UWB Antenna Calculator

Overview

The UWB Antenna Calculator computes the key frequency-domain parameters of an Ultra-Wideband (UWB) antenna system from a center frequency and bandwidth. Enter a center frequency in GHz (such as 6.5 GHz for the common UWB mid-band or 3.9–4.5 GHz for one of the FCC-defined UWB sub-bands) along with the desired bandwidth, and the calculator returns the lower and upper edge frequencies, wavelength at each edge and center, fractional bandwidth, and whether the resulting signal qualifies as UWB under the standard 20% fractional-bandwidth or 500 MHz absolute-bandwidth rule. This is useful for RF engineers, antenna designers, and researchers working on impulse radio, indoor positioning (RTLS), radar, and short-range high-data-rate wireless links where a very wide operating bandwidth — not a single resonant frequency — defines the design.

Input Guide

Enter Center Frequency exactly as shown on the calculator. Confirm every unit, selected option, and decimal position before calculating so the uwb antenna result matches the intended wireless communication design case.

Output Guide

The output section reports Lower Frequency, Centre Frequency, Upper Frequency, Wavelength at Lower Frequency, Centre Wavelength, Wavelength at Upper Frequency, Fractional Bandwidth, Absolute Bandwidth, FCC UWB Classification, Design Note for the values you entered. Use these values as design targets, then compare them with available space, component limits, feed system behavior, installation environment, and measured performance before finalizing the design.

How This Calculator Works

The UWB Antenna applies fL = fc − BW/2 | fH = fc + BW/2 | lambda = c/f | FBW = BW/fc ×100 to the entered values. Calculate Ultra-Wideband (UWB) antenna parameters including lower frequency, upper frequency, wavelength range, fractional bandwidth, and FCC UWB compliance. Use the result as a first-pass wireless communication target, then validate it against losses, tolerances, mounting, nearby conductors, feed-line effects, and measurement conditions.

Design Notes

Unlike narrowband antennas designed around a single wavelength, UWB antennas must maintain acceptable impedance matching and radiation performance across an entire band that can span several GHz, which is why fractional bandwidth (FBW = BW/fc × 100%) is the defining metric rather than a single lambda/4 or lambda/2 dimension. A signal qualifies as UWB per the FCC definition if its fractional bandwidth is at least 20% or its absolute bandwidth is at least 500 MHz, whichever criterion is met first — both are checked automatically by this calculator. Because the physical antenna must radiate efficiently at the lower edge frequency (where wavelength is longest, driving minimum size) while maintaining performance at the upper edge frequency (where dimensional tolerances and higher-order modes become critical), UWB designs like Vivaldi, bowtie, monopole disc, and planar horn antennas are typically sized around the lower-band wavelength and then refined through simulation across the full band.

Build and Tuning Notes

Use the calculated lower, center, and upper frequencies as the target operating band for full-wave electromagnetic simulation (HFSS, CST, or openEMS) rather than a direct cut-to-length dimension, since UWB antenna geometry — substrate dielectric constant, ground plane shape, feed transition, and enclosure — has a much larger effect on bandwidth and return loss than in narrowband designs. Once a prototype is built, verify performance with a vector network analyzer (VNA) across the full lower-to-upper frequency range, checking that S11 stays below -10 dB (or your target threshold) throughout the band, not just at the center frequency, since many UWB designs pass at fc but degrade sharply near the band edges. Also confirm regulatory compliance (FCC Part 15 in the US, or the applicable regional UWB mask) for both the frequency range and radiated power spectral density, since qualifying as UWB by bandwidth alone does not guarantee compliance with emission limits.