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I had the same thoughts and had the occasion to measure a IVP under construction and as I recall the value was about 5 ohms which makes it to be about 5 ohms/square. So against a nominal 50 ohms at the feed point, maybe 10% loss, which is not the worst thing in the world. Therefore I would essentially think of carbon composite sheets as metal sheets and design accordingly. I.e., if the antenna is inside a carbon shell, it won't work well, if outside it will, the same as in a traditional aluminum construction. Because of windows, cracks (seams at the door), etc., there is leakage from the inside of a aluminum plane, but it will be very directional and likely to be very poor for ground communication signals. My two cents worth. (A further sidebar. Since carbon fiber it is a measurable 5 ohms, it will not shield as well as aluminum, therefore there will be significant leakage in comparison to aluminum I.e. up close it might appear that you can transmit/receive from antennas inside, but I would estimate that the attenuation is on the order of 20 dB or more.)
Charles Patton
Paul Lipps wrote:
Jim Cameron,
Putting the antenna on the outside of a carbon plane is almost as bad as putting it on the inside. Being a carbon conductor (think resistor), it will absorb most of the power put into the antenna, especially if its impedance appears similar to free-space impedance.
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