Theory of electroporation: A review

When, in addition to the constant Doppler frequency shift induced by the bulk motion of a radar target, the target or any structure on the target undergoes micro-motion dynamics, such as mechanical vibrations or rotations, the micro-motion dynamics induce Doppler modulations on the returned signal, referred to as the micro-Doppler effect. We introduce the micro-Doppler phenomenon in radar, develop a model of Doppler modulations, derive formulas of micro-Doppler induced by targets with vibration, rotation, tumbling and coning motions, and verify them by simulation studies, analyze time-varying micro-Doppler features using high-resolution time-frequency transforms, and demonstrate the micro-Doppler effect observed in real radar data.

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Micro-Doppler effect in radar: phenomenon, model, and simulation study

Starting from Tesla's principles of wireless power transfer a century ago, this critical review outlines recent magneto-inductive research activities on wireless power transfer with the transmission distance greater than the transmitter coil dimension. It summarizes the operating principles of a range of wireless power research into 1) the maximum power transfer and 2) the maximum energy efficiency principles. The differences and the implications of these two approaches are explained in terms of their energy efficiency and transmission distance capabilities. The differences between the system energy efficiency and the transmission efficiency are also highlighted. The review covers the two-coil systems, the four-coil systems, the systems with relay resonators and the wireless domino-resonator systems. Related issues including human exposure issues and reduction of winding resistance are also addressed. The review suggests that the use of the maximum energy efficiency principle in the two-coil systems is suitable for short-range rather than mid-range applications, the use of the maximum power transfer principle in the four-coil systems is good for maximizing the transmission distance, but is under a restricted system energy efficiency (<;50%); the use of the maximum energy efficiency principle in relay or domino systems may offer a good compromise for good system energy efficiency and transmission distance on the condition that relay resonators can be placed between the power source and the load.

A Critical Review of Recent Progress in Mid-Range Wireless Power Transfer

This paper presents WiSee, a novel gesture recognition system that leverages wireless signals (e.g., Wi-Fi) to enable whole-home sensing and recognition of human gestures. Since wireless signals do not require line-of-sight and can traverse through walls, WiSee can enable whole-home gesture recognition using few wireless sources. Further, it achieves this goal without requiring instrumentation of the human body with sensing devices. We implement a proof-of-concept prototype of WiSee using USRP-N210s and evaluate it in both an office environment and a two- bedroom apartment. Our results show that WiSee can identify and classify a set of nine gestures with an average accuracy of 94%.

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Whole-home gesture recognition using wireless signals

Multiple-input-multiple-output (MIMO) wireless systems use multiple antenna elements at transmit and receive to offer improved capacity over single antenna topologies in multipath channels In such systems, the antenna properties as well as the multipath channel characteristics play a key role in determining communication performance This paper reviews recent research findings concerning antennas and propagation in MIMO systems Issues considered include channel capacity computation, channel measurement and modeling approaches, and the impact of antenna element properties and array configuration on system performance Throughout the discussion, outstanding research questions in these areas are highlighted

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A review of antennas and propagation for MIMO wireless communications

Wave propagation mechanisms in a lossy dielectric rod array are examined using full-wave simulation and homogenization theory. Both approaches show that a slab mode and an air mode propagate in the structure with different phase velocities. The propagation constants, attenuation constants, and field distributions of these two dominant mechanisms are extracted from simulation data and compared to those found from homogenization theory.

On Wave Propagation Mechanisms in a Dielectric Rod Array

Interpretation of Scattering Phenomenology Structures in Slotted Waveguide via Time-Frequency Processing

A random-phase-assisted ray-tracing technique for wireless channel modeling

A method is proposed that uses compressed sensing to obtain high-resolution radar images through a pipe. The method is demonstrated with simulation and measurement data and found to provide superior resolution in comparison to a matched filter.

Compressed sensing through a pipe

We carry out a phenomenological study of scattering from dielectric-coated wires. The scattering data are collected by both numerical simulation and by chamber measurement. The short-time Fourier transform (STFT) technique is used to extract the pertinent scattering physics of the structure. The surface wave, or the so-called the Goubau mode, is excited due to the dielectric coating around the wire. The features of this mode are studied and an interpretation of the dispersive behavior is given in the joint time-frequency plane with the help of the STFT technique. One way to gain better resolution in the joint time-frequency plane is with the Wigner-Ville distribution (WVD). However, it is well known that cross-term interference occurs between any pair of auto-terms in the joint-time frequency plane. To suppress the cross terms in the WVD, the time-frequency distribution series (TFDS) which takes the WVD of the Gabor expansion of the original signal is implemented. By keeping only the lower order terms in the series, a good compromise between resolution and cross term interference can be achieved.

http://ieeexplore.ieee.org/iel3/3857/11270/00549677.pdf

Hao Ling

Papers

On Wave Propagation Mechanisms in a Dielectric Rod Array

Interpretation of Scattering Phenomenology Structures in Slotted Waveguide via Time-Frequency Processing

A random-phase-assisted ray-tracing technique for wireless channel modeling

Compressed sensing through a pipe

Interpretation of scattering phenomenology in dielectric-coated wire via joint time-frequency processing