Mail*Link(r) SMTP               FWD>FAB:  Dissipation Loss Specs

John,

In brief, "dissipation loss (factor)" is the energy absorbed (lost) in the
insulation system from the dissipated signal.  Dissipation factor (loss) is
generally defined as a ratio of the energy dissipated to the energy stored in
the dielectric per unit Hz, or as the tangent of the loss angle.  For
dissipation factors less than 0.1, the dissipation factor may be considered
equal to the power factor of the dielectric, which is the cosine of the phase
angle by which the signal's current leads voltage.

A classic application for "dissipation loss" would be your microwave oven, if
you were trying to couple a microwave signal to your transmitting antenna
through your microwave oven (with food stuff), most of your signal would be
dissipated in the oven and not get to the antenna.  The same holds true for
printed board and other dielectrics, the goal (generally) is to have the
in/out signal to have 100 percent coupling through the interconnection
network, and not absorbed in the dielectric.  With "high power" signals
(transmitters),  a "high loss" dissipative factor material could result in a
fire (called advanced dielectric heating).  In the case of very weak
electrical signals or signals needing high signal integrity, you want low loss
materials.  As a rule of thumb, many of the lower loss materials have low
molecular weight, such as polyethylene, propylene, styrene, and one of the
frequently used printed board "high frequency" base materials -- teflon.

Hope this helps,

Ralph Hersey
[log in to unmask]      

--------------------------------------
Date: 8/28/96 9:13 AM
From: [log in to unmask]
     
     I am having trouble understanding what EXACTLY "dissipation loss" is 
     WRT laminates.
     
     Can someone please enlighten me?  What are the units, etc.?
     
     Enquiring minds want to know.
     
     Regards,
     
     John R. Kretsch, P.E.
     Sr. Engineer, Design Assurance
     [log in to unmask]

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