نتایج جستجو برای: ultra wideband uwb
تعداد نتایج: 66975 فیلتر نتایج به سال:
This paper evaluates the level of interference caused by different ultra-wideband (UWB) signals to other various radio systems, as well as the performance degradation of UWB systems in the presence of narrowband interference and pulsed jamming. The in-band interference caused by a selection of UWB signals is calculated at GSM900, UMTS/wideband code-division multiple-access (WCDMA), and global p...
Printed-circuit board (PCB) elliptic antennas with useful bandwidth exceeding 10:1 ratio are suitable for wideband radar, wireless ultra wideband (UWB) and other wireless communication applications. We present wideband PCB elliptic dipole antennas which are capable of achieving the bandwidth requirements for all the applications. A set of elliptic dipole antennas with varying eccentricities hav...
The next generation RFID system for ubiquitous identification and sensing requires both energy and system efficiency. This paper describes an efficient passive RFID system using impulse ultra-wideband radio (IR-UWB), at a 10m operation range. Unlike conventional passive RFID systems which rely on backscatter and narrowband radio, IR-UWB is introduced as the uplink (communication from a tag to a...
In this report, we derive the performance graphs for UWB communication systems using different combining techniques in a RAKE Receiver. Comparisons have also been made between the techniques and conclusions have been drawn based on the requirements. We also incorporate the effect of number of fingers on the performance of the receivers. The results obtained give us way to evaluate the performan...
UWB radar system facilitates us to estimate positions and shapes of the objects behind the wall. It has a great utilization especially for rescue and security applications. This paper briefly describes all signal processing steps that are required for Imaging of the objects scanned by ultra wideband radar device. It involves the description of the basic scanning method, data preprocessing and c...
The scaling factor in a ultra-wideband antenna is investigated. Here is showed that the lower frequency limit of the bandwidth is reduced as the scaling factor is bigger than unity. Using the obtained results a UWB planar monopole antenna was designed. The measured antenna bandwidth goes from 650 MHz to 20 GHz for a VSWR ≤ 2. The radiation pattern remains almost omnidirectional. The radiator us...
Ultra Wideband (UWB), an impulse carrier waveform, was applied at HF-VHF frequencies to utilize surface wave propagation. Due to the low duty cycle of the pulse, the energy requirements are significantly reduced. UWB involves the propagation of transient pulses rather than continuous waves which makes the system easier to implement, inexpensive and small. The use of surface wave propagation (in...
The paper presents the basics for implementation of devices using UWB (Ultra-Wideband) technology describing its performances and potential problems as these devices operate over large part of the frequency spectrum that is shared with many radio-communication services. Two elements are considered in particular; the regulatory framework and the question of compatibility or impact that UWB techn...
Airborne ultra wideband (UWB) impulse-radiating antennas (IRAs) present an especially large radar cross section to X–band radar. To mitigate this problem, we have numerically and experimentally investigated the use of a frequency selective surface (FSS) as a broadband filter to reflect X–band radar while transmitting lower-frequency UWB signals without loss or dispersion. We present here result...
Because of the importance of ultra-wideband (UWB) radar in various applications, short pulse generation in UWB systems has attracted a lot of attention in recent years. In order to shorten the pulse, nonlinear transmission line (NLTL) is imported, which expands the application of step recovery diode (SRD) for pulse generation. Detailed analysis and equations for this SRD and NLTL-based pulse ge...
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