نتایج جستجو برای: wideband uwb
تعداد نتایج: 13346 فیلتر نتایج به سال:
Ultra-wideband (UWB) communications systems provide extremely high data rates while using low transmit power relative to narrowband systems. Recent research concludes that such systems have characteristics that make them appropriate for highspeed wireless network applications. One of the distinguishing aspects of the UWB signal is an extremely high fractional bandwidth when compared with conven...
a fully integrated, ultra low-power, varying pulse width fifth-order derivative Gaussian pulse generator designed and fabricated in a commercial 0.18μm CMOS technology is reported for 3-10GHz impulse ultra wideband (UWB) transceivers. The fifth-order derivative Gaussian pulse generator circuit consists of four parallel Gaussian pulse formation blocks and an output stage. It can generate UWB pul...
This paper includes a new technique for media access control (MAC) in the Ultra Wide Band (UWB) spectrum. We use a TDMA based protocol that utilizes Multiband Impulse-based Ultra Wideband (MI-UWB). The proposed MAC protocol (UWB-MAC) uses TDMA on multiple bands to maximize throughput for streaming media applications. This is accomplished by using MI-UWB in combination with TDMA on multiple chan...
For an indoor ultra-wideband (UWB) communication system, the line-of-sight (LOS) between the transmitter and receiver may be frequently blocked by moving people. Blocking of LOS may significantly affect the quality of service of on-going UWB communications. Based on the Angular Power Spectrum Density and the human blocking models, we build a packet-level UWB channel model considering the shadow...
This study describes the bending effect on an Ultra Wideband (UWB) microstrip patch antenna on the antenna performance in terms of impedance bandwidth and radiation pattern. Comparison is done between the UWB planar antenna and the bent UWB antenna. The bending effect causes shift in resonant frequencies with slight change in the impedance bandwidth. A circuit model comprising lumped elements i...
This paper presents the results of a co-existence study investigating the impact of ultra wideband (UWB) interference on an IEEE802.11b network. Results are based on the experimental test measurements made at the University of Oulu, Finland using simple non-FCC compatible, high power UWB transmitters as interference sources. Preliminary results showed that the IEEE802.11b network suffered sligh...
In this paper a particle swarm optimization (PSO) algorithm is presented to design a compact stepped triangle shape antenna in order to obtain the proper UWB bandwidth as defined by FCC. By changing the various cavity dimensions of the antenna, data to develop PSO program in MATLAB is achieved. The results obtained from the PSO algorithm are applied to the antenna design to fine-tune the bandwi...
An ultra-wideband (UWB) self-complementary planar bow-tie antenna (SCPBTA) is proposed. The antenna consists of a printed conical horn-shaped (CHS) radiator and a counterpart CHS slot etched on a rectangular ground plane. The printed CHS radiator is connected directly to the 50Ω microstrip line by bending the end portion of the feed line. As a result, the antenna has a simple structure which do...
For many applications, wideband signals are exploited for localization. A wideband signal is any signal whose energy is distributed over a bandwidth that is large in comparison to the signal’s center frequency. For example, ultrawideband (UWB) noise radars use wideband offering low probability of detection (LPD), while achieving good target detection and high resolution [1]. In the acoustic veh...
A concept for wideband electronic steered array using analogue FIR-filters has been formulated. This paper focuses on microwave applications, e.g. wideband antenna radiation pattern, where we explain the design of a desired radiation pattern for bandwidth 2:1. Therefore we consider a linear narrowband radiation pattern and expand it to a wideband array synthesis. The requirements for higher ban...
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