1. What is Fractional Bandwidth?

Fractional Bandwidth (FBW) is a measure of how wide a bandwidth is compared to its center frequency. It's a dimensionless quantity used in signal processing and antenna design to characterize the relative width of a frequency band.

2. How Does the Calculator Work?

The calculator uses the Fractional Bandwidth equation:

Where:

• \( FBW \) — Fractional Bandwidth (dimensionless)
• \( BW \) — Bandwidth (Hz)
• \( f_c \) — Center frequency (Hz)

Explanation: The equation calculates the ratio of the bandwidth to the center frequency, providing a relative measure of bandwidth width.

3. Importance of FBW Calculation

Details: Fractional Bandwidth is crucial in antenna design, filter characterization, and communication systems where the relative bandwidth affects performance and design parameters.

4. Using the Calculator

Tips: Enter bandwidth and center frequency in Hz. Both values must be positive numbers. The result is a dimensionless ratio.

5. Frequently Asked Questions (FAQ)

Q1: What is considered a wide fractional bandwidth?
A: Typically, FBW > 0.2 is considered wide bandwidth, while FBW < 0.01 is narrow bandwidth.

Q2: How is fractional bandwidth different from percentage bandwidth?
A: Percentage bandwidth is simply fractional bandwidth multiplied by 100. FBW = 0.1 means 10% bandwidth.

Q3: Why is fractional bandwidth important in antenna design?
A: Antenna performance characteristics like impedance matching and radiation pattern are strongly affected by fractional bandwidth.

Q4: Can fractional bandwidth be greater than 1?
A: Yes, when the bandwidth is larger than the center frequency (common in ultra-wideband systems).

Q5: How does fractional bandwidth relate to Q factor?
A: For narrowband systems, Q ≈ 1/FBW. The relationship becomes less accurate as FBW increases.