A Critical Look at the Principles of Electromagnetic Time Reversal and its Consequences

A plethora of papers can be found in the scientific literature talking about time reversal. The term time reversal exists in the publications in a variety of different fields, such as ultrasonics, acoustics, wireless communications, electromagnetics, antennas and propagation, optics, physics, and philosophy. The term time reversal by itself sounds very interesting, and can provide many interpretations that are fascinating. However, due to a loose use of this term, it may in many cases lead to fallacious interpretations and conclusions if it is not interpreted in strict scientific terms. The main goal of this paper is to explain the appropriate definition of the term time reversal in electrical engineering in general, and in electromagnetics for wireless communications, to be specific. However, the motivation of the work presented in this paper is not to raise a controversy about time reversal and its related research. Rather, the aim of this work is to highlight the basic electrical engineering fundamentals that are necessary to study time reversal and to correctly define it, and to then accordingly interpret the results. Hence, the true and fallacious benefits of electromagnetic time reversal will be exposed. To serve this purpose, the paper is divided into two parts. First, a detailed literature review is presented. The true history of the term time reversal in electrical engineering is traced. In this part, most of the reported definitions of time reversal and its claimed capabilities are summarized. Some problems with the application of time reversal in electromagnetics are discussed, both theoretically and practically. All of the time-reversal papers talk about reciprocal networks, so the fact of the non-reciprocity of a single-antenna system in the time domain (the way we generally interpret it) is presented, to prove theoretically that there is a problem with how we interpret time reversal in electromagnetics. Finally, practical examples are shown, where time reversal is used in a wireless system and in an acoustic de-reverberation problem. The exact capabilities of time reversal in electrical engineering are exposed in those experiments.

[1]  M.C. Wicks,et al.  Transmission and Reception by Ultra-Wideband (UWB) Antennas , 2006, IEEE Antennas and Propagation Magazine.

[2]  M.C. Wicks.  Century bandwidth antennas for use in applications with waveform diversity , 2008, 2008 IEEE Antennas and Propagation Society International Symposium.

[3]  P. Kosmas,et al.  A matched-filter FDTD-based time reversal approach for microwave breast cancer detection , 2006, IEEE Transactions on Antennas and Propagation.

[4]  G. Lerosey,et al.  Time reversal of wideband microwaves , 2006 .

[5]  José M. F. Moura,et al.  Detection by Time Reversal: Single Antenna , 2007, IEEE Transactions on Signal Processing.

[6]  J. Kormylo,et al.  Two-pass recursive digital filter with zero phase shift , 1974 .

[7]  P. Kosmas,et al.  FDTD-based time reversal for microwave breast cancer Detection-localization in three dimensions , 2006, IEEE Transactions on Microwave Theory and Techniques.

[8]  Layane Abboud,et al.  Effectiveness of Time-Reversal technique for UWB wireless communications in standard indoor environments , 2010, 2010 Conference Proceedings ICECom, 20th International Conference on Applied Electromagnetics and Communications.

[9]  K. J. Ray Liu,et al.  Green Wireless Communications: A Time-Reversal Paradigm , 2011, IEEE Journal on Selected Areas in Communications.

[10]  Andrea Cozza.  Statistics of the performance of time reversal in a lossy reverberating medium. , 2009, Physical review. E, Statistical, nonlinear, and soft matter physics.

[11]  Mathias Fink,et al.  Time Reversal of Ultrasonic Fields-Part 11: Experimental Results , 1992 .

[12]  Panagiotis Kosmas,et al.  A Computational Study of Time Reversal Techniques for Ultra-Wideband Microwave Hyperthermia Treatment of Breast Cancer , 2007, 2007 IEEE/SP 14th Workshop on Statistical Signal Processing.

[13]  P. Pagani,et al.  On the Use of Uniform Circular Arrays for Characterizing UWB Time Reversal , 2009, IEEE Transactions on Antennas and Propagation.

[14]  Richard D. Gitlin,et al.  Ghost cancellation of analog TV signals: with applications to IDTV, EDTV, and HDTV , 1991, IEEE Trans. Circuits Syst. Video Technol..

[15]  Hung Tuan Nguyen,et al.  Time reversal in wireless communications: a measurement-based investigation , 2006, IEEE Transactions on Wireless Communications.

[16]  Dinh Thuy Phan Huy,et al.  Time reversal outage probability for wideband indoor wireless communications , 2010, 21st Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications.

[17]  Kyritsi,et al.  MISO time reversal and delay-spread compression for FWA channels at 5 GHz , 2004, IEEE Antennas and Wireless Propagation Letters.

[18]  Hung Tuan Nguyen.  On the performance of one bit time reversal for multi-user wireless communications , 2007, 2007 4th International Symposium on Wireless Communication Systems.

[19]  P. Kyritsi,et al.  Time reversal techniques for wireless communications , 2004, IEEE 60th Vehicular Technology Conference, 2004. VTC2004-Fall. 2004.

[20]  A.D. Kim,et al.  Spatial Focusing and Intersymbol Interference in Multiple-Input–Single-Output Time Reversal Communication Systems , 2008, IEEE Journal of Oceanic Engineering.

[21]  L Sevgi,et al.  Reciprocity: Some Remarks from a Field Point of View , 2010, IEEE Antennas and Propagation Magazine.

[22]  A. Fam,et al.  Efficient linear phase filters based on switching and time reversal , 1990, IEEE International Symposium on Circuits and Systems.

[23]  P. Kosmas,et al.  Time reversal with the FDTD method for microwave breast cancer detection , 2005, IEEE Transactions on Microwave Theory and Techniques.

[24]  Gang Kang,et al.  Electromagnetic time-reversal imaging of a target in a cluttered environment , 2005, IEEE Transactions on Antennas and Propagation.

[25]  Hung Tuan Nguyen,et al.  The potential use of time reversal techniques in multiple element antenna systems , 2005, IEEE Communications Letters.

[26]  Andrea Cozza,et al.  Enforcing deterministic polarisation in a reverberating environment , 2009 .

[27]  A.J. Paulraj,et al.  Characterization of space-time focusing in time-reversed random fields , 2005, IEEE Transactions on Antennas and Propagation.

[28]  J.-Y. Dauvignac,et al.  Real data microwave imaging and time reversal , 2007, 2007 IEEE Antennas and Propagation Society International Symposium.

[29]  Andrea Cozza,et al.  Experimental analysis of the performance of a time-reversal electromagnetic chamber , 2010, 2010 Asia-Pacific International Symposium on Electromagnetic Compatibility.

[30]  A. B. Ruffin,et al.  Time reversal and object reconstruction , 2000 .

[31]  Andrea Cozza.  Increasing peak-field generation efficiency of reverberation chamber , 2010 .

[32]  Hung Tuan Nguyen,et al.  A Time Reversal Transmission Approach for Multiuser UWB Communications , 2006, IEEE Transactions on Antennas and Propagation.

[33]  Alan V. Oppenheim,et al.  Television signal deghosting by noncausal recursive filtering , 1988, ICASSP-88., International Conference on Acoustics, Speech, and Signal Processing.

[34]  K. S. Yeung,et al.  Implementing unstable filters via input signal reversal-a state variable perspective , 1998 .

[35]  Peter Vary,et al.  A binaural room impulse response database for the evaluation of dereverberation algorithms , 2009, 2009 16th International Conference on Digital Signal Processing.

[36]  Time reversal and object reconstruction using single-cycle terahertz pulses , 2000, LEOS 2000. 2000 IEEE Annual Meeting Conference Proceedings. 13th Annual Meeting. IEEE Lasers and Electro-Optics Society 2000 Annual Meeting (Cat. No.00CH37080).

[37]  Ali Khaleghi.  Measurement and Analysis of Ultra-Wideband Time Reversal for Indoor Propagation Channels , 2010, Wirel. Pers. Commun..

[38]  Arogyaswami Paulraj,et al.  Experimental Investigation on Time Reversal Precoding for Space–Time Focusing in Wireless Communications , 2010, IEEE Transactions on Instrumentation and Measurement.

[39]  T.K. Sarkar,et al.  Interpolation/extrapolation of frequency domain responses using the Hilbert transform , 1995, Proceedings of ISSE'95 - International Symposium on Signals, Systems and Electronics.

[40]  L. Carin,et al.  Electromagnetic Time-Reversal Source Localization in Changing Media: Experiment and Analysis , 2007, IEEE Transactions on Antennas and Propagation.

[41]  Francois Horlin,et al.  Performance evaluation of time reversal in intra-vehicular environment , 2011, Proceedings of the 5th European Conference on Antennas and Propagation (EUCAP).

[42]  Marc Heddebaut,et al.  Time-Reversal UWB Wireless Communication-Based Train Control in Tunnel , 2009, J. Commun..

[43]  G. Lerosey,et al.  Time reversal of electromagnetic waves. , 2004, Physical review letters.

[44]  M. Fink,et al.  Time Reversal of Ultrasonic Fields-Part I : Basic Principles , 2000 .

[45]  Po-Chuan Hsieh,et al.  Subwavelength Target Detection Using Ultrawideband Time-Reversal Techniques With a Multilayered Dielectric Slab , 2009, IEEE Antennas and Wireless Propagation Letters.

[46]  Mathias Fink,et al.  Time-Reversal of Ultrasonic Fields-Part 111: Theory of the Closed Time-Reversal Cavitv J , 1992 .

[47]  Bernard Widrow,et al.  Adaptive Inverse Control: A Signal Processing Approach , 2007 .

[48]  G. Lerosey,et al.  Theory of Electromagnetic Time-Reversal Mirrors , 2010, IEEE Transactions on Antennas and Propagation.

[49]  Yi Jiang,et al.  Time Reversal Beamforming for Microwave Breast Cancer Detection , 2007, 2007 IEEE International Conference on Image Processing.

[50]  Zhengqing Yun,et al.  Time reversal with single antenna systems in indoor multipath environments: spatial focusing and time compression , 2006, 2006 IEEE Antennas and Propagation Society International Symposium.

[51]  R. Czarnach.  Recursive processing by noncausal digital filters , 1982 .

[52]  George Papanicolaou,et al.  One-bit Time Reversal for WLAN Applications , 2005, 2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications.

[53]  Andrea Cozza,et al.  Directive wavefronts inside a time reversal electromagnetic chamber , 2009, 2009 IEEE International Symposium on Electromagnetic Compatibility.

[54]  B. Bogert.  Demonstration of Delay Distortion Correction by Time-Reversal Techniques , 1957 .