77Ghz / 24Ghz Microwave Radar Design - Page 1
Forum section: electronics / projects

author: Icarus
author_rank: Regular Contributor
timestamp: September 30, 2015, 04:15:08 pm
content: Hi Folks;My new employer wants me to design a 24Ghz Multi Target, 2D, Patch Antenna RADAR ! with 2km range.There is only one 20MHz Tektronix scope and a Fluke Multimeter in the lab.Is it possible design such thing with only simulation data ? no lab equipment. (I've never design a "F > 2GHz" thing before)How hard is it ? I think I should use a "off-the-shelf" 24Ghz radar front end ic + a DSP for signal processing. It seems to me above 20GHz discrete design is just not feasible.What is your advice ?

author: BFX
author_rank: Frequent Contributor
timestamp: September 30, 2015, 05:33:44 pm
content: "Nice" employerTry to ask on some near university or microwave lab if is possible to borrow machine time to tune your simulation.But I think it will be very hard work

author: LaserSteve
author_rank: Super Contributor
timestamp: September 30, 2015, 05:48:48 pm
content: The process involves simulators, prototyping, measurement, and returning to the simulator. 20 Ghz was done by hand before simulators, so it is possible.At the least you need a 30 Ghz capable spectrum analyzer, a vector network analyzer, attenuators, some circulators or isolators, 3 port tuner(s), detectors, and cabling capable of working at 30 Ghz, plus a few microwave reference horn antennas. I'd tack on a fixed crystal controlled 22-24 Ghz source to that as well. Attenuation in cabling is atrocious above 10 Ghz, so very high grades of phase stable coax and or waveguide are used for these types of measurements. The ones Agilent loaned us for the Ham Microwave conference were 3,000$ per meter.Do want steerable, or just multi-target ? This is not going to be easy, even with a chipset and evaluation board. You also need a controlled impedance circuit board, and need to keep with that low loss board material (Such as Rogers Duroid) all the way to final product.Now, Ham radio operators often run with a fraction of that to get on 24 Ghz ham radio, but they are usually following the "cookbook" design as much as possible. Yes, they even do it with stock SMD.Start with Sonnet Lite, its a free download, so you can see what your getting into.Hum, probably twenty thousand dollars (minimum) of gently used or rented equipment, or a lot more if bought new, is needed for your project. For everything New, your probably looking at 50-70-100K$ of startup costs in instruments and materials.A skilled person would get by with just the VNA and power meter and small stuff, but in your case you need spectral analysis. You might find a combo VNA/SA....Time to find some one with experience at 22 and find out what they suggest... My home ham lab stops at 12 Ghz, MY SA is salvaged and repaired junk, and I do not have a VNA, so I cant help you.Perhaps its time to call Bosch /Hittite, and/or others and get finished RF chips and modules you can work with? You'll also need a lot of regulatory compliance measurements etc..Start with FM/CW radar theory and work your way up to ranging codes, phase modulation etc...I'd make very sure I had a plan, and stated goals with my employer before starting this... Including the fact that 24 Ghz is being phased out in Europe, leaving 77 Ghz which is not for beginners.If you need gear for 77 Ghz, quadruple your budget or buy a module...Sounds like fun for a first major project in RF...Steve

author: daqq
author_rank: Super Contributor
timestamp: September 30, 2015, 06:05:10 pm
content: Normally this kind of stuff is designed by a team of people, at least one of whom is a serious RF engineer stroking a massive grey beard - anything above a few GHz is in the realm of microwave black magic and requires a LOT of knowledge.You COULD just get by probably, eventually hack something working together, that does vaguely similar, but it would take a LONG time.First thing: Education. If you don't know anything about RF, prepare for a few months bare minimum of intensive study, nasty maths.Second thing: Budget. Above a certain frequency, prices get exorbitant. As in several hundred USD for a simple cable (or waveguide probably). You can't use good old FR4, special materials come into play. This is still amusing when compared to the measurement equipment. But it sounds as you are limited to what your boss found on some garage sale - that measurement equipment is barely usable if you are making a cheap amplifier, not a bleeding edge radar. *Third thing: (Commercial) simulation software for that kind of stuff is expensive (as in several thousand or tens of thousands USD) and requires a lot of RF knowledge, otherwise you get a GIGO situation - garbage in, garbage out.I'm sorry to tell you this, but your best bet would probably be to hire some external consultant/company to do the whole RF part, while you can do the signal processing. Or buy the whole radar block.* - to be fair, you can get some amazing things off ebay for relatively cheap.

author: tggzzz
author_rank: Super Contributor
timestamp: September 30, 2015, 06:34:33 pm
content: Quote from: Icarus on September 30, 2015, 04:15:08 pmWhat is and is not implied by "design"?For a microwave (or millimetre wave at 77GHz) engineer, it might mean starting with a block of aluminium, some Duroid, transistors and CAD.For a systems engineer it might mean starting with a radar module, some SMA-terminated coax, a DSP module and an antenna.If the former, I'd do a feasibility study to scope out predicted performance, what's available off-the-shelf, and what skills and time would be necessary. And then let your employer decide whether asking you to do it is a reasonable option.

author: Icarus
author_rank: Regular Contributor
timestamp: September 30, 2015, 08:33:27 pm
content: Thank you all.I didn't know 24Ghz tech was phased out.One more thing, is there any health issue about this type of microwave radiation ?

author: German_EE
author_rank: Super Contributor
timestamp: September 30, 2015, 08:59:30 pm
content: YesNEVER put your body in front of the beam. Indirectly heated testicles are one thing but microwave radiation into an eyeball will cook your corneas.

author: sarepairman2
author_rank: Frequent Contributor
timestamp: October 01, 2015, 02:56:20 am
content: is your emplolyer the bad guy from the movie "speed"?imo someone is just fucking with the new guy lol...the boss was out doing blow all night and decided he is gonna get his lawnmower repair business into the RF business lol (after he broke into his old neighbors garage and stole a old CRO)!!i think that tbh the only radar you will be making if your company lab is equipped with a 10MHz oscilloscope and a fluke multi meter is MAYBE a neon bulb RF detector lol..at 77ghz you probobly wont be designing any front ends or antennas.you can detect fairly high frequencies with a common diode, but this is a far far cry from a god damn radar

author: Bud
author_rank: Super Contributor
timestamp: October 01, 2015, 03:46:32 am
content: Quote from: Icarus on September 30, 2015, 04:15:08 pmThis is the most insane request I have ever heard in my life given the available Lab "gear".Do you know your boss background? If he is an rf/microwave engineer perhaps he just wants test you handling a bad assignment to see what you are capable of. If he is not, I wish you luck working for him.May be you could start from examining feasibility of the requirements, in particular if it is possible to achieve the working distance and 2D resolution with a patch antenna at the required working frequency.

author: daqq
author_rank: Super Contributor
timestamp: October 01, 2015, 05:12:17 am
content: QuoteIt's not phased out, it's just obscenely complicated to work with. The reason that there are very few off the shelf solutions for this is that people try to avoid working with this high frequencies, unless it is absolutely necessary, because it is obscenely complicated and pricey. The only mass produced stuff (to the best of my knowledge) that goes above 10 GHz are satellite LNBs and microwave data relays (though those are not particularly high volumes), and miniature Doppler radar modules (http://www.ebay.com/itm/HB100-Microwave-Wireless-Doppler-Radar-Detector-Probe-Sensor-Module-10-525GHz-/201414956704?hash=item2ee54456a0) for motion detection.

author: Psi
author_rank: Super Contributor
timestamp: October 01, 2015, 05:49:55 am
content: it's 50% greybeard and 50% having the expensive test equipment. (if you have to ask how much you cant afford it)You can usually get away without one of those, only Just, but without both you are doomed

author: Icarus
author_rank: Regular Contributor
timestamp: October 01, 2015, 05:58:13 am
content: Quote from: Psi on October 01, 2015, 05:49:55 amNice pep talkand it's awful truth. I've never designed some thing beyond 2GHz, millimeter wave is just uncharted territory for me

author: Psi
author_rank: Super Contributor
timestamp: October 01, 2015, 06:13:49 am
content: Quote from: Icarus on September 30, 2015, 04:15:08 pmYou probably could design it using prebuilt modules for the RF sections.But it would be very expensive, although a lot cheaper than buying the test equipment.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 01, 2015, 06:33:53 am
content: Quote from: Icarus on September 30, 2015, 04:15:08 pm..so how long did it take to stop laughing.....?Your employer is either having a joke, or so hopelessly clueless you probably should look for another job.Did he give you a budget ? How many digits did it have ? If <6, forget it.

author: ConKbot
author_rank: Super Contributor
timestamp: October 01, 2015, 06:11:20 pm
content: Jeeze, and I felt minimally equipped to do a 2 ghz transmitter with a very minimally optioned signal analyzer and a VNA.Order the infineon 24 ghz radar eval kit and drop it off on the software guys desk. Say you'll whack on a lna and PA when the software is working :p

author: AlfBaz
author_rank: Super Contributor
timestamp: October 01, 2015, 06:36:03 pm
content: 77GHz!? Give him a quote for an infrared camera with a telescopic lens capable of seeing 2km away

author: Icarus
author_rank: Regular Contributor
timestamp: October 01, 2015, 06:42:08 pm
content: Hehehehe both are perfect ideas@mikeselectricstuff: He didn't give me any number. However he is trying to reduce cost of a product by "thinning the paint" and "decreasing size of cables" (those are carrying 60 amp)I guess I have to hop another job as soon as I could find.P.S.: Whole thing is just look a like a Dilbert cartoon

author: ehughes
author_rank: Frequent Contributor
timestamp: October 02, 2015, 02:04:12 am
content: Your employer is insane.You will not be able to do it by simulation aloneIf your company only has a meter and scope and no microwave experience, there is no way you will be succussful.Freescale has a 77GHz solution chipset. It is a starting point. From the information you provided, you are on a sinking ship. Get off now. Your employer is nuts and this project will be miserable.

author: ale500
author_rank: Frequent Contributor
timestamp: October 02, 2015, 05:50:07 am
content: Freescale's 77 GHz solution for vehicles needs a team around 100 people: basic software, radar, testers, hw people and one and a half to two years work. And years of planning. and that is for 150 to 200 m... Good luck.

author: katzohki
author_rank: Frequent Contributor
timestamp: October 02, 2015, 05:23:57 pm
content: 2km... I feel like you are going to run into some regulations issues if you manage to pass the hurdles already mentioned. You know, FCC and the like.

author: tszaboo
author_rank: Super Contributor
timestamp: October 02, 2015, 06:11:42 pm
content: There are certain projects/assigments, which you get, where you are supposed to answer in one of the following sentence:"Is this a joke?""I cannot do it.""I'm not comfortable with this, and I'm not willing to do it.""I quit." (this, if they ask you to work on the legacy system)

author: German_EE
author_rank: Super Contributor
timestamp: October 02, 2015, 07:46:46 pm
content: I agree with NANDBlog. I was once told (by the best manager I ever had) that a good engineer knows when to walk away. This is one of those moments.Think if it this way. The wavelength of a 24 GHz signal is 12,5mm so a quarter wave antenna inside a waveguide will be 3,125mm long. The wavelength of a 77 GHz signal is 3,896mm and a quarter wave antenna (is there such a thing?) will be 0,974mm in length. This is insane and I doubt that anybody apart from Shamir at The Signal Path will have any idea how to tackle the job.

author: AF6LJ
author_rank: Unknown
timestamp: October 02, 2015, 07:58:47 pm
content: Quote from: Icarus on October 01, 2015, 05:58:13 amYou have your work cut out for you; I hope you have a passion to learn new stuff, you will be doing a lot of that.And Good for You for taking on such a project, if it turns out your boss can't come to the table with the resources you will come away from this experience all the wiser and all the richer in knowledge.Good Luck.

author: AF6LJ
author_rank: Unknown
timestamp: October 02, 2015, 08:01:39 pm
content: Quote from: AlfBaz on October 01, 2015, 06:36:03 pmThat is a stretch for 77GHZ unless you want to run an insane amount of effective radiated power.

author: German_EE
author_rank: Super Contributor
timestamp: October 02, 2015, 09:02:06 pm
content: The math is far beyond my abilities but I think that you might find the following link of interest:http://scholar.uwindsor.ca/cgi/viewcontent.cgi?article=1127&context=etdRegarding commercial use of this information, please see the bottom of page one.

author: tggzzz
author_rank: Super Contributor
timestamp: October 02, 2015, 09:33:55 pm
content: Quote from: German_EE on October 02, 2015, 07:46:46 pmProfessor Eric Laithwaite of Imperial College used to set final year examps with one question that could be answered by anyone who had attended the lectures and paid attention - it would get you a pass mark. Another question that hadn't been part of the course, but could be answered by someone who understood the course. And yet anothe question that could not be answered adequately during the exam.He expected his students to be able to recognise each question for what it was, and to avoid the last type of question.I doubt you could get away with that nowadays, more's the pity.

author: German_EE
author_rank: Super Contributor
timestamp: October 02, 2015, 09:37:38 pm
content: I remember Professor Laithwaite, there was a TV programme that I used to watch as a child called 'Young Scientist of the Year' and he was on the judging panel. Sadly I suspect that programming like this is no longer shown.

author: tggzzz
author_rank: Super Contributor
timestamp: October 02, 2015, 09:41:10 pm
content: Quote from: German_EE on October 02, 2015, 09:37:38 pmYes, it was a good, inspirational programme. I learned a lot from it.The last time I saw anything remotely similar was in the 80s, "The Great Egg Race" with Prof Heinz Wolff.

author: AF6LJ
author_rank: Unknown
timestamp: October 02, 2015, 09:45:04 pm
content: Quote from: German_EE on October 02, 2015, 09:37:38 pmSad to see stuff like that go away, like the science shows of the sixties here in the US.You could call that "the Americanization of modern culture" and I doubt many here from the US would take issue with it.Popular culture stinks and like junk food has no nutritional value.Popular Culture like a cesspit; it is not something to be immersed in but something to rise above.

author: Icarus
author_rank: Regular Contributor
timestamp: October 03, 2015, 07:20:14 am
content: German_EE, NANDBlog you are right, I'll try to explain the issuseand I'm reading the paper.katzohki: I didn't see that was comingProbably its quite difficult or impossible.

author: tggzzz
author_rank: Super Contributor
timestamp: October 03, 2015, 11:36:56 am
content: Quote from: Icarus on October 01, 2015, 06:42:08 pmI might be that your new boss is setting you a test to see what you can do, can't do, how you find out things, etc etc. If he accepts your reasoned recommendations then that would be reasonable. If he doesn't accept them then another job might be preferable.One of my rules, which I never had to test, was that it is acceptable to leave a new permanent job within a month (something changed between interview and job => abort) or after two years (something accomplished => new challenges elsewhere). Leaving after 6 months requires explanation.