 Okay So Hello and welcome. My name is Miroslav My base station is ST micro alternates and I'm a member of RF team focusing on WB and WBA products. So Bluetooth low energy microcontrollers This presentation is purely RF. We will discuss Radio module topics mainly focused on antenna part So anyone interested Stay here for a while Nothing we will deal with the radio modules. They are popular today and Their portfolio is constantly growing today We will touch their advantages and disadvantages as well. You can get a better Picture if this is a beneficial for you or not Radio module is a complete solution that integrates all the parts you need for wireless communication Simply packed into a small Device And it is easily assembled to your board and you don't know you don't care about Hardware internal structure even the stick is ready to use Is it already certified? So it is the fastest way to get the device to the market But it could have also some usage constraints Let's say on the RF performance is a Limited if wrongly applied The reason for impacting our performance Is mainly the antenna the antenna must fit into a small space in the module It can suffer from its small size now we will deal with our parameters and performance of embedded antenna while the application of the module Differs from the recommended conditions All results will be demonstrated on 3d simulation model of the module Fit it on a reference board So let's talk about advantages the certification process is short in time and Less cost than for discrete solution One of the demands is the proper implementation of radio Or radio module according to the installation guide of the manufacturer One of the demands is the let's say Yeah, the module is press certified. It means that Not only reducing the cost And time for certification by the development time as well You may avoid several rounds due to design mistakes that could be done with a discrete solution Testing a radio module with embedded antenna Isn't easy as there is often no way To conduct it connect to RF output All measurements on RF must be done in radiated mode However, a ready-to-use solution doesn't require many RF measurements a discreet solution request much more effort measurements knowledge and equipment and many customers who just want to acquire connectivity to To the device Do not even need this equipment Then a radio module must have a shielding Yeah, this is the FCC requirement and a discrete solution Is a let's say There is a need for RF external components There's no need for RF external components and to deal with the settings all is in Therefore a radio module is a fastest way to get the device to the market And the disadvantages the radio module is great to be used for undemanding conditions not impacted Sorry, not impacting embedded antenna for specific conditions This solution may not be usable or some lover performance should be expected To keep certification the bomb and layout of module cannot be changed In other words, it cannot be adjusted for external conditions No modifications are allowed on the antenna side For a high volumes This can be costly solution and it must be balanced between cost time of development phase certification process and Yeah, etc. Okay Several facts about the radio module as it consists of an antenna a radio module request appropriate Implementation the antenna is a sensitive component No matter if it's outside or inside the module If possible follow a manufacturer Recommendations from the application node You will get closer to the optimal Solution and avoid the problems that I will outline here The application node shows an optimal placement or set of possible placements a difference Among the options lays in our performance while less recommended options are worse, but still usable so If the antenna is designed for corner placement Use the corner of your PCB if the module incorporates the antenna designed for Center edge placement. It is best to keep this location We may also get some further information such as size of the PCB or some warning About the influence of the metal and human body, but the background How to deal with this information is often not given so Even if you have no experience with a radio module, you should understand the basic Ideas and the basic recommendation and our are clear almost all modules integrates Integrate the antenna that needs clearance Below the antenna it is a free of metal area and this clearance must be preserved as We will see later You should consider the size of the PCB often it is a reference or Evolution board to which the antenna is adjusted Maybe it is a surprise for you about the shape and the size of PCB Has certain effect on radio performance. It is especially about radiation efficiency return loss Resonance frequency shift and change of radiation pattern For a certain type of antenna The PCB represents a ground plane needed for antenna operation metal objects Should be away from the module. We would like or Yeah, we would like to avoid any change of antenna structures impact to antenna impedance and Far field change, but it depends on size position Sorry on the size of the PCB position of the PCB and The distance from the metal objects from the antenna We met with various plastic housings we will see some results with it on further slides a Very unpleasant case is proximity of human body. I will show some results on On this on this case What would happen if antenna will be very close to human body and It is a quite often case This little guide could help you To find out what is the main contributor to low performance of your radio and what To do when you are facing such issues. Yeah, so the first case Is size of motherboard All information given here is based on full 3d electromagnetic simulation and It is related to exactly this case It cannot be applied to else configuration. Although the general principles are preserved Yeah, so All these results are based on the model of the module operating in 2.4 gigahertz band assembled on reference board It is the case The second case from the left side The other boards preserves the module and Particle change is depicted this case considers change of motherboard size and These were extended by size denominated in friction of wavelength And Report change in two directions. So in X and Y axis Size of the board influences the parameters of Antina and thus our performance of the module. I suppose you may know the terms like radiation efficiency and Maximum gain of antenna losses are in the electric and Conductive materials of antenna and in parasitics of the matching components and To what we observed a change of radiation pattern is one which Expresses an amount of delivered power from the antenna into a particular direction reference board is close to an omnidirectional case or Omnidirectional pattern as you want. So if the depicted radiation patterns becomes more yellow or green In some parts the direction suffers With with the power so it losing the power in that direction There is a resonance frequency variation up to 65 megahertz ready-to-efficiency Was almost no change This parameter But we noted variation of maximal gain of embedded antenna in 3db range and Omnidirectional pattern transforms into highly directional one or fragmented one Okay, so moreover larger PCBs Reports higher gain, but this is only in Particular direction the others are suffering of of lack of lack of the game and Their conclusion the antenna maintains impedance matching in the band and preserves radiation radiation efficiency and The far field become more directional Yeah, let's look at the next case. It is a case Or change of ground plane Only in X axis We can observe here Not so huge change of radiation pattern. So we would Expect still the same amount of delivered power in all directions But there is a gain as well which contributes on a delivered power The radiation efficiency is also changing That means that the radiator That means that the radiated and accepted power ratio differs It can be a matter of antenna impedance as a conductive as conductive and Deltic losses should be almost the same The basic facts about this case a resonance frequency Various up to 50 megahertz radiated efficiency is quite stable, but with stronger variation When compared with the previous case a Surprising feature is that the small the small board Acquired better efficiency Which makes me happy as this case is a very often case for for customer Maximum gain of embedded antenna is in 2db range and Omni-directional pattern as you can see here isn't present, but The change is negligible. We can also See it on the other side far side slide Antenna for the largest plane Here doesn't reach higher gain what we observed here Or in a for a previous case for both sides extensions But it keeps radiation efficiency and gain and the far field is almost omni-direction For me it can be one of the possible ways Where the larger board is needed and a small conclusion the antenna maintenance impedance matching in band with acceptable resonance frequency change and Size of board has only a small impact to radiation efficiency and antenna preserves Similar far field a different situation is for the Following cases the PCB extension is made in y-axis The radiation efficiency is heavily impacted It varies around the lower values the same can be said for Maximum gain however it gets more Gain for the largest boards What should not be overlooked in this In this change The far field the far field shape yeah far field shape it gets more directional character and becomes more fragmented Resulting in steepie change in LSSI value while moving Over or across the pattern cut The smallest PCB has bad numbers It is due to the not preserved so-called counter poise Or for antenna which is critical size for PCB where antenna is able to operate Let's summarize Resonance frequency variation Up to 75 megahertz seems to be quite too much Smallest board reach very low radiated efficiency on contrary of large boards that have enough radiation efficiency The maximum gain of embedded antenna is varied in 4dB Range and far field becomes more fragmented as we can see here With extension Dimensions and this is what I told you a while before Fragmented far field is quite small With quite small Efficiency and increasing maximal gain due to changing directionality. I would point out the interesting matter The maximal gain is aiming toward the opposite side from the radio module if this could someone confuse and When when implementing and long long PCBs The extended board in the y-axis maintains impedance In bent while possible worse numbers in dedicated bent corners Floating radiation efficiency and maximal gain are depending on size Small size board has not enough counter poise while With low efficiency Large boards have highly fragmented far field Okay, next I Need to skip some some slides. I need to be more quick So I maybe Present this The usual case is placing a module to another location on a PCB Data sheets often claims that this is okay So supposing no impact But we can say that it isn't so much truth. The first case is placement along the shorter side of the PCB the single case Single cases we called as a corner or center edge location it should be selected based on the Antina Type integrated in the module it is visible that reference board Is likely selected not optimally reporting less efficiency and gain Although the written loss isn't visible here far field is turning for all investigated cases and far field is getting unfold Radiation efficiency is quite flat Bottom right You can see a graph for possible range To see a difference between the cases it is all it is Calculated based on freeze equation for fixed output power 5 dBm and reference received power minus 70 dBm Next slide. Yeah fathers This is About a placement along The longer side of the motherboard we can claim similar things For these variants, but the dependency is much more visible a reference board size is always preserved, but the position of the module is turned by 90 degrees a Small surprise the module reports better efficiency maximal gain the n-range when module is on the top With the worst result is for a bottom position written loss and The resonance frequency are quite stable Far field is turning around and Radiation efficiency is changing a lot. We can see that the maximal gain has different Efficiency Different value three maximum gain has different values and the bottom right is a Again the graph for a range that reports significant Difference between simulated cases and the short conclusions to this case best to keep an Original location on the module position at the same time if needed to place Place it else use the shorter edge Resonance frequency is kept inside the band and the lowest performance is for bottom left side I must skip the story for this Maybe one case I will comment We simulated cases with metal object nearby the antenna In sizes selected in again infraction of a wavelength the metal sheet is positioned parallel in this case to the main board and results Resonance frequency is almost kept the same smaller sheet becomes a part of the antenna impacting and the antenna impedance and the all parameters are getting worse Larger sheet behave as a reflector So it makes the antenna very directional so it concerns electromagnetic field and The antenna reports high gain and efficiency What's only in one direction? so unfortunately Then this arrangement lost a many directional pattern. I would point out a range calculation Here is a huge improvement for directional cases Must keep some other cases that are consents to different position of the reference board with the module to the to the sheet but Yes, you can see very simple case Case is this one to the to the previous one and this is Let's say not impacting so much I Would like to show you not plastic This case it is a plastic housing and human body Now we will investigate what happened if the module would Be exposed to human body. You probably know It has a huge impact so variables or handle hand held devices should be adjusted for these aspects okay, so the goal is human body touching the plastic housing and Everything is impacted Resonance frequencies out of the desired band Radiation efficiency is decreased a lot at as same as maximal gain Far field shape is lost the on the directional pattern is lost and What concerns to maximal range? It has decreased a lot only in Only the XZ XZ Plane position is a bit is a bit better But you should remember that It is not able propagate through the human body at all Remember a human body Significantly detunes the antenna mostly when aligned to a direction of propagation and linked with a Impact to efficiency and gain Radiation pattern shape Significantly depends on position If the device is handheld or variable Try to Try to create enough spacing If it is not possible to have a spacing and Tina will suffer from human body presence You must count with losses or Use a custom design antenna or even discrete solution Yeah, I three minutes So We are at the end and I guess a little reminder of what we have learned today When searching for the fastest way to get connected Using the radio module is your way when facing some issues as discussed here like metal objects human body You should avoid them or at least mitigate an impact if you are not confident about No issue of this kind Just use it Some recommendation at the end if you are interested in modules The basic is to carefully read a documentation and application note There is useful information given based on what you have You have learned you should be able to Assess possible thoughts in applying the module if you have any doubts About your implementation do not hesitate to ask we are for you Here and we will be glad to consult your design if you would if you would like We may give you a priceless advice for free Okay, so and that's all for today. I have no time. I hope you enjoy the presentation and if you have any question or comments, we can take it here or Discuss them later on ST micro electronics booth at the whole in hall for a So, thank you