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tinkuraki
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Homework Statement
Metals do have negligible penetration depth at higher frequencies considering microwave and infrared range.so microwaves are reflected by metals.but it is observed that metal powders when compacted under pressure to a certain porosity level nearly 10 to 30% porosity,have penetration depth almost nearer to dielectric materials and they respond to microwaves.They are behaving similar to dielectrics,how can it happen in this case,is that metal powder compacts which has high resistivity? or any other reason ?Is there any dielectric polarisation and ionic polarisation arises in this case leading to it to act as dielectric?
2.Does higher penetration depth indicates it is developing eddy current losses/ohmic heating at microwave frequency?
Homework Equations
ePenetartion depth of metals is in order of micrometres
penetration depth of metal powder compacts is in order of centi metres at 2.45Ghz frequency