Comparison of UWB Antennas Considering Pattern Variation With Frequency

  • Tharaka Dissanayake
  • Karu P. Esselle

The radiated waveform shape of a good UWB antenna should be the same in all directions of interest. This property is termed “waveform omni-directionality”. Such antennas can be characterized by a single normalized transfer function or impulse response, making system optimization, equivalent circuit modeling, propagation analysis and pulse shaping filter design much easier. Waveform omni-directionality is directly related to the antenna pattern stability with respect to frequency. It may not be feasible to realize UWB antennas with absolutely stable patterns; however, a quantitative figure for pattern stability enables one to compare UWB radiation from various antennas in a range of directions of interest. In this paper we use a newly proposed Pattern Stability Factor (PSF) to compare several probe-fed monopole UWB antennas and microstrip-fed printed planar monopole UWB antennas. The PSF is also used to determine the pattern stability bandwidth of those antennas. The PSF is defined in the frequency domain because UWB regulations (e.g. on bandwidth, mask level etc.) are specified in this domain but it also represents waveform fidelity and omni-directionality in the time domain. It is important to note that the PSF is independent of the gain of the antenna. For a good PSF, a flat gain response (versus frequency) is not necessary but the gain frequency response curves should be similar (apart for a constant) in all directions of interest. A pattern stable antenna fulfills this condition because, although its absolute gain pattern may change with frequency, the fractional change is the same in all directions of interest.


Ground Plane Return Loss Pattern Stability Mask Level Narrow Frequency Range 
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5. References

  1. 1.
    Stanley Bo-Ting Wang, Ali M. Niknejad and Robert W. Borderson, “Modeling Omnidirectional Small Antennas for UWB Applications”, IEEE Antenna and Propagation International Symposium, June (2004).Google Scholar
  2. 2.
    Florent Munier, Thomas Eriksson, and Arne Svensson. “On The Effect ofAntennas in UWB Systems”, In Proceedings of 28th URSI General Assembly in India (2005).Google Scholar
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    Goufeng Lu, and Larry Greenstien, “Antenna and Pulse Designs for Meting UWB Spectrum Density Requirements”, IEEE Conference on Ultra-wideband Systems and Technologies, November (2003).Google Scholar
  4. 4.
    T. Dissanayake, and Karu Esselle, “ A Printed Triangular-ring Antenna with a 2:1 Bandwidth”, Microwave and Optical Technology Letters, 44(1), (2005)Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Tharaka Dissanayake
    • 1
  • Karu P. Esselle
    • 1
  1. 1.Department of Electronics, School of Information and SciencesMacquarie UniversityAustralia

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