Greeting,
In the attachments that are the same you should find a short discussion on
the above named subject matter.
Richard
--- Begin Message ---
Recently there has been some very interesting discusions amoung several people
from our group. I will reference so as to be brief.
We measured a large number of conductive coatings on several plastics using
both far and near magnetic fields(see IEEE EMC Aug. 1994 Proceedings, p.224).
The relationship between shielding effectiveness(SE) at the far field and
magnetic and electric field was also done using an improved program(see
appendix of ASTM std for far field measurements in above ref).
Also we did accelerated testing at 65 C/ 85 % RH ( 5 year lifetime) and 85 C/
85 % RH( 25 year lifetime). For example, Silver plated copper metal filler in
conductive would withstand 25 year life in 2 mils. The surface resistance was
very high, outside the design range, but the SE was not changed. The design
rule that follows is that so long as the surface is covered so as to block th
availability of the Cu/oxygen reaction the system will withstand 25 years
lifetime.
We used the magnetic probes( like Cortland Richland, see e-mail 2/26) to
measure SE of gaskets and Ag loaded conductive paints. The probes were custom
designed to fit into a cellular phone housing(see Proceeding of the IEEE EMC,
1996, 407.) These experiments were done to show "how to" and there is also
detailed data on silver conductive paints.
A more detailed use of the magnetic probes, circular vs square, can be seen in
ITEM, p. 128, 1996.
If it will be heplful to any of our group I will supply what is necessary.
Needless to say as, with others, there is much more than I could type up in
this short amount of time.
Thanks
Richard Haynes
609-497-4584
P.S. My friend, Doug C. Smith, d.smith.usa.net , is better equipped to answer
questions of an electrical nature.
--- End Message ---
--- Begin Message ---
Recently there has been some very interesting discusions amoung several people
from our group. I will reference so as to be brief.
We measured a large number of conductive coatings on several plastics using
both far and near magnetic fields(see IEEE EMC Aug. 1994 Proceedings, p.224).
The relationship between shielding effectiveness(SE) at the far field and
magnetic and electric field was also done using an improved program(see
appendix of ASTM std for far field measurements in above ref).
Also we did accelerated testing at 65 C/ 85 % RH ( 5 year lifetime) and 85 C/
85 % RH( 25 year lifetime). For example, Silver plated copper metal filler in
conductive would withstand 25 year life in 2 mils. The surface resistance was
very high, outside the design range, but the SE was not changed. The design
rule that follows is that so long as the surface is covered so as to block th
availability of the Cu/oxygen reaction the system will withstand 25 years
lifetime.
We used the magnetic probes( like Cortland Richland, see e-mail 2/26) to
measure SE of gaskets and Ag loaded conductive paints. The probes were custom
designed to fit into a cellular phone housing(see Proceeding of the IEEE EMC,
1996, 407.) These experiments were done to show "how to" and there is also
detailed data on silver conductive paints.
A more detailed use of the magnetic probes, circular vs square, can be seen in
ITEM, p. 128, 1996.
If it will be heplful to any of our group I will supply what is necessary.
Needless to say as, with others, there is much more than I could type up in
this short amount of time.
Thanks
Richard Haynes
609-497-4584
P.S. My friend, Doug C. Smith, d.smith.usa.net , is better equipped to answer
questions of an electrical nature.
--- End Message ---
