# fractional bandwidth (FBW)

The dimensionless characteristic value Fractional Bandwidth (FBW) is used to determine a relative bandwidth. This is the bandwidth of a filter, antenna

or electronic circuit, related to its center frequency. The fractional bandwidth can only assume values between 0 and 2, in percentages this corresponds to 0 % to 200 %. For example, if a bandpass has a bandwidth of 1 MHz and a center frequency of 10 MHz, then the ratio results in a Fractional Bandwidth of 0.1 or 10 %. The larger the FBW value, the wider the bandwidth of the corresponding electronic components.