Teardown of Kathrein 1800/900 MHz Antenna For Mobile Phone Base Station

[@MrCripplerking]

At 11:00, it's not exactly a combiner - it is a diplexer (basically a splitter/combiner that converts one input into two outputs that are split across two frequency bands). It uses distributed element transmission lines to avoid discrete components. What you see on the trace is basically a combiner and a set of filters in one package. The "plastic" you took off the top to expose the traces is probably the same material as the board itself, and is used to realize the transmission line as a stripline within the diplexer body cavity. The diplexer lets the antenna have a single input/output port that can be used for multiple different bands.

[@sagit0007]

Yeah, it's a common mistake.

[@KaizerPowerElectronicsDk]

I have done it as well with duplexer and diplexer :)

[@jsc3417]

Where do you even begin to design something like that

[@klausnonn6357]

Hi , what do S11 S22 and S33 should look like ...? Thankz

[@rezap1356]

he is not wrong though. That piece "combines" for uplink (signals received by 2 antennas on 2 bands get combined into same wire) and it "splits" for downlink (900 and 1800MHz signals from the base station come in the same wire, then get split for transmission through two separate antennas). Actually, every combiner is also a splitter. It just depends where you input your signal and where you get the output. In this case, both ways work at the same time.

[@ivansidorov6464]

As a guy who just got mobile techs bacelor degree I'm so glad to see someone teardown BS antenna and explain how it works

[@KaizerPowerElectronicsDk]

With some great help and corrections from commenters :)

[@shannybabayaga]

Wow, I have an interview for the base station antenna design engineer role next week and this was very helpful. I couldn't find much details elsewhere. Thank you.

[@p1366]

Good job! very interesting. It really shows how much anamzing design there is on the RAN side of the network to make up for the tiny antennas in our devices and the low power levels used in the uplink. Great to see how analog and physical it is to! Thanks for the video!

[@gammaleader96]

Very interesting, I love how every panel like this (every part number) seems to be built a little bit different with different elements and a different architecture. I have some of the bigger dipole elements with the more common "small sqares" in the middle. Also note how every color of semi rigid coax is a different impedance. Kathrein loves to use coax as transmission line transformers for matching all the different components. The coaxes are looped around the inside of the unit to keep the phase matched up, since every feedline needs to be the same - or atleast some known - length. The input diplexers are a piece of art and very stable. I wonder if anyone could come up with a design, that is as simple and effecitve. I guess these stripline designs are all autogenerated or atleast auto matched for efficiency. As Robberiffic said, they are a combination of filters and a power splitter. The upper dielectric makes them embedded striplines and also gives a higher dieelectric constant inside the enclosure. With a big airspace it is quite hard to keep oscillations down in such a enclosure with such high powers. All in all this sector antenna seems to be built quite a bit more solid than the ones I have seen. (also from Kathrein) Greetings, Michael

[@KaizerPowerElectronicsDk]

I have also had a few that was made from a wobbly tinned copper plates soldered together in smaller squared compartments. The copper antenna is however more worth in scrap than these aluminium ones are :)

[@gammaleader96]

@@KaizerPowerElectronicsDk That's treu as well. :) I still wonder why there is such a variation in build qualitiy or "massiveness" in these panels.

[@deantan9304]

Thank you so much for doing this teardown. I love watching this teardown and learn about the antenna from Kathrein/Ericsson Antenna System!

[@KDannie]

I just find your channel and I have to say I'm very excited and thankful for the material and how you show what is inside an antenna (variuos antennas) I really aprecciate how you explain all the things you know, easily. I'm working on my thesis about antennas and this helped me so much to understand so many things apparentely so difficult. Thank you so much!

[@KaizerPowerElectronicsDk]

Thank you for the kind words. Glad it could help you :)

[@santoshsinha9614]

Very good explanation of Base station Anatanna

[@unclecooper9409]

This is why I want to be an engineer

[@TomStorey96]

11:00 The Signal Path could probably explain it without even seeing it 🙂

[@gammaleader96]

But only after an initial catscan, just to be sure. ;)

[@TomStorey96]

Rewatching this video, and regarding your explanation of the radiation patterns, I remembered something I saw when I was in New York one time. Instead of the antennas being mounted vertically like you would normally see them, they were mounted horizontally and titled upwards to get signal into high rise buildings. So basically trying to cover a vertical space rather than horizontal space. I haven't seen this anywhere else yet.

[@KaizerPowerElectronicsDk]

That is an interesting observation, thank you for getting back to an old video with that! I have not seen that in Denmark, properly from the lack of densely packed high rises. Here we normally install local amplifier/antennas inside those buildings that can not be covered by the public networks.

[@dmitriyv4557]

Amazing video and explanations. Many thanks!

[@tamilchelvanramasamy8733]

Great demo Sir

[@KaizerPowerElectronicsDk]

Thanks You :)

[@klausnonn6357]

HEY , great video ...I gonna run the diplexer through CST...would you give the dimensions of the BOX (only the outer dimension and thickness) the rest (microstrip) i could generate myself...Thankz

[@KaizerPowerElectronicsDk]

Thank you, you will have to do with what you can see in the video. I do not have these parts anymore. The sandwich was properly 1 cm thick, two halves of 5 mm. I recall it being around 10x20 cm.

[@klausnonn6357]

@@KaizerPowerElectronicsDk GREAT! i'll give it a go PS: Both 900 and 1.8 get in TOGETHER , then the diplexer splits to respective antennas...i guess

[@PastoriciciRobertYO4HFU]

Beautiful

[@monkunderground4244]

Спасибо, очень интересно и познавательно.

[@StefanVanya]

magic inside :-)

[@AlonsoGonzalez]

I always thought the tilt mecanism where the whole antenna and not inside. 😅

[@muldoank8518]

I'm frm Indonesia Can i buy your kathrein??please

[@grubboy3514]

Voodoo and Black magic indeed...

[@franjordio]

Hi. Here "www.dropbox.com/s/ukyutem1831rwrf/KATHREIN%20DIPLEXER.png?dl=0" you will find a brief but easy explanation about how it works the diplexer. It's a rough explanation, because without passing it on an VNA or an spectrum analyzer with tracking generator, it's not possible to have a true frequency/amplitude response. Nice video.

[@pc-sound-legacy]

Thank you!

[@klausnonn6357]

i have a 3d model already , guessing PTFE dielectric but not to sure how to run it (CST)...should i put below 900mhz to 2ghz through the port alone on top...or vice versa...guessing it takes BOTH signals and separate to correspondent antenna...