# Dielectric Resonators, Resonant Frequency, and Dielectric Constant?

HMS-776
Hello,

I have been trying to better understand the effects of dielectrics in resonant cavities.

I read that the addition of a dielectric in a resonant cavity will reduce the resonant frequency of the cavity.

My questions:

Is there any relation to the reduction of the resonant frequency and the dielectric constant of the dielectric placed in a resonant cavity?

Would it be possible to build a small resoant cavity (less than 1 foot in volume) which had a resonant frequency in the audio range by adding a dielectric to it?

Gold Member
Yes, a dielectric will reduce the resonant frequency of a cavity. If the dielectric fills the cavity, then the frequency is reduced by approximately the square root of the dielectric constant.

No, you can't build a small cavity that resonates at audio because at least one dimension of the cavity must be wavelength/2. The wavelength of a 1 kHz wave is 3x10^5 m or 3,000 km--about the width of the United States. Filling it with water, which has about the highest dielectric constant (81) of any ordinary material, drops the physical dimensions by 9, to about 2,000 km. Still big compared to one foot...

hamza_1980
i need problems and solutions about dielectric material