PCB Prototype manufacturer ROGERS in China? - Page 1
Forum section: electronics / rf-microwave

author: Yansi
author_rank: Super Contributor
timestamp: June 03, 2018, 02:43:56 pm
content: Hello!the more I am interested in the microwave bands, the more I find need for something better behaved than FR4, especially when attempting to construct microstrip filters (I find it almost impossible to do on FR4).Do you have any experience with prototyping PCB manufacturing in China on Rogers substrates? A quick google search shows that such PCB prototype houses in China exist, but usually they offer this on special request and I am quite afraid of the pricing there.But still not as afraid of the pricing, as what the local manufacturers in Europe want for that. I would describe that as utter nonsense and ripoff, with regards what the substrate really costs and that very likely they do not need to change almost anything in the technology setup I guess. *Do you have any recommendations for any specific manufacturers? What to look for, what to be aware of?I will not need to manufacture any special PCBs, likely simple 2 layer stuff below 5 GHz. What substrate is the cheapest choice for this? I guess the most common two are RO4003C and RO4350B, while the 4003C being the widely used cheaper option. (is it correct?)Thank you for suggestions,Y.//EDIT: * yes. Straight from the RO4000 brochure :RO4000 series laminates can easily be fabricated into printed circuit boards using standard FR-4 circuit board processing techniques. Unlike PTFE based high performance materials, RO4000 series laminates do not require specialized via preparation processes such as sodium etch. This material is a rigid, thermoset laminate that is capable of being processed by automated handling systems and scrubbing equipment used for copper surface preparation.

author: WPXS472
author_rank: Regular Contributor
timestamp: June 03, 2018, 03:34:46 pm
content: I don't have any experience with Chinese suppliers and Rogers substrates. Sorry. But I do have experience with Chinese PCB suppliers and FR4. First, FR4, though good for a lot of things, is awful for RF. It doesn't even have to be microwave either. At my for employer, we were dealing with the Chinese branch of a major American company trying to get some products on their approved vendor list. They didn't like out test fixture at all and provided their own. Though I had some problems with how it was constructed, it did have excellent return loss. They provided the Gerbers for it and we had some made by our Chinese supplier. Even though they physically looked identical, the return loss was simply terrible. This was only up to 1.25 GHz too. We used a Chinese supplier almost exclusively, much to my dismay. They were difficult to deal with from an engineering perspective. Whenever we would send a set of Gerbers and the specs for the materials and panels, they would always send a big list of questions that had to be answered. Sometimes, it was next to impossible to even understand what they were asking. I don't know if they were using translation software, or they just didn't do well with English. One habit they had that I found particularly troublesome, though I admit others might not find it a problem, was that I always sent all dimensions in Imperial measurement format. I think in inches, not centimeters. They would always convert every measurement to metric form when replying. Just out of stubbornness, I would always convert everything back to imperial when I made my replies. If I could have had my way, I would have told them that as the customer, I demanded that they use my measurement system if they wanted to continue to do business. Even though wanted every aspect and detail documented, they had a habit of just changing things without telling us. My advice when dealing with a Chinese supplier is to be up front about what is important to you, provide every detail imaginable, and just let them know that if they want your business, they have to meet your expectations. If you specify something like Rogers material, expect to pay a heavy premium for it because it likely won't be locally produced. The idea that everything that comes from China is junk, is no longer valid. A lot of Chinese companies can do excellent work.

author: rx8pilot
author_rank: Super Contributor
timestamp: June 03, 2018, 04:47:49 pm
content: Subscribing to the thread.Short and misplld from my mobile......

author: yl3akb
author_rank: Regular Contributor
timestamp: June 03, 2018, 06:30:17 pm
content: Interesting topic, I also would like to learn more about low cost options.https://www.pcbcart.com/recently quoted me total of 154$ for 32 (minumum order, I guess) 35x55mm boards with RO4350, but I did not try it (yet).

author: xaxaxa
author_rank: Regular Contributor
timestamp: June 04, 2018, 04:12:39 am
content: The problems with return loss aren't because of FR4, it's because you kept the geometry the same and switched to a material with a different dielectric constant. All microstrip widths must be recalculated for the new substrate material. Also most major pcb fabs in china support impedance control nowadays (often at no extra cost) so you should be able to get return loss better than 20dB up to many GHz.FR4 is perfectly usable for RF up to 6GHz if you design with the losses in mind and use impedance control. There is very little reason to use a more exotic material other than for e.g. microstrip filters; power amplifiers (>20W @ >1GHz).

author: Yansi
author_rank: Super Contributor
timestamp: June 04, 2018, 02:13:50 pm
content: Well.. as the original question didn't get much attention... I have another question:What is the most common rogers material used for RF designs? As I mentioned above, I think that RO4003C and 4530B are the two most common. Not sure which one is the cheaper or more common one.But I have a different interesting question: What is the common substrate thickness used for the designs? I think that for most applications, where microstrip filters are typically required, you can not get away with 1.5mm substrate easily (everything 50ohm will become just insanely! wide - 3.6mm to obtain 50ohm at 3GHz on RO4003C) and thinner must be used, like 0.8 or 0.6mm substrate.Do you have any idea?//One of the local EU manufacturers just replied and in short told me to fuck off, that they won't order any 0.8 rogers for me. Is this normal? I am pissed...

author: ThomasDK
author_rank: Regular Contributor
timestamp: June 04, 2018, 05:20:05 pm
content: These guys do 0.5mm RO4003 in the EU at pretty reasonable prices:https://www.micron20.com/orders/calculator-production?lang=enI haven't tried them myself yet.

author: Yansi
author_rank: Super Contributor
timestamp: June 04, 2018, 05:39:47 pm
content: QuoteFuk em in the ass!!! Had to launch a TOR browser.Was about €200 for 5 pieces of 120x65mm 0.5mm thick RO4003C. Which is quite meh... 40€ for such small board, stupid simple 2 layer stuff, I don't know. Maybe my expectations are a bit different than reality.But it is in EU, which is good to start with. One do not want to pay stupid import duties and the pelf for the shipping company.But thanks for mentioning them. Mayyyyybe I will try, if I do not find a different cheaper vendor.//I have just converted €200 to our currency. I knew 200€ is a lot, but did not expect that especially that much.

author: KJDS
author_rank: Super Contributor
timestamp: June 04, 2018, 07:37:40 pm
content: It's been a while since I ordered any, but I think that 4350 is about £100 for a single 18" x 12" sheet of plain material. 4003C is a lot more, or it might be the other way round.I've generally gone down the route of using expensive but trustworthy board houses, as delaying a project by a month due to a crap board spin costs way way more than even a very expensive board.

author: G0HZU
author_rank: Super Contributor
timestamp: June 05, 2018, 12:50:10 am
content: QuoteI've been using Rogers materials for over 25 years at work for RF design so I can offer a few clues.The most common thickness at work is 0.020" and this is for designs up to maybe 7GHz or so. This gives a (50R) microstrip width that mates fairly well with SMD parts and it means that vias have low inductance.But the price for this is higher dB/inch loss and also this skinny material is very brittle. Very easy to snap a 0.020" thick 4003C PCB like a dry biscuit! Also, the material is quite bendy so it is very easy to crack MLCC caps on a PCB like this unless you stiffen it up with some backing material before you solder parts to it. A typical design at work would have an 8-12 layer FR4 core with 0.020" Rogers layers as the top and bottom layers. This complex multilayer stack helps with rigidity and makes for a very versatile PCB with loads of options for signal/control and power planes etc. But it is very expensive!We are slowly phasing out the use of 4003C in favour of 4350B and I think this is because of reasons to do with ROHS. But for general purpose RF design/dev work you would be best to choose whichever you can find cheapest as the RF performance is very similar.At work we have always used a PCB mill to make rapid PCB prototypes with Rogers materials of various thickness. The most common are 0.060", 0.032" 0.030" or 0.020" but as I said earlier, we tend to go for 0.020" nearly all the time now. At some point it may be that we use 0.010" more often.I do quite a bit of work here at home with Rogers material and I also have a PCB mill (T-Tech 7000S series) and I bought this machine as an old/used trade in about 16-17 years ago for about £800.I think part of the reason it costs a lot to have a Rogers PCB made is that it is assumed that the PCB etching tolerance and the other PCB manufacturing tolerances need to be very tight. For this reason, we tend to use the top PCB companies like Graphic, Exception or Labtech here in the UK to make our 'real' PCBs that use Rogers material and the costs are very high even for prototypes because of the need for repeatable etching accuracy. Otherwise, what's the point in trying to make a high performance RF filter or coupler with expensive materials if the etching tolerance will spoil the results?Have you considered buying bare material and etching it yourself? Maybe practise on FR4 until you can get good results with accurate etching?

author: Yansi
author_rank: Super Contributor
timestamp: June 05, 2018, 08:22:46 am
content: Quote from: KJDS on June 04, 2018, 07:37:40 pmYour price are a bit high. RO4003C is about $100 (not GBP100) for that kind of size, RO4530B is about half that. I have only briefly looked through RFMW stock. I do not know where else I could buy these.I am not afraid of the Chinese guys screwing up, they actually never did any of my PCBs. But the expensive local mfgs, yes they screwed a lot. Hair, someone's oily finger in a soldermask, inconsistent solder mask color, ENIG board that had a leakage due to gold depositing in a microfilm all over the board, not abiding to the extra cost express manufacturing deadlines, and such. The chinese guys can screw you in many different ways, but from my experience the failure rate there is much lower actually. But I am only mainly a hobbyist, so I do not spin off that much PCBs.G0ZHU: 20mil substrate seems too thin, I understand it may be very fragile. I'd rather use something in the range of 0.5 to 0.8mm, for example the 30mil or 20mil RO4530B substrate, as it gives reasonable 50ohm trace width I am used to.I do not have PCB mill, my friend does, but I would not trust that for precision. And it is tiringly slow. But I have no issues whatsovever etching my our PCBs using the photographic method, with as good precision as it can get at home. (600DPI laser printer) Can do both positive and negative solder resist film.Problem is, where to obtain (in EU) the substrate. I only mainly find RT/duroid material, which I know nothing about. Only that HAMs used that a lot in the past, as there wasn't anything much different available, apart from plain very thin PTFE laminates, which are pain in the butt to work with. Do you have any ideas, where to buy some in the EU, especially RO4530B substrate in about a the 0.5 to 0.8mm thickness range, without the cost being stupidly excessive due to "exclusivity" of the goods?However doing such RF PCBs at home has major drawbacks and that is no plated vias. I am used to work with small SMT stuff, including fine pitch QFN (which most RF/uW chips are these days in anyway), where it is mandatory to use small vias and vias under the devices itself (exposed pad GNDs and such). Hence looking for a cheap manufacturer, that can do the 4530B or 4003C. (Guessing, the 4530B should really be the cheaper and suitable option for a home-gamer. Still huge leap better than FR4!)I do not think the price is high due to increased precision expectancy, for example in the Bulgarian manufacturer, one can clearly specify the precision, yet the price is a nonsense. The high price is I think mainly due to exclusivity. The vendors think, they can just simply rip off people, as corporates almost don't give a sh!t about the price (they just want the work done) and home-gamers are only a small if not almost zero fraction of the customer base for such special materials.//EDIT: Even one of the chinese guys I have asked for 4003C gave estimate $300 for a small, 45x30mm pcb x 5pcs, with almost no drilling, no solder mask and silk, ENIG. I was like WTF?!

author: G0HZU
author_rank: Super Contributor
timestamp: June 05, 2018, 09:18:27 pm
content: QuoteIt's possible to buy rivet kits (eg from LPKF) for the PCB vias and this is what we do at work for our milled boards. When fitted correctly they do look like plated holes. The rivets come in various sizes. However, it really is a labour of love to fit them to a board and it requires some skill and experience to do it quickly and reliably. Otherwise it can become a frustratingly long and clumsy experience. Even then they need to be soldered to make sure they are reliable.One thing to watch out for is that the ENIG finish can wreck the insertion loss of coupled line filters up in the GHz region, especially combline or interdigital designs. I've been there and made this mistake many years ago.The nice thing about the Rogers 4xxx material is that it is repeatable and the dielectric constant is well documented for the various PCB thicknesses and metal weight/roughness. It's also quite good in terms of how little the dielectric constant changes in the xyz axis. So it usually gives rewarding results if you first simulate with something like Sonnet (Lite) and then make a PCB.However, if you just want to mess about with a few designs to gain experience then maybe try a cheaper substrate. Even FR4 can provide a useful learning experience even though the dielectric constant will be poorly controlled. Many years ago GIL GML1000 (0.030") was a really good choice as it was cheap and reliable. But it went obsolete. However, it might be worth asking if you can buy old stock of it from a PCB house. Some of them still have it. I still have loads of sheets of it here and it is really easy to mill and doesn't wear the tools out as quickly as FR4 or (even worse) Rogers 4003 or 4350. The Rogers material wears the milling tools even more than FR4!

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: June 06, 2018, 05:44:25 am
content: Quote from: G0HZU on June 05, 2018, 09:18:27 pmWhat's the reason for this? I've seen recommendations to not use ENIG for RF boards on some app notes, but without an explanation.The OP might be able to buy substrates at this Italian site:https://www.rf-microwave.com/en/rf-microwave-laminates/371/You may also be able to find cheaper quotes from board houses if you specify non-Rogers RF materials.

author: G0HZU
author_rank: Super Contributor
timestamp: June 06, 2018, 11:33:31 pm
content: I don't know a definite answer but I think it's because of the nickel content. Nickel has a relatively high permeability compared to copper and the conductivity is less. How much it affects the insertion loss probably depends a lot on the substrate thickness and therefore how significant metal losses are for a given microstrip line and how the microstrip is employed (eg in a coupled line filter).I got stung by this when I swapped across to ENIG for an RF preselector board many years ago. This typically had a suite of printed combline filters across 500MHz to a couple of GHz or so. Each section had a five finger combline followed by an LNA followed by another combline filter. The overall loss was something like 2dB worse with ENIG but I can't remember for sure. This was way back in the 1990s. But all the boards failed the test spec.It was possible to slowly rub away the ENIG coating with a fibre pen and watch the insertion loss slowly recover to what it should have been. I've tried to avoid ENIG on printed filters ever since. Maybe the process is better now but I think this is a fairly well known issue with ENIG even today.

author: Yansi
author_rank: Super Contributor
timestamp: June 07, 2018, 10:45:41 am
content: I have found this interesting to read, regarding the ENIG insertion loss problem. However they stay there is negligible effect on a filter, compared to for example a solder mask covering. (which I think is sort of expected)? However I am not sure what surface to use then. Bare copper? That sucks (oxidizes). HASL? I don't think the rough surface finish will be good for it. So I might just stick with the ENIG. The insertion loss is not that much different, according to the application note. Certainly good enough for me.https://www.rogerscorp.com/documents/2341/acm/articles/Ambiguous-Influences-Affecting-Insertion-Loss-of-Microwave-Printed-Circuit-Boards.pdfTo sum up this thread: There are not much options for Rogers from china, if any at all. There is also not many options, even sourcing rogers PCBs within Europe. Third of the companies don't give a fuck about your single PCB, third quote rip-off prices (because they outsource it, seems the same for the chinese) and third is about usable. But still the price is driven insanely high because of fees like "technology preparation", which are some type of fixed fee (usually charged even for FR4 PCBs). Arrrgh!I was quoted this (so far the best quote, apart from the "technology preparation") from a Czech company Pragoboard.cz (they seem to have many kinds of Rogers substrates in stock ready) for board like this:100x100mm, 2L PTH Rogers RO4350B 0.762mm, 18um Cu, >0.3mm drill, >150um trace/space, 2x green soldermask, 1x white silk, HASL or ENIG (+$1/dm^2):1pcs $79/pc, 3pcs 28$/pc, 5pcs $19/pc, 8pcs $16/pc.Technology preparation: $72Lead time: 10 working days.(Pricing without VAT).Not cheap, I can tell you that, but at least they have a stock of the material. What SUCKS is that they want a minimum 6dm^2 minimum order. Bastards!!That is fucking to much for just a filter to be tested here and there.I will probably create a different thread, about the microstrip filter design. I have experimented a bit with it, never got any useful results out of it. Don't know how to do it correctly.

author: WPXS472
author_rank: Regular Contributor
timestamp: June 09, 2018, 06:59:28 pm
content: Quote: The problems with return loss aren't because of FR4, it's because you kept the geometry the same and switched to a material with a different dielectric constant. All microstrip widths must be recalculated for the new substrate material. Also most major pcb fabs in china support impedance control nowadays (often at no extra cost) so you should be able to get return loss better than 20dB up to many GHz.Our problems with FR4 weren't because we changed substrate materials, it was because the FR4 from different board houses was sourced from different manufacturers and had different characteristics, even though you couldn't tell the difference by looking at them. We also made some parts using printed, inductors and they varied from time to time. The particular I mentioned seemed to have 50 dB return loss at 1.25 GHz. I say seemed to because I didn't trust either the calibration nor the VNA we were using to be that accurate. Our boards were only about 22 dB at 1.25 GHz. I have personally never used FR4 above 1.25 GHz because we didn't make parts that went any higher. I wasn't too crazy about the performance of FR4 even at 1.25 GHz. The fellow who replaced me says he is investigating alternate board materials. I wish him luck in getting away from FR4. Those particular parts are very cost sensitive.

author: Yansi
author_rank: Super Contributor
timestamp: June 09, 2018, 07:14:32 pm
content: There is a quite common material "FR408" which is supposed to be better behaved at the higher end.//Well I have just looked, the DK of the FR408 seems to be pretty well controlled, about 3.66 - same as the RO4350B, huh?Y.

author: eb4fbz
author_rank: Regular Contributor
timestamp: June 09, 2018, 08:24:19 pm
content: PCBCart has RO4350B, i have used them a couple of times.

author: Yansi
author_rank: Super Contributor
timestamp: October 11, 2018, 08:34:58 pm
content: Quote from: eb4fbz on June 09, 2018, 08:24:19 pmThank you for suggesting them. Could you provide more info about the size of boards, substrate thickness and the resulting price please?The question of where to manufacture any kind of Rogers PCB prototypes is still open. It seem that most (if not all) manufacturers have the pricing set ill and only for corporates. Which is not unexpected, but makes microwave/RF hobby a bit tough, when one wants to do something more serious, than a HF transceiver from a kit.Y.

author: eb4fbz
author_rank: Regular Contributor
timestamp: October 12, 2018, 07:24:12 pm
content: 30x25mm individual boards:30mil RO4350 (0.762mm)0.5oz (18um) copperNo soldermask, no silkscreenPCB Cart:Tooling cost: 40€Unit price: 0.7€/pcs for 100 units

author: Yansi
author_rank: Super Contributor
timestamp: October 13, 2018, 09:05:02 pm
content: Thanks for sharing. However I am a bit afraid that my opposite requirements (larger board, less pieces) will invoke some nasty price.However I find those 40€ still way better than anything I have found so far. As soon as I will have something finished, I will try asking for a price.Y.

author: rx8pilot
author_rank: Super Contributor
timestamp: October 13, 2018, 09:24:27 pm
content: Quote from: eb4fbz on October 12, 2018, 07:24:12 pmI just submitted a quote to PCB Cart for a Rogers design. 3 days to see what they say.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 14, 2018, 12:08:43 am
content: https://www.matrixelectronics.com/products/panasonic/megtron-7/

author: vk6zgo
author_rank: Super Contributor
timestamp: October 14, 2018, 02:08:29 am
content: Quote from: WPXS472 on June 03, 2018, 03:34:46 pmGee! I'll have to tell NEC, Harris, Thomson, etc, that they have been doing it wrong for the past forty plus years!QuoteWe had a bunch of amplifier modules which were supposedly built on Rogers material.One, maybe the prototype, was probably the real thing, but all the others were on some stuff which looked the same, but after a few times when the LDMOS devices "cooked up", (another story*), started to come apart.FR4 would have been a lot better!*These amps were 300watt units, combined to make 600watts, then further combined to ultimately make 1.2 kW.The problem was that the Chinese manufacturer didn't individually tune the amp modules, so they would cook the unbalance loads, in turn, unbalance load would cook on the next combination down, & so on.These were UHF amplifiers.

author: IconicPCB
author_rank: Super Contributor
timestamp: October 14, 2018, 06:16:00 am
content: I have had some experience with rogers 4xxx materials fabricating cavity structures.not purchasing finished boards, actually fabricating them myself.Structuring copper and laminating /pressing multi layer structures in my shop.There are a couple of things to observe when working in the 5 Ghz region.Surf ace structure will affect the return loss. It will send the group delay crazy if surface is not maintained in untouched un scoured condition.It is a difficult material to laminate despite claims that it can be processed with fr4 like process parameters.Having addressed technical issues let me address commercial realities by saying:"... Sell on price, live on rice..."Yansi... i am not surprised You were told off... It takes time and effort and additional process capabilities to handle Rogers and squeeze every little dB out of the materials in order to meet design objectives.Just keep in the back of your mind... quality is like oats... once they have been through a horse... they cost a little bit less.

author: Yansi
author_rank: Super Contributor
timestamp: October 15, 2018, 08:42:52 am
content: Quote from: IconicPCB on October 14, 2018, 06:16:00 amWhy should I? I know that as a hobbyist every single company thinks I should f.ck off when requesting special technology. Prices of these are set only for corporates, that just don't care and pay whatever number is present on the bill.As I like to play with microwave tech, you know, some circuits do not work well with FR4, hence the requirement for better substrate.But at least am trying to find the cheapest manufacturer. So far PCBCart looks promissing. A few days ago, I got a quote from RayPCB. They ask $230 for a 3pcs 100x100mm (2ly 20 or 30mil 4350B). That is just no! I can get this about same same price from an (otherwise very expensive) local company too.What the hell I am telling myself. I think the cost of the substrate is about 4-6€ per square decimeter. Why the PCBs are so f*ing expensive?

author: IconicPCB
author_rank: Super Contributor
timestamp: October 15, 2018, 09:09:15 am
content: Yansi,At the risk of keeping a civil tongue...Just ask Yourself how much the local Mechanic charges to do routine oil change and maintenance on a car.Then think about how much it costs to live in the economy You are immersed in and how much an hour of Your labor will earn You.Then think about how much it actually costs the company which provides You with the hour of labor oportunity.And dont forget the company is there to turn a buck for the share holders.And now settle on a ratio between the company hourly charge out rate and Your income hourly rate.I am sure You do not whinge paying for Your beer. May be You should go and brew Your own?OH and do use quality oats.

author: Yansi
author_rank: Super Contributor
timestamp: October 15, 2018, 09:42:35 am
content: While keeping the civil language: Sorry, I do not drink beer. And do not steal. Though the simple prototype will cost me a bit more than half my monthly earning. Do you roger that or do you volunteer to sponsor me?Maybe $200 is not a lot for a westerner or Aussie like you, but for me, it is hell of a lot.

author: xaxaxa
author_rank: Regular Contributor
timestamp: October 15, 2018, 06:00:32 pm
content: in that case I think your best two options are:1. figure out a way to make do with FR4; don't believe anyone who tells you FR4 is no good for RF (<5GHz). I have built everything from 2.4GHz low noise amplifiers + filters to 5.8GHz power amplifiers on FR4 (and the losses were negligible if you design it properly). My company's first commercial product which is a 3GHz vector network analyzer was done entirely on FR4.2. etch the PCBs yourselfIf your filters performed badly on FR4 it has a high chance of performing badly on rogers material too. If you look at the datasheets the difference in loss between the materials isn't THAT big, and plus a big part of your loss is the copper losses which will be the same for any material (but will be different depending on the trace width for a given impedance).

author: pzw
author_rank: Newbie
timestamp: March 22, 2019, 02:54:28 am
content: I know it is an old thread, but maybe you are still looking...I just came across PCBWay, and they do offer Rogers 4003C and 4350B laminates for prototyping. For 10x 100x100mm PCB they charge $97 without shipping... I think that is a very reasonable price. Lead time is 7 - 8 days, I guess business days :-) ...Please let us know what the experience is if you decide to use them..!ThanksPaul

author: piranha32
author_rank: Unknown
timestamp: March 22, 2019, 03:02:32 am
content: Quote from: pzw on March 22, 2019, 02:54:28 amI found this company through my twitter feed:https://micron20.com/According to their calculator one 100x100mm board on 0.8mm 4003C costs 39.39E (13.00E setup + 26.39E for 1 board) plus shipping.

author: dcarr
author_rank: Regular Contributor
timestamp: March 22, 2019, 03:51:18 am
content: Two ideas:1. OSHPark 4 layer process uses Isola FR408 - $10/sq in, empirically about 2x better than FR4 by my measurements at 10GHz, etching tolerance is "adequate", does have ENIG finish2. PCBPool in Europe offered (may still) a RF PCB service that I remember being reasonably pricedWould be nice to find a good cheap option for this.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: June 11, 2019, 01:51:00 pm
content: Quote from: blueskull on March 22, 2019, 04:25:33 amYou would be surprised as to how anisotropic even rogers material still is. This is also why modern rogers datasheets list 2 permittivities: one measured by some IPC standard, and one to use in a design, because the IPC standard does not match practical circumstances. To give you an idea about the error: iic, Ultralam 3850 has a IPC DK of 2.9, and a actual DK for PCB structures of 3.15.

author: Fabian
author_rank: Contributor
timestamp: June 12, 2019, 01:20:04 pm
content: Two things that might be helpfull for someone:1) Here are a few prices I collected over the past three years or so. Each for signle quantity of a 12"x18" sheet:RO4350B, 6.6 mil: 24€RO4350B: 60 mil: 130€RO4003C, 8 mil: 50€RO4003C, 12 mil: 53€RO3003: 60 mil: 225€RT5880, 10 mil: 220€RT5880, 62 mil: 430€2) There was the discussion why this stuff is "so expensive" even for a small board. You may also take into account that this is quite special stuff and the manufacturer will probably have to do a special run just for you. So he will use a full panel, no matter how large your PCB is. You have to pay for thatHas anyone had experiences withhttps://micron20.com/? They are very cheap (at least I think so... I just got an offer from a different manufacturer for a four layer PCB, 150x150mm, RO4350 on the outside, 1.3mm FR4 in the center: 900€)

author: Georg - PY5ZSE
author_rank: Contributor
timestamp: January 26, 2020, 03:41:19 pm
content: I am bumping this old thread because it's a topic I have been thinking about for quite some time...To understand why Rogers PCB (or Taconic, or whatever RF materials) are so expensive compared with today's chinese FR4 boards one should see why the latter have become so dead cheap:- Pooling. With the hundreds of Gerbers coming in each day, they can fill up their production panels. They might achieve an efficiency (surface turned into Boards / panel area) of 80% or more.- big panels (24 * 36" or more), state of the art equipment, standardized, high yield process.- very high degree of automatization.- running several identical panels that are drilled together (drilling is the most time consuming production step)- material itself is cheap.In comparison, "special" boards, which includes RF Materials:- no pooling. They run a small panel with just one customer's design. Efficiency may be 30%, i.e. 70% of the expensive material ends up in the trash, and production costs have to be paid by the remaining 30%.- small panels (12 * 18"), 1/4 of the "big" FR4 panels. They are either run through a special, smaller prototyping line, or with an adaptor frame through the big one, where they occupy the same space/time slot as a large FR4 panel.- one panel instead of 3 in the drilling machine. even more expensive machine time per board.- the material itself is more expensive, but that, IMHO, explains only a small part of the higher price.The key factor for cheap prototype PCB's is pooling. That only works, if the manufacturer collects enough orders to fill up a panel during his guaranteed turnaround time (- the one day really needed for production). So, quick and cheap are mutual exclusive. On the other side, this opens a possible way to reasonably priced RF boards:- EITHER convince one of the chinese manufacturers that there is a market for an RF PCB pool, offering only selected materials / thicknesses, and accepting significantly longer turnaround times than with standard FR4- OR convince somebody like Aisler, who's business model is pooling and having the panels manufactured by third parties, of the same thing- OR somebody sets up such a pooling serviceThe main question is, which turnaround time will be accepted. A hobbyist will probably have no problem waiting 4 weeks if he gets his little Rogers board for 20 $ instead of 200. For a business, that may be 3 1/2 weeks too long.

author: OwO
author_rank: Super Contributor
timestamp: January 28, 2020, 05:37:22 am
content: Another point is that business customers will usually want 4+ layer boards. Rogers material for RF is really overrated. I've done 5.8GHz power amplifiers on FR4 without a noticeable efficiency drop. One thing I'm *not* willing to do is go back to 2 layer boards. The applications in which using Rogers material is necessary are all very niche (no, you do not *need* interdigital filters at frequencies < 6GHz). Unless it becomes very cheap (no more than 50% more expensive than FR4) for 4 layers I can't see myself using the service. I would rather design my way around it.

author: Yansi
author_rank: Super Contributor
timestamp: January 28, 2020, 09:38:46 am
content: You do not need custom microstrip filters, sure, if you use just the damn standard ISM bands like 2.4G or 5.8G, where filters are available readily made as SMD parts (with mostly poor performance and extreme pricing otherwise).If I want to do a custom whatever outside of the ISM bands, then neither do I have any monolithic filters available, nor any single-chip fully integrated solutions for anything.Microstrip filters on FR4 almost can not be done (silly me have tried), unless running through handful of prototypes and even then it will have less than poor repeatability. Better defined FR4 substrates such as Isola FR408 are not widely available as one would like and expect, so no go that way either.Also, impedance matching of custom discrete LNAs (not integrated "LNA") is almost impossible. You just make oscillators, not amplifiers. They can be tuned, sure, but also you will run through lots of test boards yet the performance will not be really repeatable.And don't forget, that some of us also want some power amplifiers (not just "power amplifiers"), I mean 50W on 3.4GHz. Lossy FR4 would almost melt.

author: Georg - PY5ZSE
author_rank: Contributor
timestamp: January 28, 2020, 03:47:19 pm
content: @Yansi:I basically agree with you. The other point is, that for hobby (ham radio) applications, I don't want to "design around". That's why I am looking for reasonably priced Rogers boards.Where OwO certainly has a good point is the multilayer issue. a commercial product will in most cases have a "small" RF / microwave part and a lot of digital / general electronics around it. In a hobby project I just split that into a RF module and a digital one, and don't care about spending 10$ for cables and connectors.Besides hobbyists and industries that either produce dead-cheap consumer stuff or, like aerospace and mil, don't care about money, there are others: university and research labs, companies that produce very specialized stuff in small quantities. The question is, is there a market for such a project or not. It's certtainly not the manufactureres of garage door remote controls. or 24 GHz doppler motion sensors (where I have seen RF boards for the patch antennas, and they are a consumer product)

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: January 29, 2020, 09:53:33 am
content: Quote from: ghieber on January 26, 2020, 03:41:19 pmI think you forgot a very important reason: Some substrate materials such as the PTFE-based stuff from rogers, to my knowledge, requires a fundamentally different process. You can't just swap out the FR4 panel with a rogers panel (be it with or without a frame to compensate for different panel size) and go with it. This means that whoever does this cannot use their automated line unless they have something set up specifically for a certain rogers family.Quote from: ghieber on January 28, 2020, 03:47:19 pmI work with this kind of stuff in a university/research context, and honestly, there is little demand (at least from my research group) for lower cost. Main push is higher quality and repeatability, since our experience with many manufacturers with RF proto techs is that the repeatability is low: One week you get slightly over-etched, next week you get slightly under-etched, ...And we want better features - when you are trying to demonstrate a fundamental concept, you don't want to be performance limited because your vias had to be 200 um apart etc...

author: IconicPCB
author_rank: Super Contributor
timestamp: January 29, 2020, 10:30:05 am
content: I have manufactured some 3D cavity structures in rogers material.Pressed the multi layer layup, activated and plated the structure only to find the layers did not bond well enough despite following instructions.When asking the client if it were OK to roughen the copper surfaces i was told it is a no no.Apparently there is more to achieving the requisite bond quality to eliminate possibility of plating electrolyte ingress in between the layers.Let me just finish with... if you cant afford it..you don't need it.

author: Georg - PY5ZSE
author_rank: Contributor
timestamp: January 31, 2020, 09:59:24 pm
content: QuoteThe problem with teflon based materials is that nothing sticks to it - neither steaks nor copper. For that reason the holes need an "activation step" for which to my knowledge there are 2 possible procedures, plasma etching and chemical with some solution containing metallic sodium. This is absolutely non - standard, completely different chemistry than the usual one in PCB manufacturing.The "industrial grade" Rogers materials (series 3000 and 4000), however are designed to be treated in the same process as FR4.QuoteNobody "needs" to do electronics as a hobby. But if you do anyway, aint it legitime to try to source your materials at affordable costs?

author: IconicPCB
author_rank: Super Contributor
timestamp: February 01, 2020, 02:33:16 am
content: Ghieber,Ofcourse it is valid to go shopping for an affordable solution and yet in the final analysis if you cant find an affordable solution... thats too bad.You cant go about demanding it.Just so that you understand the other side of this comment...Sell on priceLive on riceDoes Your supplier not deserve a decent living also... after all your "need" is only a hobby not a daily existence.

author: Yansi
author_rank: Super Contributor
timestamp: February 01, 2020, 10:38:12 am
content: They get likely beyond decent living, from the pricing that is often pushed for those "industrial grade Rogers substrates", that likely? can be treated by standard FR4 process, as even the manufacturer of the substrates is boasting in their papers with.That is my point. I am not demanding any special substrates for 100GHz, I am not even demanding any special technology (blind or burried vias in weird custom stackups), I am not demanding any special manufacturing tolerances for etching or stuff.So why the hell do I have to pay even up to $500 premium for a simple, small, 2 layer rogers job for a two transistor LNA and filter for a couple GHz?If anyone can suggest an alternative substrate for RF work, I will happily ditch Rogers and will go with something else.But never mind, I have already given up demanding reasonable. Easiest and pretty affordable solution is to just buy the raw substrate that ain't any expensive and etch it at home, then find an acceptable way for making the vias, such as soldering a piece of wire in here there - such as was done by microwave oriented radio-amateurs 30 freaking years ago, when the RT duroid and similar materials became available behind the iron curtain. So pretty disappointed no progress in this area since back then.

author: IconicPCB
author_rank: Super Contributor
timestamp: February 01, 2020, 10:51:59 am
content: if you are going to etch it yourself and activate the holes...look into soviet era hole wall activation process based on copper phosphite pyrolysis chemistry.It should offer you a good outcome.

author: IconicPCB
author_rank: Super Contributor
timestamp: February 01, 2020, 04:38:50 pm
content: Surface roughness ( pumice slurry ) treatment of FR4 is the classic method of improving multilayer adhesion in a multilayer process.This option is not available in a GHz filter design.Additional chemistry must be deployed to improve on adhesion without deforming surface texture.To quote my old lecturer: everything must be just so,,, anything more or anything less is from the devil...

author: intmpe
author_rank: Contributor
timestamp: May 09, 2020, 03:31:06 pm
content: OK.. Ive been doing sub 5GHz for years using Chinese FR4 PCB vendors - low cost ones.Sorry there is a lot of inexperience here - if you haven't been doing this for 10 years you are still learning - sorry to be frank that's the way it is plus you need some decent qualifications.Firstly, you get 5G NR cell phones out completely on FR4 - and multilayer at that for a few primary reasons:a). No distributed solutions are allowed. If you want distributed circuits its a teflon based material. You can probably get 4350 in China but traditional you could not. Arlon TC was the alternative because its made there. There were export restrictions on the better rogers materials. This has changed but the way China works you would not know if they substitute a local 4350 equivalent anyway. ALWAYS ALWAYS do a test board breakoff on any rogers or fr4 prototype so you can test dielectric constant and loss.b). Because no distributed solutions are allowed you need to make sure your lumped circuits are on point - no weird impedance transformations. With the Q's available on small parts you just cant do it and get decent results. Don't go too small - you wind down your vendor choice and your Q's will suck and so will your design. Do tricks like edge mounting of caps if necessary.c). You can't define a prepeg - they wont use it on FR4. They will use whatever the hell glue they use - it doesn't matter if you define the thickness - be careful with that if you are doing a high density multilayer board make sure your RF layer is thick enough so that the glue layer is not going to kill you as it varies. Thickness is usually not a big player unless you have chosen a very thin rf layer - I've seen that happen due to inexperience and its a show stopper. Think about the thicknesses for the RF and make sure the unknown glue layer is small. Forget about impedance controlled boards. They say they can do it but its hit and miss and not tested at RF.d). Dielectric constants are not constant over frequency - they are just not - I don't care what the substrate suppliers say - Ive measured them (remember - 10 years min). As a result you need to take that into account - remember the breakoffs.e) The best way to take these last few points into account is via a pure lumped solution using high Q components packed as tight as you can. Forget about transmission lines - they don't work - NEVER lay out 50 ohm lines on FR4 - you are better to give up some mismatch than to put up with dielectric loss (remember - 10 years min)f) Use their units. They don't give a shit if you are American and too fucking stupid to have converted to metric. The world has spun and what the fuck have you been doing for the last 10 years. Their education is typically better than yours. If you don't believe me sit in a Chinese University and sit in a US university and compare. I have and I know what the situation is. I also go to their conferences and they are superior to US conferences. Sorry. Forget the hype - US education has declined into garbage - remember they can do specialist electronic engineering degrees. In the US you can do a basic electrical engineering degree with none to few advanced options let alone product design. A US Masters may be equivalent to a Chinese Bachelors if you are lucky. I did a US masters and it was garbage. Too many adjuncts and not enough experience in the world. I haven't heard of imperial being the choice units in China for more than 10 years. Again - they don't give a shit what you want - they have already pivoted to supporting their local economy. Basically they are now driving the Electronics industry and are probably 5 years ahead. They have a process and you are using it because they are cheap. You don't like it? go to an American vendor - that won't last long because US shit is even worse - no discipline, management thinking sucks ass and education is poor. You get what you pay for and in China if you don't go so cheap you will get something much better. The US equivalent for that something better will cost you an arm and a leg - in the US board makers are still shipping non masked boards. They can't compete so everything is just worse. Electronics is almost dead in the US so just remember that - they are pumping and the US is dying - finding real R&D hardcore electronics porn work is getting hard in the US - at best its iterative improvements in the US 95% of the time. I go to US conferences and its hype with dickheads with big mouths and good hair - just dilbert stuff. I usually walk away with not a single usable idea.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: May 09, 2020, 04:06:26 pm
content: Quote from: intmpe on May 09, 2020, 03:31:06 pmThat is odd. In my dealings with one the biggest telecomunications device manufacturer from China, they:- Used transmission lines everywhere- Used mils all the time, to my great frustration, because I prefer microns (incidentally, all design rules I've gotten from their manufacturers also are written in mils, not mm/um)- Used lots of substrates, including Isola, Megtron, next to FR4- Defined exact stackups that were to be followed to the letter- Define impedance controlled boards and enforce thatSo perhaps, in your great experience and wisdom (10 year min.), just failed to find the good manufacturers. Could be they were just to lowly for someone with your minimum 10 years of experience.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: May 09, 2020, 04:21:42 pm
content: Quote from: blueskull on May 09, 2020, 04:15:25 pmI imagine it is likely, but that is beside the point - I just wanted to pose a counterexample to the sweeping generalizations and 'you are doing it wrong' phrasing of intmpe's reply.

author: OwO
author_rank: Super Contributor
timestamp: May 09, 2020, 05:50:38 pm
content: Transmission lines on FR4 are fine - on non impedance controlled boards I haven't seen more than 10% variation, and impedance controlled boards are usually better than 5%. Of course you have to vet your boardhouse well to be sure they are actually doing impedance control. I usually use a mix of discrete and distributed components. For example capacitors < 0.5pF or inductors < 1nH I will prefer to put a stub instead. For higher power/lower loss you can cut away the in1 layer and drop down to in2 as ground reference, to get ~1.2mm dielectric height. I've done this for a wilkinson power combiner on a 5.8GHz power amplifier.

author: david_geng
author_rank: Newbie
timestamp: February 22, 2021, 10:22:49 pm
content: I think FR4 is ok for 6GHz even up to 8GHz. Here is a test with VNA on a 4ly TG155 board. The test trace is 1inch long with SMP connectors.

author: Rfpcb413
author_rank: Newbie
timestamp: August 11, 2025, 01:10:26 pm
content: 4350B 0.102 Hoz 18*24 around 40-45USD