Elena Pancera

A novel approach to OFDM radar processing

In this paper a novel approach for the calculation of the radar range profile in OFDM radar systems is presented. The proposed algorithm operates directly on the modulation symbols and overcomes the typical drawbacks of correlation based baseband signal processing. An example system configuration as well as simulation results from a dedicated MatLab model will be presented and discussed.

Spherical Fidelity Patterns of UWB Antennas

The time domain radiation properties of UWB antennas are analyzed, especially the angular dependent impulse distortion, with respect to the signal transmitted in the main beam direction, is investigated. The correlation properties of the radiated pulses are determined by the so called fidelity F. The fidelity F is together with the peak pulse amplitude P a powerful tool for the characterization of impulse radiating antennas. The results are applied to two different UWB antennas, a Vivaldi antenna and a Bow-tie antenna. The spatial regions with good correlation and high peak power are determined for both by measurements for verification. The results are vital for UWB impulse communications, and for UWB Radar as well.

Medical applications of the Ultra Wideband technology

In this paper the application of the Ultra Wideband technology in the medical field is investigated. This is done by presenting a mathematical description of the Ultra Wideband medical scenario and a model of the human body. Besides, the requirements of antennas for Ultra Wideband medical applications are discussed. The most important existing applications of the UWB technology in the medical field are shown and discussed.

UWB synthetic aperture-based radar system for hemorrhagic head-stroke detection

In this paper, a synthetic aperture based ultra wideband imaging system with semi-adaptive signal processing is proposed for hemorrhagic stroke detection in a simulated head model. The 3D spherical model consists of four dispersive layers representing different parts of the head. In a bistatic configuration, two ultra wideband Vivaldi antennas sweep a semi-spherical synthetic array conformal to the model. As for image reconstruction algorithm, conventional delay and sum together with coherence weighting is applied to the backscattered signals. Through achieved simulation results, it is shown that ultra wideband radar concept has the potential of being an alternative imaging technique for stroke detection.

Correlation properties of the pulse transmitted by UWB antennas

In this paper the radiation properties of UWB antennas in the time domain are analyzed. In particular, the distortion that the transmitted signal undergoes in different angular directions with respect to the signal transmitted in the main beam direction is investigated. This study is accomplished by an analysis of the correlation properties of the angular dependent antenna transient response. Results are shown for the Vivaldi and the Bow-tie antennas.

Ultra wideband radar imaging: An approach to monitor the water accumulation in the human body

In this paper the applicability of UWB technology in the medical field is analyzed. In particular, a method for the monitoring of water accumulation in the human body is presented, which permits through UWB medical imaging to estimate the quantity of urine in the bladder.

Fidelity based optimization of UWB antenna-radiation for medical applications

In this paper an optimization technique for the radiation properties of UWB antennas for medical applications is presented. The method is based on the fidelity characterization parameter and it is performed in the time domain, taking into consideration the frequency-dependent dielectric properties of the human body as transmission layer.

Correlation properties of UWB Radar target impulse responses

In this paper the time domain responses of UWB Radar signals from scattering targets are analyzed. In particular, the aim of this paper is to investigate the pulse distortion of UWB Radar signals by a scattering object, i.e. how does the scattered signal vary with respect to the Radar signal incident on the object itself. The investigation is performed analyzing the polarimetric responses of different targets (flat plate, sphere). The time domain description (impulse response and pulse preserving capability) of a generic scattering process is mathematically described. Then for verification and application, these prior defined quantities are experimentally measured for two particular targets, a flat plate and a sphere.

Estimated performance of UWB impulse radio transmission including dirty RF effects

For studying the performance of an ultra-wideband (UWB) system, either measurements or simulations can be performed. Simulations for performance predictions are more flexible, but they require an accurate system modeling that takes into account the non-ideal hardware. This paper presents the UWB indoor channel modeling, including relevant, non-ideal hardware components for the UWB impulse radio technique. As a performance measure the estimated bit error rate versus distance and versus signal-to-noise ratio for Time Hopping Pulse Position Modulation (TH-PPM) in a line of sight indoor scenario is presented. The influence of the data rate on the bit error rate is investigated as well.

Impact of the UWB Filter Frequency Domain Non-Idealities on the Filter Transient Response

In this article an approach to the characterization of the behavior of UWB filters in the time domain is presented. In particular, the relationship between the filter frequency domain non-idealities (such as variations of the filter group delay time and ripple in the frequency mask) and their effect on the corresponding filter time domain behavior (transient response) are analyzed. In a novel approach the distortion introduced by a filter with a randomly generated group delay and filter frequency mask are investigated. It is discovered that there is a relatively sharp bound on values of the standard deviation of the filter group delay time and standard deviation of the ripple in the frequency filter mask below which the distortion in the time domain is negligible. The parameters are focused on UWB filters for the European UWB regulations operating in the 6-8.5 GHz frequency range. Index Terms – UWB, Filters, Non-Idealities, Group Delay Time, Ripple, Time Domain.