Experimental Study of UWB Impulse Response and Time Reversal Communication Technique up to 12 GHz

In this study, we present an experimental study of the time reversal (TR) technique in a single-input single-output configuration over the frequency range of 2-12 GHz. Our TR implementation is demonstrated to have high accuracy by comparing experimental TR traces with theoretical traces computed from the measured channel response. A special emphasis of this work is to investigate the effectiveness of TR in typical line-of-sight (LOS) and non-line-of-sight (NLOS) indoor environments for omni-directional antennas. We discuss the effects of the channel multipath dispersion on the received responses in both time and frequency domains. "RMS delay spread" and "peak-to-average power ratio" are calculated as two basic parameters for impulse response and TR performance evaluations. Our study suggests that the effectiveness of TR is subject to a trade-off between competing effects - namely, compensation of spectral phase variation (which leads to compression) and aggravation of spectral amplitude structure (which opposes compression). TR appears to mitigate multipath dispersion in NLOS channels to a modest extent. However, in LOS scenarios the effectiveness of TR in compressing time spread associated with multipath delay appears to be very limited.