yeah, so over the whole bandwidth the changer of the gain is really minimal and this is no, okay Let's say ideally the the red curve would be completely flat and horizontal and What you see is is quite near to it. Yeah, so this is actually really good Meaning that when you when you switch the channels You will not see you will see a minimum change in the received signal strength The coverage pattern should be also stable and not only the maximum gain and here you can see how the gain changes Changes with frequency In the whole on the whole radiation pattern Yes, so you can see that the radiation pattern is changing somewhat But the resulting change of the coverage you can see on the right is actually really minimal when we when we use horns and Here you see how the coverage changes, it's a little bit different different Representation but this one is actually all very close to what the reality is So here we show the example of a 60 degrees symmetrical horn and you can see the frequency changing And also the resulting change of the coverage pattern. Yeah, and this is really a result of a simulation Yeah, so we took the radiation pattern of this antenna and propagated on that surface Yeah, so it's really the closest thing to reality. You can see and besides that Little growth at the beginning of the spectrum. You can see that it's it's really stable Yeah, so that which is really something that you want and the coverage you can rely on and Similarly with the asymmetrical horns. Yeah, here we show an example of the 60 degree asymmetrical horn and because of that asymmetry The the fluctuation of the coverage is a little bit a little bit bigger, but overall it's it's Extremely stable when we compare it to the patch erase sectors or any other sectors you might be using For your for your coverage in your Wisp networks Another component of the coverage stability is the balance between the horizontal and vertical antenna systems So asymmetrical horns have the same radiation pattern for both polarizations, which perfectly fits this criterion So you don't have to worry about the customers on the edges of the sector And in comparison the competitive patch erase sectors have unbalanced horizontal and vertical chains Which has negative influences on their field performance, especially of course when you're switching between the polarizations So far we have shown the properties of a horn antenna Which is designed to fit all the criteria we talked about as good as much as possible Yeah, but do not get fooled like really not all the horns are performing this way. There are many types of horns and even when a given horn Has certain advantage it takes considerable effort to optimize the antenna so that it has the properties We are looking for and here you can see the radiation pattern of RF elements 90 degree asymmetrical horn No side lobes only a clean main lobe in both elevation and as in with planes Hortical the horizontal and vertical patterns are are nearly identical, which So there is barely any difference between the red and the blue curves as you can see And this is an example of a so-called pyramidal horn meaning that it has this rectangular Cross-section and shape an inherent property of pyramidal horn is that it has side lobes Despite that in this example it has two wings on on each side You can you can see which are intended to suppress this side lobes nevertheless this type of a horn Definitely has substantial side lobes another problem of this antenna is the mismatch of the horizontal and vertical Polarization patterns which results into different background noise conditions due to the side lobes when switching between the polarizations and eventually mismatch of performance Even with even the width of the main beam is different for each polarizations as you can see from the plots Here is another example of a 60 degree asymmetrical horn with with similar pop problem of the side lobes again The side lobes are there and they're substantial as well as the mismatch between the polarizations Causing the problems. We we already mentioned so the null coverage a Fair different from traditional sectors and this this kind of Is a is a source of confusion here and there between the users So with a horn you can easily cover the null areas near the site, which is really not possible With the traditional patch erase sectors and of course you can tilt the patch erase sector Yeah, so that it actually covers the now zone as well But in that case you will completely lose the coverage of the distant areas the horn Instead illuminates the whole surface you pointed at all this. Thanks to that symmetrical radiation pattern and its symmetrical shape Which really is a great advantage for a sector antenna In general the radiation pattern of a horn with more width in the elevation Allows for much better coverage of the null areas near the site Which is again almost impossible to achieve with the patch erase the zero side lobe radiation pattern is especially useful in The sparsely populated areas outside big cities now the scalability of the whole combo or Toolset of the symmetrical and asymmetrical horns gives you the flexibility when planning out the coverage when you need more gain and Have customers closer to each other Take the narrow over beam horn when the customers are more sparse and not so far away from the side Then a wide beam with will will come more handy and So connected to the shape of the radiation pattern in this case the asymmetrical horns Yeah, it's again it's sort of like halfway between the symmetrical horn and And the patch array antenna in terms of the shape of the main beam so in that sense it also the Scenarios into which This antenna is suitable kind of fall in between. Yeah, so The asymmetrical horns are really the best In the mildly hilly to flat landscapes. Yeah, they would probably I Perform the best when When the landscapes are not very rugged On the other hand the symmetrical horns have radiation pattern With that extra beam with in the elevation plane and that will allow you to easily cover those deep Valleys now which are impossible to cover with any other antenna or let's say with an antenna And that has narrow beam in the elevation plane Yeah, those extra degrees will simply Let you cover the valleys Like no other antenna. It's simply very easy the variable beam with and the gain of horns Really enables great scalability of network as such With asymmetrical horns, you have more tools to plan your network in a in a sustainable way Due to the lack of the side loads meaning that growing the number of your areas covered the of your customers connected will will not degrade as Will not degrade the functioning of the network already deployed so if you have sectors and you know, we want to keep adding more and more customers the horn technology will enable that simply because of Not collecting and transmitting any noise So let's go to the To the things about horns that are That are not so good. Yeah, and one of them is the cost of manufacturing So traditionally the manufacturing of a horn antenna is a custom job Which means it's an expensive job and these antennas are Full metal. Yeah, there are solid metal body structures sensitive on the dimension accuracy So to achieve high quality product Yeah, it is not uncommon to to use expensive milling machines with tools as you can, you know see illustrated in the in the image here and This is valid for high or low frequency horns without exception Nevertheless at our fellow men's we we put a considerable effort and energy into into tweaking the design or to optimizing the design of our antennas Resulting into into reasonable manufacturing processes to a degree that these antennas can be mass produced while Maintaining the quality and the performance standard at the same time So in the end it is possible to make a horn antenna out of long-lasting high-quality non-corrosive materials and Without any compromises on the quality of our performance, but of course it has to be done, right? another Potential downside of the horns is the limit To the gain that can be achieved with these antennas so comparing the Point-to-point horn with a point-to-point patch array with similar gain the difference of The cross-section is around 30 centimeters, which might not seem like much at at the first glance, you know, but To get a patch array antenna with six six more DPI gain Yeah, the area of the printed circuit board will increase approximately five fold Right whereas when scaling a horn on the other hand Yeah, you you have to understand that is not the only the area that has to be increased But actually the whole volume of the antenna that has to increase as well and For comparison to get a horn from 18 to 24 Dbi Its volume will have to increase 15 times and that's a lot which puts a whole You know a lot more pressure on the designers to develop the manufacturing processes that Will accommodate antenna of such size while at the same time maintaining a reasonable cost of their production so and here we have a Summary of the properties we just talked about So the present state of The industry is that for a majority of whips These parameters are really important and horns Definitely hit the nail on the head in terms of the zero sideload performance. Yeah, because of the physics of this antenna technology The horns really Do not have any side lobes Or in other words have very high beam efficiency at the same time They also are very stable with the frequency as you change the channels The performance of the horns does not change and their frequent their performance is actually stable over a very wide band and Also the balance between the horizontal and vertical antenna chains is yet another bit Yeah, that you know kind of adds to the other positive properties of horns In terms of the unlicensed waste networks But of course as everything else also horn antenna technology has its downsides And one of them is that the gain you can achieve with these antennas is actually limited And it's moderate compared to the patch race and compared to what you might be used to But here again, you know, you trade the few DB's of gain for many decibels Improvement in the SNR. Yeah, thanks to the zero sideload radiation pattern, which is actually in the end adds up as improved service and improved quality of the connection you provide to your customers and The horns traditionally while being expensive to build You know when developing Manufacturing process it's possible to you know to optimize it to a degree that enables that mass production at a reasonable price which Which we which we have achieved at RF elements, but of course The process becomes quite complex Nevertheless in the end it's possible so eventually I would just like to conclude that the at RF elements we Provide you a set of tools for optimal noise rejection Here our twistboard ecosystem Enables zero loss transmission from of the RF signal from radio to the antenna and Combined all together this antenna toolset enables massive scalability And that is really unseen and unheard of before we Introduced the horn antenna technology into Wisp industry meaning that you can really grow your network in a sustainable way Yeah, and you don't have to worry about every new added sector and Wonder if if your whole network will will come down with with that You know added noise that it might bring no horns do not do anything of that. They really let you grow sustainably I'd also like to invite you to check our YouTube channel where we have with traveler playlist where Wisps like yourselves You know talk about how our antennas have Improved or or help them solve their problems So we have customers all over the world and wherever you're from The the horns you probably find the horns there already so if you want to hear how your colleagues Benefit it from using horns if you're still on the fence whether you should give it a try or not Please check those videos We also have inside wireless playlist on our YouTube channel and this is a series of short educational videos about all kinds of Concepts from the world of RF engineering. So whether you're a experienced Wisp an RF with veteran or or maybe you're just starting with your wisp. It doesn't matter These short snippets are are very useful for either refreshing or learn something new We also have RFELab.com which is our Discussion forum where when you register You you can you know find a huge resource in this forum for information about our antenna technology And you can of course ask your questions if you have some Or simply search through those which have been already already asked before and we also announce our Attendance on difference different industry events. Hopefully now with the pandemic situation calming down We'll be soon able to have in-person meeting and I hope to hope to see you on some of those events