TSP

День тому

In this episode Shahriar explores the principle operation of automotive FMCW radars. Thanks to a donated automotive radar module, various components of the system can be examined and explored. The PCB reveals three die-on-PCB ASICs responsible for generating and receiving 77GHz FMCW signals coupled to a 2D array of antennas. Several microwave components such as rat-race couplers and branchline couplers can also be observed. PCB rulers from SV1AFN Design Lab (link below) also show these microwave components at much lower frequencies. Two other ICs are used for ramp generation and PLL as well as a multi-input LNA/PGA/AAF with 12-bit ADC for IF processing. All components are examined under the microscope and the frequency of operation is calculated by measuring the branchline coupler's dimensions.
Finally a simple Doppler effect radar is constructed by using a doubler, power divider, mixer and a pair of Vivaldi horn antennas. The Doppler effect can be observed by moving an object in front of the antenna pair.
Get your microwave ruler here:
www.sv1afn.com/pcbruler.html
The Signal Path
www.TheSignalPath.com
/ thesignalpath
www.Patreon.com/TheSignalPath

КОМЕНТАРІ: 122

@Fake0Name 7 років тому

TFW Shahriar's cat is a better RF engineer then I am.

@Fake0Name 6 років тому

Has anyone told you you're kind of a jerk? You are sure acting like one.

@SnowIsMyTerrain 7 років тому

In case anyone is wondering: The circuitry on the second board was some bus related stuff for CAN, a high performance TI Sitara, a DSP IC, DDR3, and the power circuitry. I'm a dumbass and pretty well destroyed the 2nd board (as you can see from the connector w/ random PCB bits attached) hence it's lack on inclusion in the package.

@laneboysrc 7 років тому

Thanks for sending the unit in, that was very interesting to have an expert like Shahriar to go through it!

@everythingquads 2 роки тому

Very rarely when a UKpostsr says something will be interesting and exciting, it actually is. I'm excited everytime I see a notification for a Signal Path upload.

@moshet842 2 роки тому

What I love from your videos is that even though the concepts are advanced, I still end up learning something. In this case, I got an understanding of the doppler effect that I've heard about many times.

@projectartichoke Рік тому

Love the content here. You really have a knack for making complicated subjects understandable. You'd make a great teacher.

@glenwoofit 7 років тому

Absolutely fascinating. I'm gutted there were parts you couldn't talk about but its understandable. I love it when people explain RF circuitry it's way above me but you explain it so well even I get to learn stuff. Thanks for the marvellous videos.

@piranha32 7 років тому

Thanks for another great video! Could you please create a separate episode explaining how those magical microwave PCB components work? I know that you mentioned them at different occasions, but it would be helpful to have one video with all the knowledge in concentrated form.

@JanCiger 7 років тому

Thanks for a very good explanation of FMCW radar - I remembered it was something like this but you really made it "click" in place!

@-r-495 4 місяці тому

Just watched the most recent one and I found this one. Great work, you help me concentrate on something else than what tries creeping up.

@symik3 7 років тому

It is a hole different world than what i am used to, amazing. I would like to watch more tutorials into RF stuffs. Nice video.

@Daniel-ib5bx 6 років тому

Awesome video as always thank you!

@melkhoulyihp 7 років тому

Great episode Shahriar. great explanation for the microwave structures on the PCB I have to say this is a bit old system. The new systems the chips are packaged with technique called eWLB and they are soldered on the PCB like BGA Furthermore, the new generations the frequency generation is integrated with the TX front-end

@pasupuletivenkatesh4642 2 місяці тому

superb explanation

@DoRC 7 років тому

2 in one day!?!? what a treat:)

@TheIncrediblevideos 6 років тому

Good to see ECU which i am working on is featured in this video. This ECU is developed by delphi indeed.. It is called electronic scanned radar

@irawarnaca8133 6 років тому

Thank you for the great video. I'm very interested in the self-driving car technology.

@NavarroEletronica 7 років тому

Shahriar, if you teach about microwave on your channel I really think it's going to be one of the best explanations.

@AF6LJSue 7 років тому

Great Video

@aruldeepa9006 3 роки тому

Very informative thank you

@lmamakos 5 років тому

Pooch is once again the star of the show

@cetola 7 років тому

Awesome video, thank you for all your work here. One thing I missed was at 11:29 - "Infineon {something} CMOS... so they're just {acronym} process". Thanks again!

@cetola 7 років тому

Perfect, thank you!

@douro20 7 років тому

I've seen designs for acquisition boards for the Large Hadron Collider which used COB technology for the custom analog chips.

@hcovic 6 років тому

just great

@pa3bca 7 років тому

switch the SA for a scope when looking at the output of the mixer. For those interested: get a cheap HB100 10 Ghz unit through ebay and experiment with doppler radar yourself. Oh and btw I very much appreciate your video's.

@chandrasekar3653 5 років тому

hey i have just started to enter into this radar thing , found this video and to my surprise this is awesome , even though i am not able to understand any of the technical components that you were mentioning (dont even know what is a coupler ) i am enjoying it . can u mention how do i start of from the basics to fully understand these radar things so that i can be able to build my own FMCW radar

@billybunter9103 6 років тому

very interesting

@johnjr5599 5 років тому

Shahriar, at around 7:49 when you’re explaining the ramp up and ramp down, isn’t the graph on the left representative of what would be received if the object is moving away from the vehicle/transmitter? The picture shows the object moving towards. Based on the doppler effect a pulse should be frequency shifted up if the object was moving towards the vehicle, but the peak of that graph shows the received pulse as a lower frequency than the transmitted pulse. Is this correct or am I missing something?

@daniraphaeli440 6 років тому

Dear Shahriar, At the unused end of the coupler and the edge of unused lines there should be a 50 ohm termination. I don't see any termination there, please explain where is the termination or how it is going to be 50 ohm?

@ZEROSTATIC72 7 років тому

Interesting test equipment with the extra sweeping tail. Thanks for the very interesting video, it's a pity that you couldn't talk about the signal coupling to the antenna array. :-)

@trevorvanbremen4718 2 роки тому

That sweeping tail is an idea that Shariar should patent... Perhaps name it 'The Cat Scan'???

@user-vw6gv6xu6t 8 місяців тому

The ADC is a 6 analog front end channels multiplexed into a single ADC, so it is not a simutaneous sampling system. How to handle this in the system point of view? Thanks a lot!

@Sixta16 6 років тому

Love your cat!

@correodefelipe 2 роки тому

Hi, I'm willing to buy two of these radars to do TxRx experiments (no FMCW nor Doppler involved), but I'm afraid it will be tricky to obtain the measured reflected/transmitted signal since there is lots of tightly-packaged complex electronics involved. Do you think this is possible? what are the drawbacks and difficulties you can expect to find in this project? Thanks for the great video!

@akhilvijay8670 3 роки тому

super masss boss

@jayzinho10 3 роки тому

As usual the video was Amazing sir. Sir I would like to know how energy is being coupled to the antenna(phased array). Thank You 😊

@user-hj5nr3wy5w 2 роки тому

Love the video. I couldn’t find the link for the custom rulers.

@cam3oh 7 років тому

Just a quick thing to point out. At 9:10, you point out that the top cover has to be plastic to be transparent, but as I understand it, you want to have the thickness such that it works as a 1/4 wave transformer. The plastic is better for reducing attenuation through the medium though, which should in theory mean a wider bandwidth, right?

@kaustubhharapanahalli3666 6 років тому

Hello, can you please give me any kind of details on where I can buy a 77 GHz radar module either online or in a retail store.

@keshabapatel8322 7 років тому

Hi Sharihar... Could you please tell the manufacturer of the radar module and also the vehicle it is used.

@aghorash 6 років тому

Does anybody have a link to more information about the "terminated points" at 17:26 ?

@yaghiyahbrenner8902 7 років тому

14:05 RF Black Magic Rulers. Sweeeet!

@yaghiyahbrenner8902 7 років тому

I just bought one.

@ShaharBenDavid 5 років тому

Is there a way to see the negative frequencies on a spectrum analyzer in order to extract the relative motion direction?

@ryanwans391 2 роки тому

Nope. In most doppler radars, they will use an additional mixer between the CW source and RX mixer with an IF clock to raise the RX IF baseband. That way, you'll be able to see both up and downshifts in freq.

@HSPalm 7 років тому

Any reason the vias are not tented?

@mman454 7 років тому

It's the start of the video I see a cat sitting on top of an oscilloscope that costs in the five to six digit range, and my eye just starts to twitch.

@Thesignalpath 7 років тому

That's his favorite spot!

@rfengr00 7 років тому

Nice tear down! That antenna is a Taconic laminate. The Taconic rep brought it by on a visit. What's odd though is that the transmission lines are oriented parallel to the weave; IIRC the sample I saw had them at 45 degrees to keep it more homogenous. Those WR12 to microstrip transitions are pretty narrow band, but the don't require a back-short. I'm using a differential microstrip to WR15 on a board I just finished. Need a back shirt but much wider band, and can couple to the TX chip without a balun. Those rat race baluns aren't really baluns if you think about it, since there is no way to fully convert a pure differential signal to single ended with that structure; still requires a good amount of ground currents for the differential side. Notice lack of termination resistor on the branch line. They must be tapering it down to such high Z0 that it just leaks off. Anyway, good stuff.

@Thesignalpath 7 років тому

Thanks for your contribution! Why do you think that you can't convert to single-ended? Those interconnected appear to be microstrips.

@rfengr00 7 років тому

The Signal Path if it's a purely differential signal on the balanced side (i.e an infinite Zcomm) there is no way for that signal to induce a current in the ground plane for the single ended side. If you sliced the ground plane beneath the differential lines it would fail; at least that's what my EM simulations showed. The output stage of that TX chip can probably be run either single ended into 50 ohms or differential into 100 ohms, so it has a fairly low common mode impedance, which allows it to work with that rat race balun. A Marchand balun should work since it relies on resonance, and a tapered line balun, but then you'd need vias to the bottom of the board. You whizzed by me on the floor at IMS (either Phoenix or Baltimore), and I was thinking I have seen that guy on UKposts. Didn't get a chance to say Hi. Maybe at another one. Anyway, great UKposts channel.

@Thesignalpath 7 років тому

Yes, I agree that the output stage is likely quasi-differential and can provide signal into 50-Ohm single-ended. I am sorry that I missed you at IMS! I hope we can meet next time. :)

@rfengr00 7 років тому

The Signal Path for sure. Maybe in Philly next year. My company is too cheap for Hawaii.

@kl1nk0r 7 років тому

It is totally possible to convert a fully differential mode to a single ended mode by tapering the differential microstrip line to two single ended microstrip lines first and then combining then with ratrace couplers as done here! I work with similar stuff at a radar research institute in Germany and we do this on a regular basis in order to reduce parasitic bondwire inductance when compared to single ended bond wires. Funny, I ran into Shahriar at IMS back i Florida a few years ago when I was stil, a master student. He was really nice to talk to. I dont know if you remember me, but it is nice to see that you are doing well! We are also working with Infineon silicon processes.

@davidsanders5861 7 років тому

Hi Shahriar, I love this video. I have been hoping for a while that you would do something on FMCW. Do you have any plans for more videos on this topic? As a golfer and an engineer, I am very intrigued by radar devices (such as the "Trackman") that can track a golf ball's flight through the air and measure things like the rotational velocity of the ball, distance of travel and many other things. It would be cool to be able to do some experiments with stuff like this, unfortunately a lot of the components seem out of reach cost wise. Do you have any tips, or resources you recommend, on how to experiment with radar in the 10.5 GHz range without breaking the bank?

@IDoNotLikeHandlesOnYT 5 років тому

Doppler radar modules at that frequency are available from some online stores that cater to the DIY electronics market, and they're quite inexpensive.

@debapratimdhara6599 2 роки тому

These antennas are called comb-line antennas.

@PlasmaHH 7 років тому

Maybe you can negotiate with your superiors on what exactly you are allowed to discuss and go as far as any way possible?

@dabdoube92 8 місяців тому

Can't negotiate. That's conflict of interests. I sure hope he could though !

@gacherumburu9958 Рік тому

👍👍

@michelfeinstein 3 роки тому

How do you have all of these equipment at home? This could be more than a million dollars... Could you explain how you got them? Sponsorship? Remote work for a company? Do you own a company?

@jaideepbose8571 6 років тому

This is a good video tutorial for anyone interested in automotive radars, to know the fundamentals of range and Doppler shifts etc. The information (not)presented is too general for an RF engineer like me, and I could easily make out the RF circuitry and stuff! The microwave ruler maybe interesting but was not required in the presentation (so was the cat!); and I bet, you won't be able to build one commercial automotive radar unless you cover lot more serious stuff in DSP, beamforming, and phased array antenna system; so one should use the information here as preliminary. Nonetheless, a good attempt and the 'flow' is nice!

@leppie 7 років тому

Aliens!

@pauldeboer 7 років тому

Next time don't use an SA to show the result, just hook up an Audio amplifier. It just beats anything else to experience what happens when you wave the pcb above it.

@stargazer7644 7 років тому

Yes, I agree. An audio amp hooked to a simple 10 GHz gunnplexer will teach you all you ever wanted to know about Doppler effect. Take it out and point it at some moving cars, or a rotating fan blade, or interestingly, a lit fluorescent tube. The tones you get back are fascinating.

@mikeiver 11 місяців тому

Kinda bummed that he didn't do a deep dive in this module and the microwave magic that makes it tick.

@MilanNedic94 3 роки тому

17:35 Does any one knows more about this topic under NDA? Please refer me to some books/articles or at least keywords needed to lookup in order to understand all these goldy structures around the ICs. I am digital ASIC design engineer with FPGA background and I enjoyed undergrad Electromagnetics, I believe I'll find a way to understand this beauty. Thanks!

@ryanwans391 2 роки тому

microstrip to WR12 transition

@janisskujenieks3970 7 років тому

I think wire bonding is also used because of harsh environment in cars. Solder joints could brake after some time if not protected very well.

@samirt2339 6 років тому

Nice video. However, you began by saying that there is a “frequency shift” in the received ramp from a stationary object. Yet at the end, it’s clear there is not shift in frequency when the copper piece is stationary. There is however a “delay”. Good job, keep up the nice work.

@Thesignalpath 6 років тому

There is a frequency shift in a FMCW radar system from a stationary object because the input signal is FMCW. The delay translates to frequency shift with respect to the transmitted signal. In my test the input signal is CW and therefore no observed shift in frequency, only Doppler shift.

@sivalley 7 років тому

FoMoCo=Ford Motor Company? Willing to bet that came out of a Cadillac if my initial guess is correct.

@SnowIsMyTerrain 7 років тому

Nope, came out of a new generation F-150, Cadillac is GM not FoMoCo.

@sivalley 7 років тому

SnowIsMyTerrain Bleh. Not a car person, but at least I guessed correctly it came out of a Ford vehicle. lol

@DoRC 7 років тому

eh. Doppler actually lived to be an old man. Left expectancy around that time was 37 years.

@130090558 7 років тому

That's because so many babies died, people would either live to 1 or 61

@CodfishCatfish 6 років тому

Try a tuning fork. You will be surprised.

@fredfabris7187 6 років тому

I love Electronics, but this is magic not Electronics :-)

@fatthar4804 7 років тому

the cat is angry 😾

@Thesignalpath 7 років тому

+fat thar He is the happiest cat!

@NSAwatchesME 6 років тому

this guy sounds persian

@AxelWerner 7 років тому

you have lab-cats :/

@Thesignalpath 7 років тому

No cats, just one cat! :) Dr. Pooch.

@krawutzimon 7 років тому

even he has a PhD ;)

@NSAwatchesME 6 років тому

salum now i come back i do radar for missile goes boom

@101constexpr 5 років тому

What is the point of the video if you don't want people to learn what you know?

@lolkusus 3 роки тому

Why can't talko about it? Physics is not patentable.

@Thesignalpath 3 роки тому

Physics is not patentable. Implementation is however.

@pizzablender 2 роки тому

Knowing how the competitor is thinking is very important. "Oh, they think we did this to achieve ...? Never thought about that let's look into it".

@PushyPawn Рік тому

It's regarding Broadband E - Band WR12 to Microstrip Line Transition Using a Ridge Structure on High-Permittivity Thin-Film Material. Stuff you probably won't be able to follow.

@lolkusus Рік тому

@@PushyPawn now I am finishing my studies and can understand :P but yes, one year ago I could not