Funny, When I go to these VHF and Above conferences Agilent or Keysight usually have a sales engineer and a pair of 200,000 VNAs there for a weekend... Just for the test range and the noise figure competition. Not exactly amateur, as most of the people who do microwave ham radio > then 10 Ghz do work with microwave design at the day job. Steve
77GHz Radar with FR4 board?
Started by ●April 1, 2019
Reply by ●April 8, 20192019-04-08
Reply by ●April 8, 20192019-04-08
On Mon, 8 Apr 2019 12:52:35 -0700 (PDT), sroberts6328@gmail.com wrote:>Funny, When I go to these VHF and Above conferences Agilent or Keysight usually have a sales engineer and a pair of 200,000 VNAs there for a weekend... Just for the test range and the noise figure competition. > >Not exactly amateur, as most of the people who do microwave ham radio > then 10 Ghz do work with microwave design at the day job. > >SteveIn this thread, we were kicking around ideas for working around the obvious dumb-FR4 losses. Like suspended substrate, FR4-kapton rigid-flex, things like that. Using an expensive laminate was already the not-preferred option. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●April 8, 20192019-04-08
If I really had to could go ultra cheap, vacuum silver metalized / or copper electroplated ABS plastic is very close to the old Rogers Duroid electrically @ 10 Ghz... Duroid 5880 Er @ 50 Ohms stripline, 2.22 +/- 0.02 Dissipation .0009 @ 10 Ghz Plated ABS Er @ 50 Ohms stripline, 1.89 to 2.12 Dissipation .0024 @ 10 Ghz It has about 1.5x the expansion coefficient, around one half the specific gravity, similar mechanical properties under tension/compression but 1/3rd the heat dissipation and one third the maximum usable temperature. Only problem is soldering to it... You would have to wirebond everything and glue the die down. But its good for antennas and cheap waveguides, as is a specialized low loss plastic such as PREPERM... That said, I'd look at ISOLA and the Chinese ISOLA clones. Since LNAs /LNBs sell for next to nothing whatever is used for the LNB is probably the ticket.. This is worth a read for losses due to surface quality, etc.. https://www.isola-group.com/wp-content/uploads/PCB-Material-Selection-for-RF-Microwave-and-Millimeter-wave-Designs-1.pdf There is a very private GHZ and Up RF mailing list I subscribe to, I'll ask what the non ceramic cheap PCB du Jour is... That should settle this.. Steve
Reply by ●April 8, 20192019-04-08
On Tuesday, April 9, 2019 at 3:53:17 AM UTC+10, John Larkin wrote:> On Sun, 07 Apr 2019 00:37:17 -0400, krw@notreal.com wrote: > > >On Thu, 04 Apr 2019 19:58:27 -0700, John Larkin > ><jjlarkin@highlandtechnology.com> wrote: > > > >>On Thu, 4 Apr 2019 19:28:10 -0800, Robert Baer > >><robertbaer@localnet.com> wrote: > >> > >>>John Larkin wrote: > >>>> On Tue, 02 Apr 2019 13:25:51 -0700, Joerg <news@analogconsultants.com> > >>>> wrote: > >>>> > >>>>> On 2019-04-02 12:38, John Larkin wrote: > >>>>>> On Tue, 02 Apr 2019 11:17:15 -0700, Joerg <news@analogconsultants.com> > >>>>>> wrote: > >>>>>> > >>>>>>> On 2019-04-02 10:59, John Larkin wrote: > >>>>> > >>>>> [...] > >>>>> > >>>>> > >>>>>>>> An air cavity hogged out of one internal layer would be interesting. > >>>>>>>> It's not exactly multilayer or suspended substrate: we could invent a > >>>>>>>> new name if there isn't one already. > >>>>>>>> > >>>>>>>> https://www.dropbox.com/s/l8xpzmwsg8lq287/DSC03456.JPG?dl=0 > >>>>>>>> > >>>>>>> > >>>>>>> That looks like an ant hotel :-) > >>>>>> > >>>>>> Maybe the toroid likes fresh air? For 2 pF+4200 volts isolation I'll > >>>>>> tolerate a little quirkiness. > >>>>>> > >>>>> > >>>>> That is pretty good. For most of my apps it would depend on what the > >>>>> spec'd working voltage is. > >>>>> > >>>>> > >>>>>> (I'm prepping for a customer visit. Jerks. Makes me crabby.) > >>>>>> > >>>>> > >>>>> I hope it goes well. So far I have been lucky, only very few customers > >>>>> over my career that I didn't like. > >>>> > >>>> For some reason, people in the semiconductor business are usually > >>>> awful. I think Shockley established the mores of Silicon Valley. > >>>> > >>>> https://en.wikipedia.org/wiki/Shockley_Semiconductor_Laboratory > >>>> > >>>> https://en.wikipedia.org/wiki/Traitorous_eight > >>>> > >>>> > >>>> > >>>> > >>> Shockley did not invent the transistor; it was patented in the early > >>>1930's. > >>> Actually TWO patents, and they were FETs! > >> > >>Bardeen and Brattain discovered the point-contact bipolar transistor. > >>Shockley tried to take credit for it. > >> > >>I had lunch with Brattain when I was a kid. Nice old guy. > > > >My mother knew Bardeen, personally (first name basis). She always > >said that if there are room full of people and you knew he was in the > >room, he would be the last you'd suspect of being a twice Nobel > >laureate. > > Bell Labs was wonderful. Shockley was the rare jerk. > > I have a good book about Bell at home. I'll post the link.Probably "The Idea Factory" by Jon Gertner ISBN 9781-594203282 https://en.wikipedia.org/wiki/The_Idea_Factory> It's been said that all the great discoveries were made by people who > had lunch with Harry Nyquist.Or Claude Shannon. Bell Labs wasn't short of brilliant people. Neither was EMI Central Research or RCA's Sarnoff Lab, though Bell Labs may have had more of them. -- Bill Sloman, Sydney
Reply by ●April 8, 20192019-04-08
On Tuesday, April 9, 2019 at 6:12:30 AM UTC+10, John Larkin wrote:> On Mon, 8 Apr 2019 12:52:35 -0700 (PDT), sroberts6328@gmail.com wrote: > > >Funny, When I go to these VHF and Above conferences Agilent or Keysight usually have a sales engineer and a pair of 200,000 VNAs there for a weekend... Just for the test range and the noise figure competition. > > > >Not exactly amateur, as most of the people who do microwave ham radio > then 10 Ghz do work with microwave design at the day job. > > > >Steve > > In this thread, we were kicking around ideas for working around the > obvious dumb-FR4 losses. Like suspended substrate, FR4-kapton > rigid-flex, things like that. Using an expensive laminate was already > the not-preferred option.Not strictly accurate. Joerg just wanted to know if he could get away with FR4 because it is absolutely the cheapest and easiest option. A more expensive laminate might well be the cheapest option - looking at the problem as a whole - but Joerg doesn't like spending any more than he absolutely has to. -- Bill Sloman, Sydney
Reply by ●April 9, 20192019-04-09
On Mon, 08 Apr 2019 10:53:08 -0700, John Larkin <jjlarkin@highland_snip_technology.com> wrote:>On Sun, 07 Apr 2019 00:37:17 -0400, krw@notreal.com wrote: > >>On Thu, 04 Apr 2019 19:58:27 -0700, John Larkin >><jjlarkin@highlandtechnology.com> wrote: >> >>>On Thu, 4 Apr 2019 19:28:10 -0800, Robert Baer >>><robertbaer@localnet.com> wrote: >>> >>>>John Larkin wrote: >>>>> On Tue, 02 Apr 2019 13:25:51 -0700, Joerg <news@analogconsultants.com> >>>>> wrote: >>>>> >>>>>> On 2019-04-02 12:38, John Larkin wrote: >>>>>>> On Tue, 02 Apr 2019 11:17:15 -0700, Joerg <news@analogconsultants.com> >>>>>>> wrote: >>>>>>> >>>>>>>> On 2019-04-02 10:59, John Larkin wrote: >>>>>> >>>>>> [...] >>>>>> >>>>>> >>>>>>>>> An air cavity hogged out of one internal layer would be interesting. >>>>>>>>> It's not exactly multilayer or suspended substrate: we could invent a >>>>>>>>> new name if there isn't one already. >>>>>>>>> >>>>>>>>> https://www.dropbox.com/s/l8xpzmwsg8lq287/DSC03456.JPG?dl=0 >>>>>>>>> >>>>>>>> >>>>>>>> That looks like an ant hotel :-) >>>>>>> >>>>>>> Maybe the toroid likes fresh air? For 2 pF+4200 volts isolation I'll >>>>>>> tolerate a little quirkiness. >>>>>>> >>>>>> >>>>>> That is pretty good. For most of my apps it would depend on what the >>>>>> spec'd working voltage is. >>>>>> >>>>>> >>>>>>> (I'm prepping for a customer visit. Jerks. Makes me crabby.) >>>>>>> >>>>>> >>>>>> I hope it goes well. So far I have been lucky, only very few customers >>>>>> over my career that I didn't like. >>>>> >>>>> For some reason, people in the semiconductor business are usually >>>>> awful. I think Shockley established the mores of Silicon Valley. >>>>> >>>>> https://en.wikipedia.org/wiki/Shockley_Semiconductor_Laboratory >>>>> >>>>> https://en.wikipedia.org/wiki/Traitorous_eight >>>>> >>>>> >>>>> >>>>> >>>> Shockley did not invent the transistor; it was patented in the early >>>>1930's. >>>> Actually TWO patents, and they were FETs! >>> >>>Bardeen and Brattain discovered the point-contact bipolar transistor. >>>Shockley tried to take credit for it. >>> >>>I had lunch with Brattain when I was a kid. Nice old guy. >> >>My mother knew Bardeen, personally (first name basis). She always >>said that if there are room full of people and you knew he was in the >>room, he would be the last you'd suspect of being a twice Nobel >>laureate. > >Bell Labs was wonderful. Shockley was the rare jerk.She knew him at UIUC but yes, Bell Labs was the incubator for the entire industry.>I have a good book about Bell at home. I'll post the link. > >It's been said that all the great discoveries were made by people who >had lunch with Harry Nyquist.
Reply by ●April 10, 20192019-04-10
The first suggestion to come back for cheap was the Rogers RO4000 series, I'm still waiting for other posts to come down the list. Steve
Reply by ●April 13, 20192019-04-13
sroberts6328@gmail.com wrote:> The first suggestion to come back for cheap was the Rogers RO4000 series, I'm still waiting for other posts to come down the list. > > Steve >Well, I have the Panasonic Megtron 5 which appears to be reasonably competitive and similar. I could e-mail you some datasheets and you could offer a price for a few of the 18x24 sheets. R. Baer --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Reply by ●April 13, 20192019-04-13
Reply by ●April 13, 20192019-04-13
On Sat, 13 Apr 2019 09:01:38 -0700 (PDT), sroberts6328@gmail.com wrote:>Jeorg is the one looking for board, I have enough Duroid for a life time of experiments. > >SteveI used to use duroid for prototypes, before I got good at Dremeling FR4. You can score the duroid with an x-acto knife and then peel up strips of copper. But adhesion is poor, so pads tend to lift. -- John Larkin Highland Technology, Inc lunatic fringe electronics
