The Don Smith Effect

Hello Fighter,

Desperately waiting for updates...

Keep the existing Teflon, or remove it if you think that would work better. Could you add pieces of plastic sheet between the plates in your current design?

Plastics worth considering -

Teflon (PTFE): Excellent dielectric properties, very low high-frequency losses, and high temperature and voltage resistance. It seems particularly suitable for RF applications.

Polypropylene (PP): Very low dielectric losses, good capacitance stability, and relatively low heating under RF conditions. This appears to be another strong option for high-frequency use.

Polycarbonate (PC): Good dimensional stability and relatively low electrical losses, which can be useful where consistent capacitance is important.

Polystyrene (PS): Known for very low dielectric losses, although it has a lower temperature limit than PTFE.

Polyester (PET / Mylar): Commonly used in film capacitors because of its good dielectric strength and mechanical durability. It generally has somewhat higher losses than PP or PTFE, but may be easier and cheaper to obtain.

Materials I would avoid -
PVC (Polyvinyl Chloride): Relatively high dielectric losses compared with the materials above, which can make it less suitable for RF/high-frequency applications.

Cellulose acetate: Also has comparatively higher losses and may not be ideal for RF applications.

Regards WC