rf pcb materials
FR4 is very poor and only used where cost is more important than performance. Gtek is better and only slightly more costly. If performance is important, use the traditional materials such as those from Rogers Corp.
http://www.rogers-corp.com/acm/litintbl.htm
Rogers is great supplier. However, beside loss you sometimes might have to consider some other details such as dimension of the circuit (then you will go for high Er to reduce size), manufacturing tolerance (then you will go for thicker substrate to make line wider) etc.
flyhigh
but i have questions ,if simply considered for circuits better performance,what the fundamentals?
Yes,the PCB materia supplied by Rogers is very good.But it is more expensive than RF4.
You can use the kind of material that the dielectric
equal to 2.2.It is very stable .
Good Luck.
for no high power required ,FR4 is ok. It is cheap.
Often used for mixed-signal PCB.Dielectric constant often 4.2to 4.7 .
If for PA board, less loss material is needed.
Hi,
You should use Roger R4003 with an Er of 3.35 it is perfect for this freq range, it all depents on what you are designing on the PCB.. if you plan to make more than just 50 Ohm lines than you should go for this material otherwise use GTek which is cheaper but still better than FR4..
The problem with FR4 is not only the loss but the Er it is not defined and thus varies depending on supplier. The Er of FR4 can be anything between 4 and 5 and this will make complex structures on FR4 impossible...
If you make a PA and you plan to use a matching network on the PCB you should go for R4003..
Paul.
Roger product is good but expensive. Since your design is only up to 6 GHz, you can consider using Roger RO4350 (er=3.48) as the price is the cheapest among Roger products. Though FR4 is cheap but it is very lossy at 6 GHz. RO4350/RO4003 is recomended. Attached is the product spec.
Except Rogers there is also another company.
ARLON. Does anyone paid some comment to this one?
I know this one has same characterister with rogers in RF PCB material in high requirement level.
FR4 is not suitable for operating frequency over 3GHz because of lose.
Can anyone explain the procedure of selecting the PCB material with particular Er with respect to frequency?
Lets say if I wanna design some PCB in freq range 9 to 11 GHz then how to choose Er and then PCB material?
Please help me in understanding.
Please ggogle for RT duroid copper clad for microwave frequencies and you get the first link from Rogers as PDF.
if you can check this link, you would get the right type
It is well informed already by others that Rogers is the best source.
Depends on the design. If you need something very thin with high dielectric, you'll choose based on that. If you need something very low loss at a certain frequency, choose based on that. Rogers makes lots of good, general purpose composites. If you need higher Er I think Dupont makes some good low-loss, high Er boards but they're more expensive.
If you're going really high frequency there are specialty composites for that, too. Just google around and you'll find info. Rogers is good, Arlon makes some quality materials, FR4 is cheap, etc etc.
Thanx Sir for providing the relevant information about the material........I have just started in this field......it will be helpful if u could also provide some link where I can learn designing of RF PCB layout from scratch.
for so high freq, it is very sensitive. FR4 should not be a choice.
Hi guys, I'm new here.
If the purpose of PCB design for high frequency up to 20GHz, which Roger material suitable to be use? And how we want to relate between the performance of PCB board with the Dielectric Constant?
RO4350B 10mil 1/2oz is ok up to 20GHz.
Dielectric costant is relate to trace width. When you simulate, you must use it
tq sir. 8)
Bigger εr means that for the same elelectrical length, the physical line length shrinks. Depending on your etching tolerances, it might be better to use small εr with longer lines, to reduce the relative error from manufacturing.
Same for the dielectric height: for a given line impedance, thin substrate means that your line width and gap width shrinks. If you need coupled lines for filter, check if these can be realized for the given substrate height. If gaps and lines would be too narrow, a thicker substrate might be the solution. If you need vias through the substrate, thinner substrate will give smaller inductance.
I use Arlon, the material is not so rigid as Rogers, but I always get good results, and is easier to manufacture with a Milling Machine or LASER.