Re: NEC-LIST: material question

Found some more data:
epsilon 2.8-4
dissipation factor 0.03-0.55 (that's pretty horrid, all things considered)

ANother reference gives: 2.6 @ 1MHz, with loss tangent of 0.014 @ 1MHz

However, Rexolite (which is also an acrylic) has very low loss (they use it
for radomes, for instance)

Here's more data than you really need: (courtesy Ed Harris and Richard Quick)

polymer dielectric dielectric dissipation
                 constant strength factor
                 50Hz / 1Mhz (Kv/cm) 50Hz / 1Mhz (x10^-3)
-------- ----------- ----------- -----------
LDPE 2.29 / 2.28 370 .15 / .08
HDPE 2.35 / 2.34 -- .24 / .20
PP 2.27 / 2.25 240 .40 / .50
PVC-plasticized 4-8 / 4-5 270 80 / 120
PS 2.5 / 2.5 200-300 .1-.4/.05-.4
ABS 2.4-5/2.4-3.8 ~400 3-8 / 2-15
PMMA 3.3-3.9/2.2-3.2 140 40-60/4-40
POM 3.7 / 3.7 400 5 / 5
PTFE 2.1 / 2.1 480 .2 / .2
PCTFE 2.3-2.8/2.3-2.5 550 1 / 20
PA-6 3.8 / 3.4 400 10 / 30
PA-66 8 / 4 600 140 / 80
PC 3.0 / 2.9 380 .7 / 10
PET 4.0 / 4.0 420 2 / 20
PI 3.5 / 3.4 560 2 / 5
PUR-linear 5.8 / 4.0 >300 120 / 70
PUR-thermoset 3.6 / 3.4 240 50 / 50
PUR-thermoplas 6.6 / 5.6 300 30 / 60
CAB 3.7 / 3.5 400 6 / 21
Silicone 3.6 200 5-13 / 7

Another comparison:

polymer Dielectric constant / Dissipation Factor (x10^-3)

                 100 Hz 1000 Hz 1 Mhz 10 Mhz

ABS 2.8/5 2.8/6 2.8/8 2.8/7
PMMA 3.6/62 3.2/58 3.1/40 2.9/33
PC 3.1/1 3.1/1.3 3.1/7 3.1/11
PE 2.3/.1 2.3/.1 2.3/.1 2.3/.1
PA-6 4.2/31 3.8/24 3.8/31 4.0/20

-------

There's lots of acrylics out there, and they do absorb water (as anyone who
ever put acrylic in a vacuum system found out), which would change their
dielectric properties.

At 07:12 AM 2/3/2004 -0800, zvi frank wrote:
>Thank you everyone for the prompt response,
> Zvi
>
> > -----Original Message-----
> > From: Jim Lux [SMTP:jimlux_at_earthlink.net]
> > Sent: â 03 ôáøåàø 2004 17:08
> > To: zvi frank
> > Subject: Re: NEC-LIST: material question
> >
> > PolyMethylMethacrylate - Plexiglas(r) or more generically "Acrylic"
> >
> > Dielectric constant is around 2-3, not horribly lossy, but I wouldn't want
> > to go making a high power RF capacitor of it.
> >
> > ----- Original Message -----
> > From: "zvi frank" <zvi_f_at_mti-group.co.il>
> > To: <nec-list_at_gweep.ca>
> > Sent: Tuesday, February 03, 2004 4:38 AM
> > Subject: NEC-LIST: material question
> >
> >
> > > Does anyone know the electrical properties of perspex ,dielectric
> > constant
> > > and loss tangent? What is the chemical name for perspex?
> > >
> > > zVi
> > >
> > > --
> > > The NEC-List mailing list <nec-list_at_gweep.ca>
> > > http://www.gweep.ca/mailman/listinfo.cgi/nec-list
>
>--
>The NEC-List mailing list <nec-list_at_gweep.ca>
>http://www.gweep.ca/mailman/listinfo.cgi/nec-list

James Lux, P.E.
Spacecraft Telecommunications Section
Jet Propulsion Laboratory, Mail Stop 161-213
4800 Oak Grove Drive
Pasadena CA 91109
tel: (818)354-2075
fax: (818)393-6875

-- 
The NEC-List mailing list <nec-list_at_gweep.ca>
http://www.gweep.ca/mailman/listinfo.cgi/nec-list