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72 Threads found on edaboard.com: Dielectric Constant fr4
fr4 is not a good material to use at 1 GHz. Use high frequency materials that has a more stable dielectric constant with less loss.
you can mesure your own pcb dielectric using this way: 1-obtain the 2 layer pcbof area A 2- connect two wire in two side of PCB 3-using LCR meter and mesure the value of capacitance 4- using the formula of parrallel plate capasitor C=e0erA/d
Anyone pls tell me how to find the dielectric constant of an unknown fr4 board using microstrip line... Then if I have a Er =4.7 fr4 board @ 100 MHz ... anyone can tell me how to find the Er of this board at 4 GHz. Thanks.
hi. as i could find out, most of the fr4 manufacturers give the dielectric constant at 1MHz in the datasheets. some of them provide the Er at 1GHz. if my board works on 400MHz (also not exact, because its a digital signal, so it has a spectrum...), then i can only estimate the Er, so my impedances on board will have a big tolerance. (...)
hi all! is fr4 a standard? i mean if one material is said to be fr4, will other fr4 materials have the same characteristics? also, will the dielectric constant change with the width of the fr4? thanks much vpm
It is a very simplistic papaer, using closed form equations to approximate microstrip impedances. No attention to microstrip disconinuitites was made, such as end effect, connector effect, radiation, dispersion, ........ And, could be a mistake in the equation derivations too. Better transmission line type dielectric measurements utilize a s
Hi all, My 1 mm fr4 board warps all over the place when heated. Do u know of a cheap PCB substrate with similar dielectric constant to fr4 but is stiffer? Thanks You have to compromise either on the price or the quality. Naturally you cant expect sugar at price of salt. :D Cheers
I am making a pcb antenna which has a resonant frequency at 13.56 mhz and which will be etched onto a fr4 substrate What value for the dielectric constant am I looking for in the substrate at this frequency and why? how can I determine the dielectric constant at a 13.56 mhz given the (...)
fr4 is a composite material, in most cases its a good approximation to assume a dielectric constant Er of 4.2 The two main constituents of fr4 are glass with an Er of around 6 and resin with a dielectric constant of around 3. Typically manufacturers quote a dielectric (...)
Do a site search for fr4. This topic has been discussed to death before. In general, since fr4 was not intended originally for RF, the dielectric constant does not have a specific value all vendors design to. It varies over a very wide relative range because of the different ratios of chemical components used by (...)
A microstip transmission line is a printed circuit trace over a conducting plane with a dielectric between the trace and plane. A stripline would be a trace between two conducting planes with dielectric between the trace and the planes. FR-4 is a specification for printed circuit board dielectric material. The designation stands for (...)
The usable frequency for fr4 depends on what kind of circuit you have, and what fr4 you are using. fr4 is not just one material with one set of characteristics - the fr4 rating only specifies what the flamability of the material is. Circuitwise, you can design compensation for some losses that extend the usable (...)
Hello Friends, I 'm trying to find the impedance of a rectangular 10*1 cm^2 of a pcb fr4 two layer copper 0.025mm per layer and h=1.55mm I tried to measure but that was not satisfactory and i 'm trying to compare measuring the impedance and then I will find the dielectric constant. Thanks
As the antennas are printed on a PCB there will be some coupling mechanism inside the dielectric but also just outside the PCB top layer. I'd say the mutual coupling is mostly coming from just outside the PCB since fields inside the PCB are more confined. So the antenna sees an effective dielectric constant with a value somewhere between (...)
Hi, I would like to know if a multilayer PCB with a high dielectric constant (e=10) and low losses at high frequencies is possible to manufacture. Thanks a lot.
The high DK substrate's dielectrical strength may be considerably lower than of standard material. I noticed, that Rogers even don't specify it in the datasheets. Generally, I think there are many design options to build the intended circuit, you aren't restricted to simple microstrip. It's just engineering, I'm sure, others have solved similar
what is the frequency range that this substrate support??? There is no clearly defined frequency range. fr4 has much more dielectric loss than "good" microwave substrates. If loss does not matter, you can use it at high frequencies. But if you need low loss for microstrip filters, then fr4 is a bad choice. The permit
But why is dielectric needed?
Thanks.... may i get information about practical calibration of dielectric material?
You have to have something between the copper layers! The properties you would want are high resistance, mechanically rigid & stable, low moisture absorption and maybe some others. Every material has some dielectric constant. For RF design that can be critical so boards with specific dielectric constants are available, but (...)
fr4 subtrate is economical for students but results wont be satisfactory becoz its nt efficient....dielectric constant is 4.4 for dis.
FR-4 dielectric constant = 4.5 & Loss Tangent = 0.021 Standard fr4 thickness are 0.8, 1.0, 1.2, 1.5 and 1.6 mm.
If your application is critical, please note that the actual value depends on frequency, temperature, manufacturer and batch. You may see values between 4.4 and 4.8, depending on resin formulation and glass content. Hi WimRFP, I thought the 4.4 - 4.8 is the dielectric constant of fr4? If i am not mistaken, permeabil
Beware that there are many different suppliers, which are interchanged by the PCB manufacturers frequently for cost reduction. Ans all have different dielectric constant and loss tangent. So in short you can only use fr4 in case you can live with these larger variations by taking it into account during the design phase.
Hi, I would like to know the dielectric constant and the loss tangent values for fr4 at 5.9GHz. Do these parameters vary with the material thickness? Thanks,
I wish to make a fixture/tool that is able to measure dielectric constant. after researching through the web and read numerous papers and application note. i decided to try this at page 5. using parallel plate capacitor id
When you press the boards, the dielectrics will touch and it will look like a single piece of dielectric to EM waves. The minor discontinuities in the dielectric will barely affect the dielectric constant. As for the dielectric thickness, you should look at the overall thickness dimensions (...)
Hi guys, I really need help for my senior project, I'm very clueless. I'm trying to design a coupled line BPF 0.5 equal-ripple when the order(N)=3, center frequency=2GHz, bandwidth=10%, Zo=50(ohm) and attenuation at 5 GHz - many of you will find this problem familiar since it's from Pozar's microwave engineering text
Er is dependent on the dielectric material used (4.3-4.5 average for fr4 based PCBs. Z0 is dependent on the topology used on a PCB design, number of layers proximity to planes etc etc. Download and play with this:
The insertion loss due to dielectric Absorbtion is less in Teflon. But it hardly matters in the audio range. fr4 is much cheaper to use.
And how we want to relate between the performance of PCB board with the dielectric constant? 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
galilu, :) fr4 with copper is most ordinary pcb I know. It has a dielectric constant of 4,3 to 4,9, depending on manufacturer. But to be more specific: at what frequency do you want to use it? Maybe if you give me some details I can help you.
Prop delay in fr4 material is about 150 Ps/in for microstrip and about 170 Ps/in for stripline with a dielectric constant of about 4.5 if you have a microstrip trace 2 inches long it would be 300 Ps, if the trace then transitions to an inner layer and travels 2 more inches the additional prop delay is 340 Ps, total prop delay = 300+340 or (...)
the track length can be calculated only if the board material with its dielectric constatnt is know . For eample for fr4 material with 4.7 dielectric constant 1inch = 180 ps ? = 50 ns (50000ps) ANSWER =277 inch
dielectric constant vary with diferent manifaturers, but in general is about 3,7-4,7 for FR-4 material. There is special materials with higher ε for special RF proposses. They based on same ceramics matiral and tipicly ε is in region of 9- 10 at the working frequencies. This "higher" dieledtric constant, helps to keep phisical (...)
Core is the dielectric material between two copper layers which forms a Laminate, & prepreg is the dielectric material which is used to bond thes laminates
Parameters H = substrate thickness, in specified units Er = relative dielectric constant Mur = relative permeability Cond = conductor conductivity, in Siemens/meter Hu = cover height T = conductor thickness, in specified units TanD = dielectric loss tangent
hello buddies... I have one clock signal for one circuit and I want to use same clock signal for other circuit but for other circuit clock should be slightly delayed.Let say I want to delay by 0.7 ns or 0.3 ns....how can I introduce precise delay in clock.Which components are useful for introducing delays...Please help urgentl
Actually the number I cited above is incorrect - I was refering to propagation delay which for fr4 is about 176 pico seconds per inch for internal traces and about 155 pico seconds per inch for external signals - this is a measure of how long it takes a signal to travel a given distance and is determined entirely by the dielectric constant (...)
One problem with fr4 is the variation in its dielectric constant from batch to batch. It can vary by at least +/- 0.5. Maybe your antenna design can take this variation. A quick simulation check using the extreme values for the dielectric constant will answer this. If this is acceptable then fine, use (...)
Hi These datas are insufficient to calculate the Impedance. You should know the dielecric thickness from the reference plane, trace thickness, dielectric constant of the material, loss tangent, operating frequency. you can download the calculators from ultracad. Good Luck! Nagaraj.
I want to use HFSS to simulate a slot line structure with the fr4 material as a transmission line to get the characteristic impedance and effective dielectric constant. The first question is about the port, should I use the wave port or the lumped port? Well, lumped port is better for the microstrip line structure, for the field is (...)
i am designing microstrip antenna for bluetooth........can any one provide me some help...freg is 2.4ghz,substrate duroid having dielectric constant 2.32 and thickness of substrate is 0.127
Hi all, Could any one tell me how to get the detail specifications and vendor information of GTEK and BT laminates of PCB substrates ? i would like to comapre these two laminates with fr4 to see the difference as below : 1. Density ( g/cc ), 2. Coefficient of Thermal Expansion CTE, 3. Glass transition temperature, 4. Deg
Since you are working on a monopole a very thin dielectric may work well as a support while still remaining transparent to the RF signal.
If you're looking for a check list, here's a basic one: 1) Make sure you know the dielectric constant of the board. If you use fr4, and are really high frequency (say 4 GHz) or higher, you may need to design for losses along traces. This is because the dielectric constant of fr4 is only (...)
Is your PCB material fr4? fr4 material is extremely inconsistent in its dielectric constant. Also, it's stacked layer thickness varies from different vendors.
Anybody can help me to figure out some hints on the PCB characteristics under high AC voltage? It is ESD generator discharged current/voltage, the max voltage can be up to ~4KV, even higher, and the rising edge could be 0.7~1ns. I am considering if the fr4 eproxy material dielectric constant and loss tangent would change at such high (...)
Depending upon your circuit if only transmission lines are there then fr4 is good it has a dielectric constant of 4.4. RT duroid is much much better but costly. You can simulate the results with both materials and can see the difference which is better for you circuit. Hope it helps
hi there, i need to design a 4 element patch antenna array. i have 6inches (w) by 4inches(h) fr4 board. i need to design the array so that feed network, array and impedeance transformer all fit on the stated board can someone please 1)suggest an appropriate operating frequency for the array 2)tell me the dielectric constant, loss tangent (...)