The iPhone Forever Changed the RF Filter
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- Опубліковано 4 лют 2025
- Note:
I apologize to Lord Rayleigh for pronouncing his name like the American town Raleigh. It’s pronounced Ray Lee.
About my definition of Q factor: The cartoon you label the parameters on is a 2-port filter trace. However the Q I cited applies to a 1-port trace of an individual resonator.
The QORVO "filter fab" that I mention is not a filter fab. The real filter fab is in Florida and this image is apparently that of a packaging fab in China. Thanks to viewer Thomas for pointing this out.
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My thanks to an anonymous viewer of the channel for suggesting this topic. ❤ You know who you are.
Awesome video. Still hoping you will do a video on Atomera's MST technology. I think it will be the biggest thing to happen this decade for boosting semiconductor performance.
I find fiber optic to be faster. I do not use wireless at all. I use ethernet for my internet. I avoid wireless as much as I can.
Josh? (21:12)
I don't know who I am
I been saying the same. Go ATOMERA!!!@excitedbox5705
As an electrical engineer, RF is, generally speaking, the blackest art in the whole discipline. The tech that goes into making the RF front-end bits in modern smartphones is on a whole other level, though.
In addition to the craziness that is the filters you show here, I'd be fascinated to see your take on the incomprehensible antenna designs that somehow tune and work reasonably efficiently on six or more bands, or the power amplification and oscillator circuitry that operates clear through UHF and a big chunk of the microwave band.
I’d like to but I also want to stay sane.
@@Asianometry take a shot at it - would be great content.
Flat foil antennas - also a work of art. They fiddle with parasitic and transients to cover multiple frequencies, e. g. 900/1800 and ..850 or 1900!? Then they add a flat hooked L to the foil pattern shape for... Something else.
There are patents and I imagine a lot of inside art.
Almost witch craft . But then you see them tuning them sometimes with a scalpel by just cutting them
RF information is so difficult to find, especially highly detailed videos or websites that dig into formulas and practical examples. Making any frequency above 200 MHz and amplifying the signal seems to be impossible for me. Another hard piece of information to find is anything about radars that goes into detail.
My first engineering job was designing the "packages" for BAW resonators.
Your ability to digest and present highly technical and niche information like this is bordering on savant-like.
How about PAWG resonators haha
@@BBWahooLigma BAWs haha
Saddest thing is not a lot of people will realize the amount of effort that went into making a single RF filter, let alone the whole phone.
We've become a nation of users - where the average person has no idea what went into the things like their phone that they use.
People are very good at taking everything for granted
@@8__vv__8 true but its part of the progress and movement to simply get 'bored' of the already archived status quo
That's engineering for you. When you do a good job, nobody notices. Just the nature of the beast.
@@Zadster You get (if you are lucky) a few golf claps out of program management - but that's it.
Thanks for shining a light into this little understood corner of the semiconductor industry. Just a small correction. When someone in this industry says that a part cost $1.40 when purchased in quantities of 50 million, that does not mean that you get 50 million parts for $1.40. That means that you still have to pay $1.40 per part as long as you buy 50 million of them. So 50 million parts will cost you about $70 million. It is definitely incorrect to say that you can fill up a bucket with these parts for less than the cost of the bucket. It will be easily hundreds of thousands of dollars to fill up that bucket. I do hope you make a correction just so your viewers do not start to mistakenly short RF semiconductor stocks.
Yeah I laughed out loud at that. Based on that price, enough SAW to cover an entire generation of iPhone wouldn’t net enough profit to cover a single photomask.
I think most of the viewers should be clever enough to figure out that little aprils fool joke by themselves.
In the video's defense, it says that you can fill the bucket with RF filters for MORE than what the bucket costs
all I got from this was
Short RF Semiconductor stock.
say less king 😂😂😂
@@someone-mn8or Quoting the video, "...fill the bucket with RF filters for *MORE* than what the bucket costs."
Yep. I replayed the video to make sure what I heard, and yep - it's technically accurate. $70M is more than $2.
Thank you for not having background music
Remember when every video had swooshing sounds every time a slide changed?
This was my dad's field of expertise while working for GTE in the late 70's, after designing their 5 micron lithography library. He did a lot of SAW filter stuff for the military, including the radios used on the space shuttle. In particular, he told me how difficult it was to convince telecom companies back then to adopt any of the stuff they were making, including integrated circuits, because they were staunchly traditional and insisted on building their networks out of old-fashioned discrete components. Phone companies were always really bad at adopting new technologies, and for years, only the military was buying this stuff.
Eventually, GTE made a partnership with the Canadian telecom company Mitel, and things started moving into the consumer sector, but it wasn't too much longer before they went into market decline and got sold. GTE was one of the cutting edge giants back in the day that hardly anyone knows about today.
Amazing how far things have come, and how many companies (including Apple and Microsoft) totally missed the boat on the Internet revolution many decades ago.
What company is GTE?
digital.library.mcgill.ca/images/hrcorpreports/pdfs/6/637286.pdf
The Panavia (European) Tornado aircraft's GMR (Ground Mapping) RADAR used a SAW filter for pulse compression and de-compression in the LRU 4 receiver module IIRC ... a swept RF signal was sent in, and a longer, stretched signal spread in time came out, and vice versa on receive.
Your father must be proud of you keeping his stories alive.
Funny, too, how many people think that apple "invented" the "smartphone", when Nokia was doing web browsers and email for. *YEARS BEFORE APPLE!*
In fact, most of the technology in use today, originally existed inside Nokia... Was there, developed some of it
I would never have guessed that wireless communication goes through an acoustic stage like this!
Really interesting and not too niche for me at least. I remember when SAW filters suddenly became common in TV IF stages - ISTR it was not so much about performance as cost. They replaced several LC circuits which all needed to be hand-tuned in production, saving on parts cost, board size and manufacturing time. The IF stage became small enough to fit inside the tuner can, avoiding the need to have additional shielding for a separate IF stage.
And also every car and garage door remote control had a saw oscillator to get the size down.
@@Penfold42I think that was also about getting good stability cheaply - early keyfobs had nasty LC oscillators tuned by bending turns of a coil ( PLL synths were too costly and power hungry)
@@mikeselectricstuff so true. And often detuned by the person holding them !
wow, I though those things were solid state, but they're part mechanical, amazing.
The Zenith "M1" module comes to mind. We were using those in Dallas to decode subscription TV channels with an add-on digital board that did sync restoration and video inversion, as I mentioned, this was a subscription (pay) service.
This is my personal account (hence the profile pic), but I currently work for Qorvo at their Hillsboro, OR site. Qorvo was formed from the merger of Oregon-based TriQuint Semiconductor and North Carolina-based Radio Frequency Micro Devices (RFMD) that finalized in 2015. TriQuint manufactured SAW/BAW filters and other devices for Apple's iPhone line until 2015, and Qorvo continues to manufacture multiple components for a variety of customers around the world, and many of these are focused on RF technologies. Thank you for all of the work you do to create these videos. Even though I work in this industry, my slice is very narrow, and your content has been both extremely entertaining and legitimately useful.
What did you guys at TriQuint do with the Dallas Tx division that was doing GaAs MMICs? I worked in the group on the 90's.
It's quite the coincidence that you posted this video today. T-Mobile US is about to decommission their GSM1900 network on April 4th 2024. Meaning you can no longer connect to a network with any phone made prior to 2015-ish, which absolutely breaks my heart. This was the last remaining operational 1g, 2g and 3g network in the United States, and the longest continuously running cell network in US history. Meaning that even an old Nokia 2190 from 1994 still connects to the network today and works just as it did in 1994 (so long as you have an older pre-5g sim card). I still enjoy using old phones, like the HTC Dream (Google G1) and old Nokia/Ericsson phones, but come mid next week, that's all gone forever. Truly sad....
Same thing is happening in Australia, farmers are not happy because of coverage issues.
We're not alone. This shirt-pocket Sony Ericsson goes back 15 years. It'll be like throwing out a favourite smoking-jacket.
Bring on n71
I think this rectifies itself once they start using the old 2g frequencies for 5g.
Really well done! I should mention that a 40-band phone may not have 40 filters since the baseband bandwidth has also increased. Now, some filters may encompass multiple bands. Its a complicated trade off that considers RF interference, cost, complexity, regulations, and performance.
re: "a 40-band phone may not have 40 filters"
Yeah, many of the bands are adjacent, so, one filter covers multiple so-called 'bands' ... this is getting into the weeds though now.
Baseband scalable filtering applied. As well 40 bands sometimes logical terms since different technologies use same frequency allocation, but have different number assignments.
@@eugen19 One observation that was made, maybe 10 or 15 yrs back on an iPhone, we found that a 2 Watt or so UHF radio in transmit within a couple feet would force the iPhone to 'lose the call' (drop) in progress ... we theorized the strong UHF signal perhaps overloaded the wideband front and even with 'filtering' before it, so filtering is never absolute in function, its a relative thing, with the skirts still allowing some signal ingress into the phone.
I used lots of ceramic SAW filters for analog TV and radio receiver for IF frequency (455 kHz, 10.7 MHz, 45.75 MHz) from Murata. Before SAW filter, we used bulky ferite core coil in square metal can. One good thing about SAW filter, other than high-Q and stability, is it does not need center frequency adjustment, which need time-consuming manual labor. things of that old days with IF coils. But BAW is new to me. I didn't work for mobile RF.
Maybe you could do a video on the history of antenna designs, ending with cellphones or satellites. I researched this a few years ago and was surprised to learn the size and shape of the antenna in the iPhone and how such antennas were developed.
A modern multimode antenna design is actually a specially selected magical sigil corresponding to the most appropriate demon for the application; electrical signals activate the sigil, calling forth a tiny demon inside the phone, radio, or somesuch communication equipment. The demon is handed a very small letter containing one or more data packets. The demon then steps over to the recipient equipment sigil instantaneously. After the demon takes a short cigarette break to impart the appearance of a lightspeed propagation delay (these breaks are a condition in their employment/capture contract, and if these break times are withheld in the name of improved corporate efficiency, say, or maybe in a shortsighted effort to create a superluminal network, the demons get angry and go on strike and start bashing about breaking all the fragile things we tend to enjoy, like airplanes and time and global causality.) At the appropriate time, the demon places the letter upon the receiving sigil, whereupon the letter disintegrates into a quite beautiful puff of brightly colored particles with an astonishingly short half-life - so short, in fact, that they nearly always expire an infinitesimally short time earlier than they are created. Sadly, though known to be of exquisite beauty, this means they are invisible, thoroughly undetectable by any means, ever, and have never been witnessed. Despite this author's allocation of a significant portion of this paragraph to their detailed description, these particles are completely irrelevant to the sigil based communication system, of course. Under the cover of this completely invisible and useless smokescreen, the demon deftly extracts the letter contents before it vaporizes, hides it up his sleeve, and then slowly backs up in a very suspicious and conspicuous manner toward the baseband processor, and, once he believes nobody is looking, opens it up, shakes out a jumbled collection of 1 and 0 binary bits from his sleeve, closes the processor, and sneaks away. Thus are delivered the contents of the data packets to the recipient device. Of course, though all the bits are accounted for typically, owing to the incompetent data integrity measures inherent in a demon's shirt sleeve, the bits are in random order and better approximate a digital sampling of thermal noise than the desired message. As they are utter bunk now, the baseband processor simply deletes the received bits and replaces them with a perfect, in-order copy of the original message, using magic.
@@CassadyRoop Um, well, not even close, but, you do you - 'k?
@@CassadyRoop Best description ever :)
@@CassadyRoopI knew it!
@@CassadyRoop 😂
I think I *just* figured out why I like your videos so much.
You teach me new things every video, and you do so without assuming I know nothing in advance, but also don’t drop down the rabbit hole detail wise - while cautioning me when you do need to gloss over complex issues. 🙏❤️
I had some RF classes in college (EE), but didn't end up specializing in that field. Even our RF prof often called it dark sorcery. This was a very fascinating and welcome trip down memory lane, great video!
What's amazing is the dimensions these RF filters have become. They were much larger in older radio transceivers
Excellent as always. Your channel is a diamond in the rough.
This brings back happy memories of my days in the piezoelectric technology department at Bell Labs in North Andover, MA in the 1980's and 1990's. Lucent eventually sold off the whole business to Vectron in New Hampshire. One of the things not mentioned in the video is why SAW and BAW filters have become less popular in mass-market consumer electronic devices these days. And that is because these RF filters don't integrate well with silicon integrated circuits and that increases cost. One is forced to go off-chip for part of the transceiver chain and return back on chip. Instead, low/zero-IF architectures are used. But these filters can offer very high selectivity because the inherent high-Q of quartz on which they are built in applications that require them. So they'll always have a place in electronics. Even cheap 32KHz watch crystals can keep accurate time to within seconds/year.
As a ham operator, I feel seen! Lol. Since a lot of hams experiment in the HF bands, they still tend to use coils and capacitors, but, as software defined radios allow small packages to transmit and receive higher frequencies, I'm quite sure that the latest ham radios that do VHF, UHF and higher, are making use of some of the filters in question. The Icom 905 radio allows for Satcom/GHz experimentation, so a bunch of the filters you mentioned will be in that equipment as well. Great video! Thanks for the coverage!
DIM X[4999] # Input signal
DIM Y[4999] # Output signal
FOR I% = 50 TO 4949 # Loop over each point
Y[I%] = 0 # Initialize output
FOR J% = -50 TO 50 # Calculate summation
Y[I%] = Y[I%] + X[I% + J%]
NEXT J%
Y[I%] = Y[I%] / 101 # Complete the average
NEXT I%
As a former computer engineer who has worked on A/D, D/A signal processing I have nothing but awe for RF engineers. Glad to meet a lot of you here.
great video, thanks for posting. Always feel smarter, larger, after watching these precious gems.
You stopped so early! The story is so much more fun with OFDMA and MIMO thrown in.
Man, your videos are amazing. Amusing mix of history, science and easy to understand explaining. Thank you.
Wake up babe Asianometry just dropped a new video
Bot
@@volvo09 you win the prize! Huzzah!
never has this phrase been uttered 😂
Dead meme
Such a dead meme 😂
These videos are way beyond my knowledge base but I absolutely love them! Extremely well presented and loaded with fantastic details. Do I learn anything? No, but I still watch (and enjoy) every single video.
You have hit the exact issue that I have wondered about so many times.....this video was a home run for me. Thank you for all the work and then sharing.
Your radiophonic voice makes every subjects even more interesting to watch 😊
One interesting use of this technology is to modulate laser diodes and tune their frequency. One of these devices modulates the beam with data in the GHz range while the other one creates a diffraction pattern that picks the lasing frequency band. The entire assembly is tiny, but it allows the high speed data you know and love.❤
That's a cool idea.
Great presentation. For what it's worth, the S-A-W filter type I often hear pronounced in the industry the same way as the tool for cutting wood.
Thanks!
One big application for SAW type devices was TVs in PAL standard countries, where the technique was used to make 64uS quartz delay lines. They consist of a wafer of quartz with electrodes on two corners. The signal is injected at one corner, the acoustic wave bounces off the various edges, like a ball on a pool table, & ends up arriving at the other electrode to generate the delayed signal.
In school I am learning about electronic communication. It feels good to understand most of what you're talking about. Usually it's around 50%. This video is in the upper 80s. :)
Haha! What a great sport! (@10:35). Thanks for enduring our lashings. Take what you can use, and leave all the rest, etc. Thank you! 😊❤😊
I used to build and tune microwave waveguide filters, from 1900MHz to 11GHz. Those filters are waaaaaay bigger than filters found in your cell phones. This topic was interesting to me, Thanks.
Absolutely Fabulous video . This is a topic that I don't think I've seen anybody else cover. Great stuff.
for the first time of my life, I have read a full description of those broadband communication. Thank you so much
Interesting video. As an Amateur Radio operator and technology enthusiast, I find these RF and filter discussions entertaining. Thanks for the explanation of how these phones cover so many frequencies…
Please help to clarify the following statement:
"Nearly 15 years later, each filter cost between $1.40 to $1.60 when bought in volumes of 50 million units.
You can fill a bucket with these filters for more than what the bucket cost."
How much does the bucket cost?
How many filters does it take to fill a bucket?
I'll wait for that one comment with proper math, including fill-in ratio for 3 dimensional bucket
Yea, kinda suprised Asianometry dident noticed this himself when he read the script
Scriptwriter clearly fucked up. Someone read $1.40 to $1.60 and went 'ohh, thats cheaper than a bucket'..
Yeah that was either bad writing or a misunderstanding. He was describing bulk pricing but misinterpreted it as an insanely low unit cost.
Yeah, even I was caught off guard by that
None of you thought about it for even two seconds, he said MORE than what the bucket costs. It's a joke. It flew like a Concorde above your heads. If the bucket costs $4, and filling it with filters costs $4,000,000,000, it costs MORE to fill the bucket than what the bucket costs. He did not say LESS. T_T
Just a heads up, I've been working on a video about saw filters for a couple months now. Will come out in a couple weeks hopefully
excellent piece, I work with SAW and BAW filters frequently for my work with software defined radios but i never knew the history, fascinating.
small correction though, UMTS(3G) was already (mostly) IP-based, only voice was still circuit-switched
I think you missed the analog vs digital switch. The first tiny handy phones in Japan were analog, utilising saw filters that kicked off the whole high volume drive. When I worked on radios in the early 2000 everything available was targeted to the handy phone that was in a battle with Ericson and digital 3g. The big player in multiband was improved front end receivers and digital converters, as all phones use digital filters to isolate the bands with the front end filters blocking the transmit signal from bleeding into the receive band, and reducing mix signals from showing up in the receiver and transmitter. There is no longer the concept of a pass band carrying the data from a single channel (like the analog tv channels). Linearity across the band is one of the critical features as it contributes to the performance of the digital filters. The antennas are also key as there are multiple antennas with their own front end modules. It's not quite as simple as presented, and 5g may be driven by further integration making traditional suppliers less necessary.
I spent a stint at DSC/Alcatel supporting the Japanese PHS (Personal HandiPhone System) VMC (Voice Mail Center) back in the 2000 timeframe ... I did maintenance programming on the code that interfaced with the ISDN PRI cards, the PCs that held the PRI cards ran scripts to prompt the caller for info, announce messages and so forth ...
This is such an interesting topig. I always wondered how they filter out the right bands in all the stuff thats in the air nowdays. i would have never thought they developed such beautiful chips that can filter out like 20 to 40 seperate bands. You are doing so great work and I enjoy each and every video. It is a treat to get to know all this background and manufavturing knowledge so easiely via your videos. Because when you work with higher level IT like i do you get out of touch with the fundamentals. Thanks! And keep up the great quality content!
As a guy who works with RF antennas as a test engineer, I thank the anonymous user for recommending this
Saw filters including fbar(created by agilent, spinoff of hp). I'm rf engineer and used that technology in mid 90, at least 10 years before apple.
Love the deep dive EE esoterica!
I'm really fascinated to see the advancements of LIDAR and other forms of technology that can help archeology and learning about undiscovered ancient sites, etc.
That would be an interesting topic. LIDAR investment has rocketed in recent years to target the automotive industry. I think it's tool soon to see who wins, but the story of Velodyne used on the first Darpa Grand Challenge through to some of the solid-state LIDARs availiable now would be really interesting. Tesla of course famously has shunned LIDAR and gone all in on cameras.
Some of the spinout technology has gone back into the traditional LIDAR markets.
Never imagined to see AlScN so fast into the mass produced devices.
I'm currently doing my PhD on AlScN for MEMS integration but in comparison to all the other piezo ceramics the material is still so young.
Not long ago I attended a conference about piezoelectric materials and a lot of people from a lot of large companies were discussing AlScN for 6G and beyond.
Surprised you didn't mention the IBM -> GlobalFoundries dominance in building RF for Quorvo and many other suppliers for the past 15 years. Fabbed in Vermont Usa, which was one of the earliest Fabs in the world. Very interesting innovations in creating deep trench and air gap isolation for their time.
Ibm/Gf's innovations are kind of the whole reason that Quorvo has been so dominant.
Another great video. Amazing breath in topic coverage here.
I can remember Apple's antennagate nightmare PR scandal on release the iPhone 4 in June/July of 2010. The general public and news media did not realize how much more complex the RF in the iPhone 4 was over the 3G. (~16:00) The iPhone 4 SE had much more successful launch.
Thanks for this RF Filter video; just learned how much greater the complexity involved was than I'd imagined. (viewing data sheets doesn't reveal all the complexity inside)
Love the depth of the analysis and images :) well done
Brilliant video and commentary, an extremely fascinating subject to cover, thanks for the effort in putting it together - I've watched a few of your other video previously and now subscribed.
The pronunciation of Rayleigh just about unalived me.
Also "aluminium" from an American :D
My grandfather was one of the ones who pioneered these filters. Surprisingly I never saw his name or patents listed in this video, but essentially he made the patent that actually took off. Most phones nowadays use tens if not hundreds of these filters, but they're all on a single chip.
It is at moments like these that somebody notices it can be done in a completely different way at higher frequencies.
My electrical engineering professor at university used to work for Infineon in the team that designed the RF filters for the iPhone. Listening to his stories is very cool and interesting.
Basically Apple approached them like "hey, can you build us something like that?" And they got to work and made it happen. For multiple iPhone generations. Complete madness.
The people working on this kind of RF tech are beyond smart.
I do some RF work myself, but these guys are true masters at their job.
Fantastic video! One of your best. I enjoy that you go into such detail. I learn so much from all of them.
Absolutely - we are saturated in RFI, especially in the city. Signal to noise ratio baby, DC to daylight! Blows my mind how lithography is doing everything these days, and software is doing the rest, eg software defined radio....
DC to daylight indeed. Imagine if you could see all the wireless waves 😮
Excellent presentation on what every cell phone is equipped with. And there will be more radio transmitters.
I love opening these things up and putting them under the microscope! They look very beautiful! In terms of Q factor traditional cavity and helical filters are still the best. And you can make those at home, unlike SAW filters :D
All hail RayLa! Snark aside, your work is appreciated. Thanks.
Would love to see more deep dives on various MEMS!
Audio beamforming...
Keep going dude there is a lot more to this topic that is crazy interesting.
You can just say “saw” and “baw”. Everyone else does. Source: work in this specific industry.
Also 50M parts for $1.40 is a whopper untruth. I think you confused bulk pricing per unit with order pricing. A product run capable of covering an entire generation of smart phone wouldn’t cover the cost of a single photomask for said filter if $1.40 bought 50 million units.
He says"each filter can be bought for $1.40 to $1.80 when bought in volumes of 50 million" so I think he has it right, but then I don't understand the statement about the bucket.
@@snorman1911 yeah and as someone else pointed out he says “more than what the bucket costs” then said he felt bad for the manufacturer’s profit margins. It’s just a dumpster fire series of sentences. lol
That is seventy million dollars not one dollar and fifty cents for fifty million units?
@snorman1911 It's not your average bucket. 😁
@@Grak70 it was a joke
Acoustic (mechanical) filters have been used long before SAW in multi-channel wire (coax) long haul communications with frequency division multiplexing. They used magnetostriction effect of ferrites.
Yes to future Taiyo Yuden episode.
FWIW, the American town "Raleigh", in North Carolina, is pronounced more like "Rall-ee" like WALL-E, not the way pronounced in the video. :)
Apple is good at claiming firsts, and I do like their phones, but LTE was a thing long before iPhone 5 with both Samsung and HTC with popular devices a solid year before the 5. Not sure if you actually think the iPhone was responsible for changing the filter tech, or you're just playing the populist title game, but I felt this deserved some clarification.
poor colonial type, it's Ray-Lee, as in the General, or the river on the Essex county border. There are videos on Rayleigh, Essex, wot someone was the Lord of, and an Adele song on the river.
@@AndrewRoberts11 Hey, imagine that. Words are pronounced differently in the US vs UK. Next you know, you'll be telling me there are additional "u"s in the UK spelling of words as well. :P
In any case, the city in the US is "Rall-ee" or "Rah-lee" with a short "a" like "ball" or "wall".
@@Psychlist1972 Type "how do i pronounce RAY" into any respectable search engine, even colonial ones, will they likely only offer minimal variation. As to Leigh, Lee, Lea, or the half dozen other spellings, there's a Wikipedia page on the etymology of the River's name, though try Lee as in General Lee . With a bit of effort you'll soon be pronouncing "John William Strutt, 3rd Baron Rayleigh" like a local.
@@AndrewRoberts11 Why are you continuing to argue this? I'm not talking about the person, I'm talking about the city in NC, as stated in the comment you replied to.
@@Psychlist1972 The video refers to the 3rd Baron Rayleigh, though he was born a few miles NE, and died a few miles NW of Rayleigh, Essex, far closer to Guglielmo Marconi and Henry Ford's Essex mansions. Have wondered whether Marconi set up shop, building the world's first Radio factories in the area, simply to have Rayleigh as a neighbour, or was it just the accessibility to London.
Thanks for giving yet another glimpse into the Industry, which is hardly ever explained... Fascinating.
I loved my job as an rf engineer. We made passive filters for cable and internet providers. I miss it so so so much…
The bucket thing broke my brain :P Great video as always!
Hi Jon. Love your work.
btw 'Rayleigh' is pronounced RAY-LEE.
And, referring to the note in the description, that's not how the geographical location "RAH-lee" is pronounced either.
Did you get a new mic? Your voice has more depth than usual.
I wore headphones and felt him in my soul
Definitively not a piezo-electric or mems-microphone. Microphones is a fun topic, though. You can do insane things with arrays of mems-microphones, but for reproduction of the human voice or musical instruments, a cluster of designs from about 90 years ago, the capacitor, the moving coil and the ribbon element microphone transducers are still prefered.
Great channel !!
However this vid a bit misleading in discussing Q as a figure of merit for bandpass filters.
For single channel applications high Q is definitely superior, and can reach E7 or 10 million.
The Q of a bandpass filter is an accident of legislation. 5G bands are different in different countries for example
Europe :
3400-3800 MHz
USA :
3100-3550 MHz
So frequency legislation defines the Q.
For a bandpass filter the ideal is a "brick wall" which has no loss in passband and infinite loss outside passband.
In our finite world this is never possible.
The relevant figure of merit for passband filters is "shape factor" which compares the filter width at 2 different levels of attenuation like -3dB in passband vs -60dB in stop band, where these levels are tailored to the application.
The shape factor describes in real world how close ye are to the ideal "brick wall"
Keep up the MityFine work !
Cheers !
Payne
i wish i watched this when starting my career 12yrs ago. it is so interesting to see all those company's past history
r.i.p. lg mobile comm. department
Absolutely fascinating. RF is magic, you did a great job explaining it. Thanks.
I had a conversation a few years ago with an RF MEMS engineer who worked on BAW filters for Intel, it was fascinating.
Amazing video. Feel free to do more videos on anything RF related. There's just not a lot of information on the internet because no one has the knowledge or expertise to do it.
This complexity is really unexpected. For some reason I expected that it's all SDR's and tunable filters and was a little annoyed when phone for Chinese market was not supporting all needed bands in Europe. What I was also fascinated about is cryocooled superconducting RF filters for base stations. Exciting that it was possible to push it to commercial projects (as well as putting Rubidium atomic clocks in base stations in pre-GPS era).
You Sir, make me want to take notes, 20 years after leaving the educational system.
Learned SAW devices at my uncle's knee. In school he worked on that Voyager device and then racked up dozens of SAW device patents over his career. SAW is pronounced "saw" and BAW is "baw" (if that wasn't a word it is now ;-) "Piezo" is "pea-yay-zoh" meaning "to sit upon" (pressure).
pea-ay-zoh, sorry to nitpick
No shock that Broadcom’s RF filters are made in Fort Collins, CO after you mention that HP instruments created them, spun out to Agilent, then sold to Avago, then merged with Broadcom. HP has had a presence in the area for over 50 years iirc.
The other component you can maybe explore in future videos is the RF mixers/modulators and the A/D, D/A behind these filters. And why they require these filters to function.
Still waiting for the mythical GHz RF sampling ADC which can sample everything without needing analog filters or mixers. They consume too much power and can't handle the linearity requirements currently.
To elaborate on Q (quality) - in traditional LC (inductor-capacitor) filter design, Q is the filter's characteristic impedance (sqrt(L/C)) divided by the equivalent loss resistance.
RF, the black art of the EE world ! Radio was the initial "killer app" which propelled electronics for decades, thru the vacuum tube days, and into the semiconductor era. Then things got side tracked, when semiconductors could make these computer thingies cheap, yet powerful, at the same time. Digital became all the rage. But its come full circle, where your smartphone is a merging of both computer power, and RF finesse. Look at these filters ! If that's not black magic, I don't know what is !
I worked for Siemens-Infineon when I heard 1st about BAW filter. What a pity that again something great was invented in Germany but lost far too early to the competition.
We actually started using SAW devices as sensors in some new Defense Aerospace systems
In the end, the BAW filter is just like an incredibly miniaturized Collins Mechanical Filter.
Very interesting - thanks for taking the time to understand it and explain it to us.
How in Mao’s name do you manage to pump out these videos so quickly
*Abstract*
This video explores the evolution of RF filters, focusing on the impact of the iPhone and the rise of LTE technology. It delves into the technical aspects of SAW and BAW filters, their manufacturing processes, and the key players in the industry. The video concludes by discussing the future of RF filters in the context of 5G and potential market trends.
*The Importance of RF Filters*
* 0:02: The video starts by highlighting the challenge of receiving desired radio signals amidst a sea of radio noise. RF filters play a crucial role in ensuring clear communication by selectively allowing specific frequency bands to pass through while blocking unwanted ones.
*Filter Basics and Functionality*
* 0:53: The fundamental function of a filter is explained, emphasizing its role in passing desired frequencies and rejecting unwanted ones.
* 1:24: The concept of "insertion loss" is introduced, representing the unavoidable signal degradation caused by filters.
* 2:03: The video defines the "Quality Factor (Q)" as a metric for evaluating filter performance, with higher Q values indicating better selectivity.
* 2:39: The focus narrows down to RF filters operating between 100 MHz and 10 GHz, differentiating them from microwave filters.
*SAW Filters: Early Development and Applications*
* 3:07: The historical origins of SAW filters are traced back to Lord Rayleigh's work on surface acoustic waves in the 1880s.
* 3:58: The invention of "Interdigitated Transducers (IDTs)" in 1965 is discussed, marking a significant advancement in SAW filter technology.
* 4:45: The video explains the working principle of SAW filters, where IDTs convert electrical signals into mechanical waves and vice versa using piezoelectric materials.
* 5:42: The manufacturing process of SAW filters is described as a MEMS (Micro-Electro-Mechanical Systems) technology involving deposition, lithography, and etching.
* 7:10: Early applications of SAW filters in military communications, space exploration (Voyager missions), and television sets are highlighted.
*The Rise of SAW Filters in Mobile Phones*
* 8:33: The transition from bulky ceramic filters to smaller SAW filters in mobile phones during the development of 2G cellular networks is explained.
* 9:11: The video emphasizes the affordability and ease of manufacturing SAW filters, making them a dominant choice for early mobile phones.
*Limitations of SAW and the Emergence of BAW*
* 9:34: The limitations of SAW filters at higher frequencies above 2 GHz are discussed, leading to the need for alternative solutions like BAW (Bulk Acoustic Wave) filters.
* 10:40: The video introduces BAW filters, which utilize acoustic waves traveling through the bulk of the material, offering advantages in higher frequency applications.
* 11:15: The two main types of BAW filters, FBAR (Film Bulk Acoustic Resonator) and SMR (Solidly Mounted Resonator), are briefly explained.
*FBAR Filters: Advantages and Manufacturing Challenges*
* 13:41: The video delves into the benefits of FBAR filters, such as better electrical isolation, reduced sensitivity to contamination, and suitability for higher frequencies.
* 14:07: The manufacturing complexities of FBAR filters are discussed, including the need for multiple mask layers and precise thin-film deposition techniques.
*The iPhone and the LTE Revolution*
* 15:37: The video explores the transition from SAW to FBAR filters in iPhones as they adopted LTE technology with its numerous frequency bands.
* 17:10: The iPhone 5's role as a "world phone" supporting multiple LTE bands is highlighted, driving the demand for advanced RF filters.
* 18:50: The significant growth of the BAW RF filter industry following the LTE rollout is emphasized, with Qorvo and Broadcom emerging as dominant players.
*The Future of RF Filters: 5G and Beyond*
* 20:11: The video discusses the challenges and opportunities presented by 5G technology, requiring further advancements in BAW filter design and materials.
* 21:13: The potential for continued growth in the RF filter industry is explored, considering factors like increasing demand for higher frequencies, miniaturization, and performance improvements.
i used gemini 1.5 pro
Token count
10,925 / 1,048,576
*Top UA-cam Comments on "The iPhone Forever Changed the RF Filter":*
* *Praise for the Video and Channel:* Many viewers express appreciation for the informative and engaging presentation of a complex topic, praising the channel's ability to make technical subjects accessible and interesting.
* *RF Engineering Insights:* Several comments come from RF engineers or individuals with experience in the field, sharing their own perspectives and anecdotes related to RF filters and the broader world of radio frequency technology. They often highlight the complexity and "black magic" aspects of RF engineering.
* *Technical Clarifications and Corrections:* Some viewers provide technical clarifications or corrections to certain points in the video, such as the pronunciation of "Rayleigh", the definition of Q factor for bandpass filters, and the actual location of Broadcom's RF filter fabrication facility.
* *Historical Context and Industry Evolution:* Comments discuss the historical development of RF filter technologies, including the contributions of companies like HP, Agilent, and Infineon. Some viewers share personal experiences and memories of working with SAW and BAW filters in various applications.
* *iPhone's Impact and Market Dynamics:* Several comments debate the extent to which the iPhone truly "changed" the RF filter industry, acknowledging the influence of other smartphone manufacturers and broader market trends like the rise of LTE.
* *Future of RF Filters and 5G:* Viewers express curiosity about the future of RF filters in the context of 5G and beyond, speculating on the potential for further miniaturization, integration, and the use of new materials like scandium-doped aluminum nitride.
* *Requests for Future Topics:* Numerous comments suggest ideas for future videos, including antenna design, other MEMS technologies, the history of specific companies like Taiyo Yuden, and the use of software-defined radio for filtering.
*Companies in the RF Filter Landscape:*
*Major Players:*
* *Broadcom (formerly Avago):* A key innovator and manufacturer of BAW filters, with a significant market share. Their RF filter business originated from HP/Agilent and later acquired Infineon's FBAR research group. They currently fabricate filters in the United States.
* *Qorvo (formed from TriQuint and RF Micro Devices):* Another major player in both SAW and BAW filters, holding a substantial portion of the market. They have a history of supplying filters for iPhones and other mobile devices.
*Other Notable Companies:*
* *Murata:* A Japanese company known for its SAW filters, with a strong presence in the mobile phone and consumer electronics industries.
* *Skyworks:* A semiconductor company specializing in RF components, including SAW filters, for mobile devices and other wireless applications.
* *Taiyo Yuden:* A Japanese manufacturer of SAW filters and other electronic components.
*Historical and Related Companies:*
* *Infineon:* A German semiconductor company that played a crucial role in the early development of BAW filters, later selling their FBAR research group to Avago.
* *HP/Agilent:* The origin of Broadcom's RF filter business, with early research and development in FBAR technology.
* *Motorola:* Pioneered early mobile phones like the DynaTAC, which used ceramic filters before the adoption of SAW technology.
* *Philips, Plessey, Siemens:* Early adopters of SAW filters for television sets, contributing to the mass production and cost reduction of these devices.
*Additional Mentions:*
* *GlobalFoundries (formerly IBM):* Mentioned in the comments for their role in manufacturing RF components for Qorvo and other suppliers.
* *Intel:* Briefly mentioned for their past involvement in BAW filter development.
* *NXP (formerly Philips):* Highlighted in a comment as an example of company name changes and industry consolidation.
* *T-Mobile:* Discussed in the context of shutting down their GSM network, impacting older phones that rely on SAW filters.
The video and discussion showcase the complex ecosystem of companies involved in the RF filter industry, highlighting the contributions of both established giants and specialized players. The industry has experienced significant consolidation, with Broadcom and Qorvo emerging as dominant forces, while other companies continue to innovate and compete in various segments of the market.
I worked in thin film MEMS wafer fabs for HDDs and also studied communication theory in my masters, and love this interesting history and how capitalism drove innovation within my lifetime … Also, as someone who splits time between the USA an Asia, I am glad I can just use one phone.
The stuff we can do with MEMS these days is astonishing. Thanks for another great episode!
Great video , packed with information.
Should do a video on ultra wide band filtering technique or even just UWB pcb inductors!
I read about SAW filters when they first appeared years ago, but had no idea that they and their offspring were at the heart of our modern phone world. Fascinating report!
Wow, if you do antenna tuner switches next maybe I'll be able to explain to my family the stuff I work on 😂
Interestingly, the MEMS devices inside iphones make the phone susceptible to helium gas which can soak into the filter, changing the resonance frequency of the nanomechanical resonators as helium has a higher speed of sound. Famously, some iphones died in MRI and NMR labs while their superconducting magnet was filled with helium...
9:29 "You can fill a bucket with these [low cost] filters for MORE than the bucket cost." Buckets usually cost very little. This doesn’t make any sense. What is the point of saying that? If you meant ‘less’ than the bucket costs, that would be saying something. But at a dollar and a half a piece and being very small, this just feels like a pointless statement. I feel I must be missing something…
SAW (Surface Acoustic Wave) has 3 popular application space: filter, delay line, and resonator (
"Inside a SAW Filter"
Wait a minute...
we transform electrical signals into audio signals back to electrical signals and
the loss during the transformation is basically the filter.
Have i understood that correctly?
Correct
No, the loss is the unavoidable side effect.
Applying a signal outside the resonator frequency just doesn't generate these waves so they don't make it to the other end.
Put "selectively" in front of transform. Change "audio" to "mechanical"? Delete the loss sentence. Loss here means look somewhere else for perpetual motion machine :)
In this case mechanical is adiabatic acoustic energy propagation via a surface mode wave. (Acoustic does not mandate audio. Aka all dolphins are whales, not all whales are dolphins)