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On Thursday, September 1, 2022 at 11:32:32 AM CDT, W0LEV <davearea51a@...> wrote:

Yes, I spaced the Rogers products.? Thank you for mentioning the Rogers
4350 substrate.

FR-4 is available everywhere and is relatively inexpensive.

What's more and being critical, both the dielectric constant and dielectric
thickness of FR-4 board may vary across a large sheet.? Been there, done
that being paid to force Fibre Channel "square waves" across 15-inches of
FR-4 with no dispersion.? Bad things happen for EMC/RFI when the
pre-emphasis is jacked (by the designers to make it function) in an attempt
to accomplish that stated goal.? The GM of the division dictated absolutely
bargain basement prices on every component of the system.? Ultimately, he
got egg on his face and I was banned from working further with that
division.? Standard practice with the present-day Corporate America:? Slay
the messenger!!

Dave - W?LEV

On Thu, Sep 1, 2022 at 3:51 PM KENT BRITAIN <WA5VJB@...> wrote:

? Hi Dave
Very very difficult to get Duroid processed these days.I don't know of any
US shops that will touch that stuff any more.(Rumors of one in California
with a Plasma etcher)
If you want plated though holes, you have to etch the raw material to make
it porous enough to take the Copper.? Do you know what kind of chemicals
are necessary to etch Teflon!!!? ? Stuff the EPA does not like!
Rogers 4350 is a ceramic filled material that uses FR4 processing.? Not
quite as low Er and loss tangent as Duroid, but it's not bad.? And regular
PCB houses can process it.? Kent


? ? On Thursday, September 1, 2022 at 10:43:29 AM CDT, W0LEV <
davearea51a@...> wrote:

? I was also going to suggest you actually measure the εr of the PCB you
actually used at the frequency you intend to use it.? The εr of FR-4 board
falls between an upper an lower limit, but it is not controlled.? If you
want something more controlled and predictable, use RT/Duroid, but it is
expensive.? Also, Teflon board is also better controlled than FR-4, but
also expensive.? Both are far better substrates for microwave applications.

Dave - W?LEV

On Thu, Sep 1, 2022 at 10:31 AM Diane BONKOUNGOU <dianebonk2@...>
wrote:

Hello everyone,
I used OpenEMS software for my simulation and I got simulation results
that are very different from my experimental result, I have a PCB antenna
whose resonant frequency is around 2.4GHz. I design the same thing on
OpenEMS but the simulation gives me a resonant frequency of around

2.66GHz.

Such a difference of 0.2GHz is important in RF, isn't it?? Knowing that

the

frequency range of Bluetooth Low Energy is 2.4-2.5GHz.
I have calibrated very well my NanoVNA and my experiment result must be
good. I know that because I tested the Texas instrument PCB IFA antenna

and

I get the same result as in their Datasheet.
Can you recommend a free tool for antenna simulation?
I have searched but I can only find OpenEMS based on the FDTD method. The
others are professional and paid tools for PCB trace antenna simulation.
Best regards.

--
*Dave - W?LEV*
*Just Let Darwin Work*


--
Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*


--
Dave - W?LEV