Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 31 for “"Directional Antennas"”.
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Miniaturized, Directional Antennas For Wireless Power Transfer
… wireless power transfer. Next, two miniaturized antennas, an electrically small, circular polarized parasitic array antenna, and a miniaturized circularly polarized 2x2 array antenna, are introduced for possible use as wireless power reception antennas. Each antenna utilizes top-loading and …
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Topologies for ad-hoc networks utilizing directional antennas with restricted fields of view
… airborne network in which aircraft have multiple directional antennas that are restricted in their pointing direction. A pair of aircraft in ORCLE can be linked if they both have an antenna pointing at each other. Four topology algorithms, which coordinate the pointing of the antennas and attempt …
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Link Establishment in Ad Hoc Networks Using Smart Antennas
… networks have been designed for nodes using omni directional antennas. Through the use of directional antennas, it is possible to obtain higher efficiency. In this thesis we investigate the impact of these antennas on aggregate throughput and end-to-end delay. The use of omni-directional antennas …
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Analysis of CDMA cellular radio systems employing adaptive antennas
… communication systems employing adaptive antennas at the base station. First, a simple analysis is presented which shows that significant improvements in performance can be obtained by using directional antennas in the mobile-to-base station link of CDMA cellular radio systems. Next, steps …
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Adding direction to a directionless world
… context referred to as orientation. Based on directional antennas and previous work in RSSI based radio distance estimation, this work shows that using directional antennas alone, the angle between two devices can be approximated. Furthermore, this thesis shows the effect of distance …
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Routing in heterogeneous wireless ad hoc networks
… with heterogeneous networks consisting of omnidirectional and directional antennas. A new MAC protocol for directional antennas, request-to-pause-directional-MAC (RTP-DMAC) protocol is developed that solves the deafness issue, which is common in networks with directional antennas. Three new …
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A statistical ultra wideband indoor channel model and the effects of antenna directivity on multipath delay spread and path loss in ultra wideband indoor channels
… were analyzed extensively for various omni-directional and directional antenna combinations. A statistical model of the path loss in the channel is presented, where the parameters in the model (i.e., path loss exponent and shadow fading statistics) are dependent on the particular Tx/Rx …
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Enhancing the energy efficiency of ultra wideband (UWB) based media access control (MAC) protocols in mobile ad-hoc networks (MANETs) through the use of steerable directional antenna
… in Mobile Ad Hoc Networks (MANETs). The use of directional antennas can conserve energy due to the increased gain and directed transmission towards specific point in space. Directional antennas also resolve many issues associated with interference from different points within the network. …
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Capacity and coverage of mmWave ad hoc networks
… higher bandwidth, reduced interference due to directional antennas, and a lighter interference field due to blockage. This report uses a stochastic geometry approach to characterize the one-way and two-way coverage probability of a mmWave ad hoc network with directional antennas and random …
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Directional Communications to Improve Multicast Lifetime in Ad Hoc Networks
… Previous work has investigated the use of directional antennas as a method to reduce inter-node power requirements. However, most proposed methods ignore inter-session interference, propose heuristic solution methods, and ignore the use of directional antennas for signal reception. We …
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Indoor wide band radio wave propagation measurements and models at 1.3 ghz and 4.0 ghz
… obstructed environments offer less than 3 dB. Directional antennas provide a significant reduction in rms delay spread over omni-directional antennas. In line-of-sight environments, circular polarization provides an additional delay spread reduction.
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Antenna effects on indoor wireless channels and a deterministic wide-band propagation model for in-building personal communication systems
… Our results show that vertically polarized (VP) directional antennas at both the transmitter and the receiver can give better delay spread and path loss results than other antenna combinations. The performance of VP directional antennas are found to be sensitive to the alignment of the antennas, …
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Design and measurement of antennas within lossy materials for IoT applications
… materials which cause issues for the embedded antennas. This thesis studies methods of enhancing antenna radiation efficiency in such situations along with an improved, low-cost way of measuring radiation efficiency. Multiple modified Wheeler caps are compared to a conventional design to obtain …
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Wireless Intrusion Detection Sytem
… intelligent access points equipped with rotating directional antennas.
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An investigation into the use of software-defined networking controllers
… algorithm solves the problem of deciding which directional antennas to align to form connections and efficiently processes frequent updates while generating an exact solution for the optimal path.
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Adaptive Antenna Arrays for Satellite Personal Communication Systems
… technique is believed to be better than omni-directional antennas which radiate in all directions. Adaptive antenna arrays have the ability to adapt to the changing environment and null out the interference. The LMS algorithm was investigated and used in the simulation of the adaptive array. …
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Cross-Layer Optimization: System Design and Simulation Methodologies
… MANET wherein the nodes are equipped with smart antennas. Traditional MAC protocols assume the use of omnidirectional antennas. Nodes with directional antennas are capable of transmitting in certain directions only and significantly reduce the chances of collision and increase the effective …
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Millimeter wave communications : from point-to-point links to agile network connections
… high attenuation, and hence have to use highly directional antennas to focus their power on the receiver. Existing radios have to scan the space to find the best alignment between the transmitter's and receiver's beams, a process that takes up to a few seconds. This delay is problematic in a …
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Enabling high-quality untethered virtual reality
… of the headset. Second, mmWave radios use highly directional antennas with very narrow beams; they work only when the transmitter's beam is aligned with the receiver's beam. Any small movement of the headset can break the alignment and stall the data stream. We present MoVR, a novel system that …
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