[SI-LIST] Re: Loss tangent and Dielectric conductance
- From: "Ken Cantrell" <Ken.Cantrell@xxxxxxxxxxx>
- To: "Yaping Zhou" <y.zhou@xxxxxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Mon, 5 Nov 2001 08:18:48 -0700
Yaping,
Thanks for the input. That makes sense. No, I don't know of any way to
separate conductor loss from dielectric loss when doing TDR measurements.
Not in the actual measurements themselves. I obtain the relative
permittivity from the relative velocity/free space velocity ratio, and
crunch some closed form solutions for conductor loss, compare to the total
loss, and what's left is the tan delta loss. It gets you in the ball park,
but it's a best fit for that particular case, and not a general solution.
Ken
-----Original Message-----
From: Yaping Zhou [mailto:y.zhou@xxxxxxxxxxxx]
Sent: Sunday, November 04, 2001 11:24 AM
To: Ken.Cantrell@xxxxxxxxxxx; si-list@xxxxxxxxxxxxx
Subject: Re: [SI-LIST] Re: Loss tangent and Dielectric conductance
Ken:
I think the most accurate way to measure dieletric constant is to use high-Q
cavity. The cavity is calibrated first, then a small piece of material is
put in. The resonance frequency shift and Q decrease are measure with VNA.
The frequency shift can be related to the real part Er' and the Q decrease
is related to the imaginary part Er''. Loss tangent is the ratio of Er' and
Er'' .
A metallic trace has to be added for TDR measurment. By doing so we
introduce additional conductor loss, which usually dominates dielectric
loss. Is there a way to separate conductor loss and dielectric loss in TDR
measurement?
Yaping
--
**************************************
Yaping Zhou
Motorola Semiconductor Products Sector
Final Manufacturing Technology Center
Ed Bluestein, Austin, Texas
**************************************
----- Original Message -----
From: "Ken Cantrell" <Ken.Cantrell@xxxxxxxxxxx>
To: <omism@xxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
Sent: Thursday, November 01, 2001 12:14 PM
Subject: [SI-LIST] Re: Loss tangent and Dielectric conductance
>
> Pete, Ozgur, et. al,
> That's the right formula, but the trick is in actually knowing what the
loss
> tangent is. Vendor data for standard formulations (FR40X, GTEK, Rogers,
> etc.)can be quite divergent from TDR derived permittivity (then up scaling
> the permittivty to the frequency of operation), and fitting the loss
tangent
> to the dielectric portion of the total measured loss - Vout/Vin (dB).
> Anyone know of any good texts or literature sources on the subject?
> Ken
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx
> [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Ozgur Misman
> Sent: Thursday, November 01, 2001 9:38 AM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: Loss tangent and Dielectric conductance
>
>
>
>
> Actually formula do exist,
> I must have missed the capacitance in tmy previous E-mail
> let me rewrite it as
> Gd=2*pi*f *tand*C (capacitance)
> C=Er*Co
> Co= Eo A/d
>
> Mick is right in saying that the dielectric loss is a property of the
> material and conductance depends on the circuit as well. That link is in
> the capacitance term.
> The formula is derived assuming a resistance in parallel with
> capaciatance.and conductance is defined as 1/resistance.
> Hope this clarifies
>
> Ozgur Misman
> ---------------------- Forwarded by Ozgur Misman/CHAZ/AAWW on 11/01/2001
> 09:34 AM ---------------------------
>
>
> 11/01/2001 08:51 AM
> Ozgur Misman - Chandler - 5080
> Sr Engineer
> 01 We've Just Begun
>
>
>
> To: plaflamm@xxxxxxxx
> cc: si-list@xxxxxxxxxxxxx
>
>
> Subject: Re: [SI-LIST] Loss tangent and Dielectric conductance (Document
> link: Ozgur Misman)
>
> Hi Peter,
> I think the for mula is : Gd (conductance)=2*pi*frequency*tand(loss
> tangent)* Eo (permittivity of the free space;8.854e-12f/m)* dielectric
> constant;Er
> Ozgur Misman
> Amkor Technology
>
>
>
> Peter LaFlamme <plaflamm@xxxxxxxx>@freelists.org on 11/01/2001 06:45:13 AM
>
> Please respond to plaflamm@xxxxxxxx
>
> Sent by: si-list-bounce@xxxxxxxxxxxxx
>
>
>
> To: si-list <si-list@xxxxxxxxxxxxx>
> cc:
>
>
> Subject: [SI-LIST] Loss tangent and Dielectric conductance
>
>
>
> Hi SI Folks,
> I would like to know the relationship between Loss Tangent and Dielectric
> loss. In other words, If I know the "loss tangent" at a given frequency
for
> a particular dielectric what is the formula to convert this into the
> Dielectric conductance(Gd) ?
>
> Thanks,
> Peter
>
> --
> Peter LaFlamme
>
> Applied Micro Circuits Corp.
> Staff System Applications Engineer
> 200 Minuteman Rd, 3rd Floor
> Andover, MA 01810
>
> 978-247-8470 phone
> 978-623-0055 Fax
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