FR4 PCB height for 1.4 GHz

I designed a FR4 PCB which is 1mm height,But the PCB company made it 1.5mm,so I want to know if I use the 1.5mm pcb,is it ok?my Fo is 1.4GHz.

you should scale distributed lines width.
And generally speaking, bigger is the thickness, smaller are Cu losses.

I believe the poster would like to know whether he can use the FR4 PCB or not, having an incorrect thickness of 1.5 mm instead of 1.0 mm.

Well, it depends on the application. A 100 mm long 50 ohm transmission line designed on a 1.0 mm FR4, has a width of about 1.84 mm. The result using this width on both a 1.0 and 1.5 mm FR4 is shown in the simulations below. Note the bad return loss when used on a 1.5 mm FR4.

The third plot shows a 4-pole Chebychev sidecoupled bandpass filter designed and optimized on a 1.0 mm FR4. The result using exactly the same filter on a 1.5 mm FR4 is shown in the last plot. The result speaks for itself.

In my experience definitely it is not OK!

There are couple of issues at 1.4GHz...

If you have lot of discontinuties & coupled lines in that PCB design...
it matters lot, so resimulate the critical potions of the design in Circuit simulators or using EM Simulators....like AWR MWOffice or Agilent ADS

Again agree with VSWR it depends on your application & design complexity...

I simulated a simple Microstrip 50 ohm line for your substrates specs...see the results how it varies...


Frequency DB(|S(1,1)|) DB(|S(2,1)|) DB(|S(1,1)|) DB(|S(2,1)|)
(GHz) 50_Ohm line H_1_0mm 50_Ohm line H_1_0mm 50_Ohm line H_1_5mm 50_Ohm line H_1_5mm
1 -33.771 -0.080735 -14.659 -0.22204
1.05 -33.539 -0.084325 -14.453 -0.23326
1.1 -33.342 -0.087893 -14.277 -0.24369
1.15 -33.177 -0.091439 -14.131 -0.25325
1.2 -33.043 -0.094962 -14.014 -0.26185
1.25 -32.94 -0.098464 -13.925 -0.26945
1.3 -32.867 -0.10194 -13.862 -0.27599
1.35 -32.823 -0.1054 -13.826 -0.28143
1.4 -32.809 -0.10884 -13.817 -0.28575
1.45 -32.824 -0.11227 -13.833 -0.28895
1.5 -32.868 -0.11567 -13.876 -0.29101
1.55 -32.941 -0.11906 -13.945 -0.29196
1.6 -33.045 -0.12243 -14.042 -0.29183
1.65 -33.18 -0.12579 -14.166 -0.29065
1.7 -33.346 -0.12914 -14.319 -0.28848
1.75 -33.546 -0.13247 -14.502 -0.28539
1.8 -33.781 -0.1358 -14.716 -0.28145
1.85 -34.053 -0.13913 -14.964 -0.27675
1.9 -34.363 -0.14245 -15.247 -0.27138
1.95 -34.716 -0.14577 -15.567 -0.26546
2 -35.114 -0.14909 -15.929 -0.2591


Go through the attached PDF doc for more details...