Cavity Filter Design Calculator

Resonant Frequency Formula:

\[ f = \frac{c}{2} \times \sqrt{ \left(\frac{m}{a}\right)^2 + \left(\frac{n}{b}\right)^2 + \left(\frac{p}{d}\right)^2 } \]

Speed of Light (c):

m/s

Mode Number (m):

unitless

Mode Number (n):

unitless

Mode Number (p):

unitless

Cavity Length (a):

Cavity Width (b):

Cavity Height (d):

Resonant Frequency (f):

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1. What is a Cavity Filter Design Calculator?

Definition: This calculator determines the resonant frequency of a rectangular cavity resonator based on its dimensions and mode numbers.

Purpose: It helps RF engineers and filter designers calculate the fundamental resonant frequency for cavity filter applications.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ f = \frac{c}{2} \times \sqrt{ \left(\frac{m}{a}\right)^2 + \left(\frac{n}{b}\right)^2 + \left(\frac{p}{d}\right)^2 } \]

Where:

\( f \) — Resonant frequency (Hz)
\( c \) — Speed of light (299,792,458 m/s by default)
\( m, n, p \) — Mode numbers (unitless integers)
\( a, b, d \) — Cavity dimensions (length, width, height in meters)

Explanation: The formula calculates the frequency at which electromagnetic waves resonate within a rectangular cavity based on its physical dimensions and the selected mode of operation.

3. Importance of Cavity Resonator Calculation

Details: Accurate frequency calculation is essential for designing filters, waveguides, and other RF components in communication systems, radar, and microwave applications.

4. Using the Calculator

Tips: Enter the speed of light (default 299792458 m/s), mode numbers (typically integers), and cavity dimensions in meters. All dimension values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What are typical mode numbers?
A: For fundamental mode, use m=1, n=1, p=0 (TE101 mode). Higher integers for higher-order modes.

Q2: Can I use different units for dimensions?
A: The calculator expects meters. Convert other units to meters before input.

Q3: What if my cavity isn't rectangular?
A: This calculator is for rectangular cavities only. Cylindrical cavities require a different formula.

Q4: Why is p often set to 0?
A: p=0 represents the simplest TE mode where there's no variation in the height dimension.

Q5: How accurate is this calculation?
A: It provides theoretical values. Actual frequencies may vary due to manufacturing tolerances and material properties.