Experimental Investigation of UWB Impulse Response and Time Reversal Technique Up to 12 GHz: Omnidirectional and Directional Antennas

• Published in: IEEE transactions on antennas and propagation Vol. 60; no. 7; pp. 3407 - 3415
• Main Authors: Dezfooliyan, A., Weiner, A. M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.07.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna dispersion; Antenna measurements; Antennas; Applied sciences; channel propagation measurement; Channels; Compensation; Compressing; Delay; directional antenna; Directive antennas; Dispersion; Exact sciences and technology; Impulse response; multipath channel; omnidirectional antenna; Radiocommunications; Spectra; Spirals; Spreads; Studies; Telecommunications; Telecommunications and information theory; time reversal (TR); ultrawidebandwidth (UWB); Performance evaluation; Line of sight propagation; Time frequency domain method; Peak to average power ratio; Antenna dispersion; Broadband antennas; Multipath channels; channel propagation measurement; Indoor installation; Pulse response; Spectrum analysis; directional antenna; Delay time; Time reversal; ultrawidebandwidth (UWB); Non directive antenna; Dispersive channel; Non line of sight propagation; Multipath propagation; Phase distortion; Ultra wide band; Helical antenna; multipath channel; Directive antenna; omnidirectional antenna; SISO system; time reversal (TR); Signal analysis
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2012.2196927

An experimental study of the time reversal (TR) technique is presented in a single-input-single-output configuration over the frequency range of 2-12 GHz. A special emphasis of this work is to investigate and compare impulse response (IR) and TR characteristics for omnidirectional biconical and directional spiral antennas over realistic indoor ultrawideband (UWB) channels in both line-of-sight (LOS) and non-line-of-sight (NLOS) environments. We discuss the effects of channel multipath dispersion and antenna frequency-dependant delay distortions on the received responses in both time and frequency domains. The effectiveness of TR for waveform compression is characterized by computing root mean square delay spread and peak-to-average power ratio. Our study suggests that the effectiveness of time reversal is subject to a tradeoff between competing effects-namely, compensation of spectral phase variation (which leads to compression) and aggravation of spectral amplitude structure (which opposes compression). Although TR is a powerful technique for compensation of phase distortions associated with broadband frequency-independent antennas (as shown in LOS experiments with spiral antennas), it shows only modest performance in compressing time spread associated with multipath delays.