Cavity Resonance Frequency Calculator

Enter dimensions of the microwave cavity, mode number, dielectric constant and magnetic permeability to calculate the cut off frequency of the cavity.

Calculate the Cut-off Frequency of the Cavity


  • Cut-off Frequency
Formula for Cavity Resonance Frequency Calculator

What is the resonant frequency of a cavity?

The cavity resonator has hollow space with metallic walls enclosing it. The dimension of the resonant cavity is similar to or larger than the operating wavelength. Resonant cavities are exclusively operated at microwave frequencies i.e., 300 MHz to 30 GHz where wavelengths are of 1 cm to 1 m. The walls of the resonant cavity are adjusted for obtaining the required frequency. The electromagnetic fields inside the resonant cavity are energized by an external power supply. 

These resonant cavities with their optimum resonant frequencies have many applications in microwave circuits like transmitters, receivers, and test equipment. Acoustic resonant cavities are also used for making musical instruments.

How to calculate the resonant frequency of a cavity?

The resonant frequency of a cavity can be calculated by using the following formula.


c = Light speed

 εr = Dielectric constant

µr = Magnetic permeability

a, b, h = Cavity width, length, height in mm/cm/Inch

m,n,p = Mode number (should not be 0)

If a<b<h then the lowest response frequency is c/2a

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