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What makes an antenna suitable for UWB?

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An ultra-wideband antenna must keep impedance match, pattern and phase center stable over at least 500 MHz (or 20% fractional bandwidth) so that short pulses are radiated without distortion. In the US, UWB devices are regulated under Part 15 Subpart F, with average EIRP limited to −41.3 dBm/MHz in the 3.1–10.6 GHz band for many device classes;[1] IEEE 802.15.4z ranging commonly uses channels 5 (6.5 GHz) and 9 (8 GHz) of about 500 MHz bandwidth.[2]

Which antennas are used for UWB?

Planar elliptical and circular disc monopoles, bow-ties, tapered-slot Vivaldis, small horns and compact printed monopoles for consumer devices. Schantz emphasizes that UWB antennas should be evaluated in the time domain as well as frequency domain.[3]

What is pulse fidelity?

Fidelity is the peak normalized cross-correlation between the radiated (or received) pulse and a reference waveform. Antennas with frequency-dependent phase center or resonances (e.g., log-periodics, spirals) disperse pulses, harming ranging accuracy, while small electric monopoles and Vivaldis tend to preserve pulse shape.[3]

How does UWB measure angle of arrival?

Two or three antennas spaced about λ/2 apart measure phase difference of arrival (PDoA); the angle follows from Δφ = 2πd·sinθ/λ. Antenna phase-center stability and mutual coupling directly affect angle accuracy, so the antennas are calibrated per device.[2][4]

Frequently asked questions

What is UWB used for?

Precise ranging and positioning, digital car keys, item finders and secure access.

Is UWB interference to other systems a concern?

Low power spectral density limits interference; regulators set strict masks.

Do UWB antennas need to be large?

No; at 6–9 GHz printed monopoles of a centimeter or so are common.

References

Online sources accessed October 21, 2026; printed works cited by edition. See all sources.

  1. “47 CFR Part 15 Subpart F — Ultra-Wideband Operation”. U.S. FCC, eCFR. current text.
  2. “IEEE Std 802.15.4z-2020: Enhanced Ultra Wideband (UWB) Physical Layers and Associated Ranging Techniques”. IEEE. 2020.
  3. “The Art and Science of Ultrawideband Antennas”. H. G. Schantz, Artech House. 2005.
  4. “Foundations of MIMO Communication”. R. W. Heath Jr. and A. Lozano, Cambridge University Press. 2018.
Categories: Applications by band