Uwb

В данной работе предлагаются три различные модели для описания диаграмм направленности TEM рупора в E-плоскости в сверхширокой полосе частот. Каждая из предлагаемых моделей различаются по точности, частотной полосе и по времени вычисления. Модели сравниваются между собой и с методом конечных элементов. Приведенные данные о полосе согласования по коэффициенту отражения позволяют сделать вывод, что наибольший интерес представляют исследования диаграммы направленности в границах этой полосы, от 1 до 15 ka. Предлагаемые модели вполне описывают изменение диаграммы направленности в E-плоскости во всей полосе согласования антенны и открывают новые возможности для оптимизации нерегулярного СШП TEM рупора по характеристикам диаграммы направленности.

A wide variety of sensors have been used to attempt to most accurately calculate
the positions of UAV drones in swarms. Global Positioning System (GPS), Inertial
Measurement Unit (IMU), and Ultra-Wideband (UWB) are the most common and the
most reliable sensors that are used. This proposed fusion method uses a novel Double
Kalman Filter method to combine the data from these 3 sensors to most accurately
achieve cooperative positioning. In the simulation, we used 30 UAVs as a swarms to
verify the validity of the method. As the results shown, our method outperformed
several other methods.

This research presents the development of a self-governing mobile robot navigation system for indoor construction applications. This self-governing robot navigation system integrated robot control units, various positioning techniques including a dead-reckoning system, a UWB platform and motion sensors, with a BIM path planner solution. Various algorithms and error correction methods have been tested for all the employed sensors and other components to improve the positioning and navigation capability of the system. The research demonstrated that the path planner utilizing a BIM model as a navigation site map could effectively extract an efficient path for the robot, and could be executed in a real-time application for construction environments. Several navigation strategies with a mobile robot were tested with various combinations of localization sensors including wheel encoders, sonar/infrared/thermal proximity sensors, motion sensors, a digital compass, and UWB. The system successfully demonstrated the ability to plan an efficient path for robot's movement and properly navigate through the planned path to reach the specified destination in a complex indoor construction site. The findings can be adopted to several potential construction or manufacturing applications such as robotic material delivery, inspection, and onsite security.

This thesis evaluates the potential of Ultra Wideband Impulse Radio for wireless sensor network applications.

Wireless sensor networks are collections of small electronic devices composed of one or more sensors to acquire information on their environment, an energy source (typically a battery), a microcontroller to control the measurements, process the information and communicate with its peers, and a radio transceiver to enable these communications. They are used to regularly collect information within their deployment area, often for very long periods of time (up to several years). The large number of devices often considered, as well as the long deployment durations, makes any manual intervention complex and costly. Therefore, these networks must self-configure, and automatically adapt to changes in their electromagnetic environment (channel variations, interferers) and network topology modifications: some nodes may run out of energy, or suffer from a hardware failure.

Ultra Wideband Impulse Radio is a novel wireless technology that, thanks to its extremely large bandwidth, is more robust to frequency dependent propagation effects. Its impulsional nature makes it robust to multipath fading, as the short duration of the pulses leads most multipath components to arrive isolated. This technology should also enable high precision ranging through time of flight measurements, and operate at ultra low power levels.

The main challenge is to design a system that reaches the same or higher degree of energy savings as existing narrowband systems considering all the protocol layers.

As these radios are not yet widely available, the first part of this thesis presents Maximum Pulse Amplitude Estimation, a novel approach to symbol-level modeling of UWB-IR systems that enabled us to implement the first network simulator of devices compatible with the UWB physical layer of the IEEE 802.15.4A standard for wireless sensor networks.

In the second part of this thesis, WideMac, a novel ultra low power MAC protocol specifically designed for UWB-IR devices is presented. It uses asynchronous duty cycling of the radio transceiver to minimize the power consumption, combined with periodic beacon emissions so that devices can learn each other's wake-up patterns and exchange packets. After an analytical study of the protocol, the network simulation tool presented in the first part of the thesis is used to evaluate the performance of WideMac in a medical body area network application. It is compared to two narrowband and an FM-UWB solutions. The protocol stack parameters are optimized for each solution, and it is observed that WideMac combined to UWB-IR is a credible technology for such applications. Similar simulations, considering this time a static multi-hop network are performed. It is found that WideMac and UWB-IR perform as well as a mature and highly optimized narrowband solution (based on the WiseMAC ULP MAC protocol), despite the lack of clear channel assessment functionality on the UWB radio.

The last part of this thesis studies analytically a dual mode MAC protocol named WideMac-High Availability. It combines the Ultra Low PowerWideMac with the higher performance Aloha protocol, so that ultra low power consumption and hence long deployment times can be combined with high performance low latency communications when required by the application. The potential of this scheme is quantified, and it is proposed to adapt it to narrowband radio transceivers by combining WiseMAC and CSMA under the name WiseMAC-HA.

In this paper, on-body propagation modelling has been investigated applying various numerical computational techniques. Propagation measurements with body-worn antennas have been carried out at 2.4 GHz inside and outside an anechoic chamber respectively for narrowband communication channel characterisation. Both simulation and measurement results have been also obtained at the UWB (ultra wide-band) band.

—The presented paper exhibits a coplanar waveguide (CPW)-fed symmetrical staircase shaped, planar monopole Ultra Wideband (UWB) antenna having dimensions 40x30x1.6mm 3 with 5GHz WLAN notch band characteristic. The staircase pattern in the radiating patch and the U-shaped slot resonator in the feed line are used to achieve the UWB and notch the 5GHz WLAN band, respectively. The proposed antenna has impedance bandwidth ranging from 2.84GHz-13.9GHz to cover UWB. Interference caused by WLAN band from 5.15GHz-5.35GHz and 5.725GHz-5.825GHz is notched effectively. The proposed antenna has been printed on FR4 substrate with dielectric constant of 4.4 and thickness of 1.6mm. Moreover, the fabricated prototype antenna shows a good agreement between the simulated and measured results. Keywords— CPW, monopole, staircase rectangular patch, notched band, ultra wide band (UWB)

Low noise amplifier is a crucial and essential component in RF receiver design. It amplifies the received weak RF signal with minimum noise contribution. Designing Low noise amplifier with CMOS technology is one of the important topics in research fields due to its advantages of low power, low cost and higher integration. Applications of LNA include WLAN, WSN and UWB applications. In this paper a detailed survey is provided for various LNA design techniques. The designed circuit is simulated using Advanced Design System (ADS) software.

In this article, a dual-band WLAN/ultrawideband (UWB) printed wide slot microstrip-fed antenna is presented for multi-input multi-output (MIMO)/diversity applications. The proposed antenna consists of a U-shaped patch, a T-shaped monopole path, and a pentagonal wide slot in the ground plane. The antenna is designed to cover both the WLAN (2.4-2.485 GHz) and UWB (3.1-10.6 GHz) ranges, with value of S 11 below À10 dB. The antenna is constructed on a FR4 substrate with overall dimensions of 28 Â 28 Â 1 mm 3. It is shown that the proposed dual-band antenna is suitable for diversity polarization applications. The simulation results show that the different configurations of the antenna in the MIMO/diversity have good S-parameters over the operating frequency bands. The simulation and measured results of the proposed dual-band antenna as well as that of the MIMO/diversity antenna configuration agree well. V C 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:461-465, 2013; View this article online at wileyonlinelibrary.com.

A compact slotted Ultra Wide Band (UWB) antenna suitable for wireless Universal Serial Bus (USB) dongle application is designed and simulated using Ansoft HFSS14.0. Antenna design for USB dongle will be a challenging task due to its space constraint and it also needs to maintain good impedance and radiation performance across a wide operating bandwidth. Here this UWB antenna is designed by simply cutting notches and embedding slots in the patch in order to achieve multiple resonance having effective bandwidth of about 10.42 GHz (2.8 to 13.38GHz) with 3dBi of peak gain which covers operating band of WPAN using UWB. Gain is further enhanced by using electromagnetic band-gap (EBG) structure concepts. Overall size of UWB antenna is 11x15x0.8mm3 which is very suitable for USB Dongle device.

In this paper a dual port microstrip antenna with tunable band pass filter is proposed for cognitive radio applications. In single port reconfigurable antennas for cognitive radio, sensing and communication is done simultaneously. This can lead to failure of real time communication, also it may induce interference to primary user, dual antenna system solves this problem. The proposed antenna consist of one UWB microstrip antenna for sensing the holes in spectrum and other is communication antenna. Communication antenna is made tunable by using varacter diode in 'G' shaped DMS(defected microstrip structure) filter integrated in feedline.The sensing antenna is having UWB bandwidth from 3.4 GHz to 13.2 GHz and efficiency of more than 80%. The narrowband antenna has dual and triple operating frequencies which is tunable in the range of 4-5 GHz, 6-10 GHz and 10-11 GHz according to the biasing of varacterdiode. This antenna as efficiency more than 70%. .

The problem of synthesis and analysis of circular antenna array for the
azimuth scanning in ultra-wide band (more than 1:100) is considered. The review of
UWB radiators used as the elements of antenna arrays is given. The results of the
matching characteristics analysis of various modifications of TEM horns have been
obtained with the use of a numerical-analytical theory and FEM are given. Numerical
modeling of the matching characteristics of and radiation of a circular antenna array
of asymmetrical loop TEM horns as elements is done. Comparison of the results of
numerical simulation and physical experiment is conducted.

A compact multiband‐notched printed ultra‐wideband (UWB) coplanar waveguide (CPW)‐fed slot antenna is presented. The band notched characteristic is achieved by creating quarter‐wavelength stubs in the ground plane. These stubs act as stop‐band filters along the feed line over certain narrow frequency bands. Addition of each stub to the antenna structure creates an extra independent notch band. Antenna with single, dual, triple, quadruple, and penta notch bands can be created by this technique. The notch bands can be chosen from practical frequency bands such as 3.5 GHz WiMAX, 5.2 and 5.8 GHz WLAN, 7.25–7.75 GHz for the downlink of X‐band satellite communication systems, and ITU at 8.2 GHz band all within the UWB range. Each of the notch bands can be tuned in frequency independently. The antenna has a small size (24 × 27 × 0.8 mm3), and almost stable omnidirectional radiation pattern. The prototype of the antenna is fabricated, and the measured results are in good agreement with the simulations.

There is a growing interest for simultaneous identification and centimetre-resolution localization of multiple targets in indoor environments. A hybrid passive UHF/UWB RFID concept has been recently proposed that conciliates the potential from high resolution UWB impulse radio with the typical range from UHFRFID identification systems. This paper proposes a new planar antenna for hybrid passive tag systems, which operates both in the UHF-RFID band and in the FCC UWB band. The co-designed UHF andUWB antenna elements are printed back-to-back on each side of a common substrate with appropriate topology for future integrationwith a single UHF-UWBRFIDchip. Experimental tests have shown that both UHF-RFID and UWB performance of the hybrid antenna are comparable to available commercial solutions that work just on a single band. The antenna is adequate for lowcost mass production of hybrid passive tags. It aims at low-cost passive RFID systems combining the ability of item identification with precise tracking in indoor environments.

Four iterations of a Coplanar Waveguide (CPW)-Fed KOCH SNOWFLAKE fractal antenna are studied. Increasing the number of iterations allow us obtaining a simple and miniaturized antenna with good performances, operating for Ultra Wide Band (UWB) applications. The proposed antennas are a good solution for the 3.7-4.2GHZ C-Band, the 5.15-5.82 Wireless Local Area Network (WLAN), and for the 5GHZ Worldwide Interoperability for Microwave Access system (WIMAX) applications. The simulation was performed in FEKO 6.3.

Matching and radiation characteristics of a horn-lens TEM antenna are studied theoretically and experimentally in an ultra-wide frequency band. Theoretical results are obtained by means of electromagnetic modeling on the basis of the finite-element method. Antennas with different geometries of the lens and different methods of excitation of the TEM horn are considered. Direct excitation by a coaxial line and excitation with the use of a smooth transition from a coaxial line to a stripline are studied. The results of calculations are compared with experimental results.

Using an asymptotic solution to the 2D diffraction problem for the open end of a horn, the method transverse sections, and the results of the numerical analysis, a numerical-analytical model for matching of symmetric TEM horns is built. The finite element method is used to estimate the accuracy of this model. The model is used to find optimum values of the input and output characteristic impedances as well as the variation law of this impedance along the horn length optimal from the viewpoint of obtaining the minimum value of the low-frequency boundary of matching at a level of −10 dB for a semiinfinite frequency band. The finite element method is used to refine the values of the determined parameters. Matching characteristics of synthesized horns are compared with available results.