"Cheap" RF pcb Manufacturer - Page 1
Forum section: electronics / rf-microwave

author: dmowziz
author_rank: Contributor
timestamp: September 13, 2024, 02:25:04 am
content: HiPlease can someone recommend a pcb maufacturer that produces boards with a known and tight ErThanks

author: fourfathom
author_rank: Super Contributor
timestamp: September 13, 2024, 06:00:37 am
content: Have you looked at JLCPCB? They have Rogers and PTFE dielectrics available. I've not used any of these, and I don't know how cheap and tight you want, but take a look:https://jlcpcb.com/blog/rogers-pcb-ptfe-pcb-high-frequency-pcb-is-available-on-jlcpcb

author: ftg
author_rank: Frequent Contributor
timestamp: September 13, 2024, 08:16:47 am
content: Allpcb also has some offerings that are competitively prised, but you really need to order +10boards to start getting good pricing.The JLC manufactured teflon boards I have handled seemed fine. They were cheap for teflon, but still way more expensive than FR4.

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: September 13, 2024, 08:33:36 am
content: I have had quite a few boards made by JLCPCB and they are low cost, fast and excellent. However, what do you mean by RF? I have had boards made by them for a 1 GHz RF probe, a GPSDO operating at 10 MHz as well as power supply protection boards. I just opt for the cheapest board type, sometimes picking a nicer colour than green if it costs the same... Delivery to the UK takes roughly 2 weeks from uploading the zip file. Boards are as little as 5 GBP for 5 board delivered including tax!SJ

author: dmowziz
author_rank: Contributor
timestamp: September 13, 2024, 09:29:00 am
content: Thanks guysI was looking at JLCPCBI do not know if I'm doing this the wrong way, am I? :I have been etching at home with Isola's I-TeraMT40 Laminate and it has a specified ErMaking a filter at 433MHz for example, knowing the accurate Er makes simulation and prototype to agreeSo I am looking for a manufacturer that sells pcb's for cheap (less than $50) using a laminate with known Er (preferably using Isola laminates)

author: ftg
author_rank: Frequent Contributor
timestamp: September 13, 2024, 12:15:46 pm
content: JLC's RF laminates (Rogers and their PTFE) will do known materials with known Er in two layers.For FR4 you have to go to 4layer process at JLC to get predicatable materials with datasheets.As for 2layer FR4 they use whatever that has the right thickness. So the Er can be all over the place and vary from batch to batch.Allpcb does have fixed materials stackups for 2layer as well. And you can get proper datasheets for the substrates.We have made antennas with their 2layer and 4layer process with repeatable success.For 433MHz it depends a bit on the type of filter if it is viable on FR4 as well.It has potential to be rather big and thus expensive RO4350B or teflon.More so thanks to both having a lower Er than FR4 and thus your design taking more space.Your 50usd budget could fit one board, but potentially not five.The 4x4 10GHz panel antenna on their teflon was 30eur/pcb in a batch of five.

author: abby1319
author_rank: Newbie
timestamp: February 12, 2025, 06:28:47 am
content: www.zb-pcb.com, we have been specailizing in RF PCB for over 10 years.Send us your file to abby@zbwbpcb.com for a quotation.

author: EggertEnjoyer123
author_rank: Frequent Contributor
timestamp: February 12, 2025, 08:07:10 am
content: Here's an example of a 6 GHz filter I made on JLCPCB's 4 layer FR-4 substrate. 433MHz should be pretty simple. You can probably use a thin 2 layer substrate.You can get the substrates they use by talking to customer support over the chat.

author: ftg
author_rank: Frequent Contributor
timestamp: February 12, 2025, 11:16:24 am
content: The problem with JLCPCB's 2 layer service is that they will not guarantee the substrate used.It's a lottery what laminate is used. And thus if your Er is 4.3 or 4.6.

author: stretchyman
author_rank: Regular Contributor
timestamp: February 12, 2025, 12:20:41 pm
content: Same question asked so many times.Same answer.JLCPCB.

author: tchicago
author_rank: Regular Contributor
timestamp: February 12, 2025, 08:08:15 pm
content: Quote from: EggertEnjoyer123 on February 12, 2025, 08:07:10 amDid you use top two layers? I.e. one layer on top, and one internal layer closest to the top?Do you use JLCPCB's calculator to calculate the 50 ohm line or the formulas from popular books like "Microwave Engineering" by David M Pozar using JLCPCB's stated Er and thickness of dielectric between top two layers? I find that the trace width from JLCPCB's calculator is significantly different vs formulas.I ordered a sample PCB design having two 6cm traces of 50 Ohm line terminated to SMAs on both sides using both formulas, using JLC's 4-layer stackup with guaranteed material type and the result was a disaster. Neither line was 50 Ohms. Also, the losses were very high.I then ordered that same PCB with same 4-layer stackup, but using the top and bottom layers only. With traces recalculated to a different dielectric thickness. The results were MUCH better, with the trace width from book formulas having best proximity to 50 Ohms. The losses were also much better, shaved off 5..7dB at higher frequencies. But the trace width of nearly 3mm is pretty hard to work withI suspect that the either stackup parameters (thickness) they gave are wrong or they used a wrong dielectric in first case or both...

author: dcarr
author_rank: Regular Contributor
timestamp: February 12, 2025, 08:54:29 pm
content: Give coplanar waveguide a shot if you're trying to do RF on 2 layer or poorly controlled PCBs. You can get much narrower traces and a lot of the field is in the air so the dielectric influence is smaller.

author: EggertEnjoyer123
author_rank: Frequent Contributor
timestamp: February 13, 2025, 01:37:45 am
content: Quote from: tchicago on February 12, 2025, 08:08:15 pmI used the calculator on the JLC website. I use 0.35mm for normal microstrip on their 4 layer board (with 0.2104mm gap between the top two). I use 0.3mm for the GCPW case with the ground being 0.2mm away. Here are my results for a 17.7mm through (with connector loss included). The blue line is the loss of that board, which is 17.7mm long, and the two connectors. Ignore the brown line (I am testing an 0201 capacitor). The results fit nicely with the expected 0.2 dB/GHz/in loss for FR4.My guess is you actually ordered the wrong 4 layer impedance matched board, since one of them has a gap of 0.1mm and the other has a gap of 0.2104mm between the top two layers.The stackup I used was microstrip on the top layer, and ground on the 1st inner layer.