نتایج جستجو برای: wideband uwb
تعداد نتایج: 13346 فیلتر نتایج به سال:
Chipless ultra-wideband (UWB) has been proposed as a low-cost alternative for radiofrequency identification (RFID). In this paper, a comprehensible theoretical introduction to time-domain operation of a UWB RFID tag is described, and a circuit model is proposed. For commercial applications low-cost RFID readers are demanded. To this end, this paper addresses the measurement of time-coded UWB ch...
Ultra-wideband (UWB) technology has gone through some revolutionary changes this year, including the legalization of the technology in the US for imaging systems, vehicular radar systems, and communications and measurement systems. The allocation of 7.5 GHz worth of new, unlicensed spectrum that can be used for communications and measurement techniques, in particular, has sparked a renewed inte...
A novel planar ultra-wideband (UWB) antenna with triple-notched bands using triple-mode stub loaded resonator (SLR) is presented in this paper. The basic UWB antenna consists of a circularshaped radiating element, a 50Ω microstrip feed line, and a partially truncated ground plane. Then, the resonance properties of the SLR are studied. Results reveal that the multiple-mode property of the SLR ca...
In this paper, subject-specific narrowband (2.45 GHz) and ultra-wideband (3–10.6 GHz) on-body radio propagation studies in wireless body area networks (WBANs) were performed by characterizing the path loss for eight different human subjects of different shapes and sizes. The body shapes and sizes of the test subjects used in this study are characterised as thin, medium build, fatty, shorter, av...
Radio communications using ultra wideband (UWB) frequency have rapidly developed since the beginning of the year 2000. This technique offers advantages that made it attractive to a large number of civilian and military applications. The aim of this work is the study of the geometry features of a UWB antenna and the improvement of the bandwidth by inserting slots. To obtain a very large bandwidt...
There exist a lot of methods for vision through an opaque medium. At present UWB (Ultra-Wideband) technology is used more and more because it is suitable for localization and detection of a human body behind a wall. First of all this paper describes known methods for vision through walls, which can be divided into two general groups imaging and non-imaging systems. Secondly it describes the sta...
In this letter, we propose a multi-user detection scheme based on a hidden training sequence for DS-UWB systems. The hidden training sequence, which uses a fraction of the informative sequence’s transmitting power as training information, is utilized for the receiver filter adaptation and channel estimation. By using this, the proposed scheme offers increased bandwidth efficiency (no period ded...
Ultra wideband (UWB) technology based primarily on the impulse radio paradigm has a huge potential for revolutionizing the world of digital communications especially wireless communications. UWB provides the integrated capabilities of data communications, advanced radar and precision tracking, location, imperceptibility and low power operation. It is therefore ideally suited for the development...
In order to estimate performance of Ultra-wideband (UWB) systems and their coexistence with licensed radio services, a characterization of the power spectrum density is required, in particular the influence of the pulse shape used and the pulse repetition rate. In this paper, an improved and faster periodogram algorithm is applied to UWB signals, in order to make use of the special characterist...
The focusing resolution is very important performance for ultra wideband (UWB) imaging system. In this paper, the accuracy of focusing resolution with time-reversal (TR) electromagnetic (EM) pulse propagation is analyzed. The TR EM pulse propagation is done via the numerical simulation of finite difference time domain (FDTD) method. The modulated Gaussian pulse is used as the UWB EM pulse. The ...
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