Leaf-Shaped Element Bowtie Antenna with Flat Reflector for UWB Applications

Michitaka AMEYA  Manabu YAMAMOTO  Toshio NOJIMA  Kiyohiko ITOH  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.9   pp.2230-2238
Publication Date: 2007/09/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.9.2230
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on 2006 International Symposium on Antennas and Propagation)
Category: Antennas
UWB,  bowtie-antenna,  unidirectional radiation,  waveform distortion,  cross-correlation,  

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Recently, a lot of UWB antennas have been reported by many research groups. Most of the reported antennas have omnidirectional radiation characteristics. The disadvantage of using omnidirectional antennas is that the antenna performance can be degraded by adjacent walls or metals. If unidirectional UWB antennas are utilized, the degradation on the antenna performance due to omnidirectionality can be avoided. Another important topic in UWB antennas is the waveform distortion caused by antennas' transmission characteristics. In impulse-based UWB communications, waveform distortions of transmitted and received pulses caused by antennas deteriorate the communication performance. Therefore, the development of UWB antennas having small waveform distortions is highly desirable. In this paper, we propose a novel bowtie antenna using leaf-shaped radiating elements and a flat reflector. This antenna has unidirectional radiation patterns over the frequency range of 3.0 to 10.5 GHz. The actual gain in the maximum radiation direction is 6.0-9.0 dBi in the frequency range of 4.5-9.4 GHz (relative bandwidth of 71%). The cross-correlations between source pulse and received pulse waveforms are 0.89-0.94, and hence the waveform distortion caused by this antenna is relatively small. As a result, the proposed antenna is useful for impulse-based UWB communication systems using correlation detection.