Question on Permittivity

[johnnykhor]

I have tried a few substrate with different relative permittivity, and now i have one question about it.

Does relative permittivity affect our design? (other than dimension)
is higher relative permittivity can give us better performance?
and lastly, is there any standard/rules on which relative permittivity is suitable for filter or antenna or power divider??

thanks in advance!!

 

[iyami]

The permittivity of a medium changes the wavelength for a each frequency (the higher the permittivity the shorter the wavelength). That means of course that resonances occur at different frequencies etc. So the answers to your questions are:

I have tried a few substrate with different relative permittivity, and now i have one question about it.

Does relative permittivity affect our design? (other than dimension)

Yes.

is higher relative permittivity can give us better performance?

Not necessarily.

and lastly, is there any standard/rules on which relative permittivity is suitable for filter or antenna or power divider??
thanks in advance!!

Not that I know.

 

[johnnykhor]

Thanks for your reply.
Now i am more confidence on what am i doing.

 

[MobiNaz]

Read Belanis, 'Antenna Theory' introduction of patch antennas chapter if you want to get an idea of how to select permittivity of material for antennas. It briefly talks/explains its importance in designing analog circuits.