41 research outputs found
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Mutual coupling suppression in multiple microstrip antennas for wireless applications
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonMutual Coupling (MC) is the exchange of energy between multiple antennas when placed on
the same PCB, it being one of the critical parameters and a significant issue to be considered
when designing MIMO antennas. It appears significantly where multiple antennas are placed
very close to each other, with a high coupling affecting the performance of the array, in terms
radiation patterns, the reflection coefficient, and influencing the input impedance. Moreover;
it degrades the designed efficiency and gain since part of the power that could have been
radiated becomes absorbed by other adjacent antennas’ elements. The coupling mechanism
between multiple antenna elements is identified as being mainly through three different paths
or channels: surface wave propagation, space (direct) radiation and reactive near-field
coupling.
In this thesis, various coupling reduction approaches that are commonly employed in the
literature are categorised based on these mechanisms. Furthermore, a new comparative study
involving four different array types (PIFA, patch, monopole, and slot), is explained in detail.
This thesis primarily focuses on three interconnected research topics for mutual coupling
reduction based on new isolation approaches for different wireless applications (i.e. Narrowband,
Ultra-wide-band and Multi-band).
First, a new Fractal based Electromagnetic Band Gap (FEBG) decoupling structure between
PIFAs is proposed and investigated for a narrowband application. Excellent isolation of more
than 27 dB (Z-X plane) and 40 dB (Z-Y plane) is obtained without much degradation of the
radiation characteristics. It is found that the fractal structures can provide a band-stop effect,
because of their self-similarity features for a particular frequency band.
Second, new UWB-MIMO antennas are presented with high isolation characteristics.
Wideband isolation (≥ 31 dB) is achieved through the entire UWB band (3.1-10.6 GHz) by
etching a novel compact planar decoupling structure inserted between these multiple UWB
antennas.
Finally, new planar MIMO antennas are presented for multi-band (quad bands) applications.
A significant isolation improvement over the reference (≥ 17 dB) is achieved in each band by
etching a hybrid solution.
All the designs reported in this thesis have been fabricated and measured, with the simulated
and measured results agreeing well in most cases
Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)
Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression
Recent Advances in Antenna Design for 5G Heterogeneous Networks
The aim of this book is to highlight up to date exploited technologies and approaches in terms of antenna designs and requirements. In this regard, this book targets a broad range of subjects, including the microstrip antenna and the dipole and printed monopole antenna. The varieties of antenna designs, along with several different approaches to improve their overall performance, have given this book a great value, in which makes this book is deemed as a good reference for practicing engineers and under/postgraduate students working in this field. The key technology trends in antenna design as part of the mobile communication evolution have mainly focused on multiband, wideband, and MIMO antennas, and all have been clearly presented, studied and implemented within this book. The forthcoming 5G systems consider a truly mobile multimedia platform that constitutes a converged networking arena that not only includes legacy heterogeneous mobile networks but advanced radio interfaces and the possibility to operate at mm wave frequencies to capitalize on the large swathes of available bandwidth. This provides the impetus for a new breed of antenna design that, in principle, should be multimode in nature, energy efficient, and, above all, able to operate at the mm wave band, placing new design drivers on the antenna design. Thus, this book proposes to investigate advanced 5G antennas for heterogeneous applications that can operate in the range of 5G spectrums and to meet the essential requirements of 5G systems such as low latency, large bandwidth, and high gains and efficiencies
Effect of electromagnetic fields induced by mobile devices in the human brain
The aim of this thesis is to understand if the devices that produces electromagnetic fields could be a risk for the brain. This work will simulate different scenarios where mobile devices could cause injuries on brain tissues. Numerous articles and works were performed in the past about this subject, however a consensus seems hard to exist. The present master thesis will simulate a variety of scenarios with a brand new realistic simulation computer program named as Sim4life. Sim4Life is a innovative computational life sciences platform that integrate computable human phantoms to analyze biological real-world phenomena
Proceedings of the Fifth International Mobile Satellite Conference 1997
Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments
Reconfigurable Antennas
In this new book, we present a collection of the advanced developments in reconfigurable antennas and metasurfaces. It begins with a review of reconfigurability technologies, and proceeds to the presentation of a series of reconfigurable antennas, UWB MIMO antennas and reconfigurable arrays. Then, reconfigurable metasurfaces are introduced and the latest advances are presented and discussed
Proceedings of the Third International Mobile Satellite Conference (IMSC 1993)
Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial cellular communications services. While the first and second International Mobile Satellite Conferences (IMSC) mostly concentrated on technical advances, this Third IMSC also focuses on the increasing worldwide commercial activities in Mobile Satellite Services. Because of the large service areas provided by such systems, it is important to consider political and regulatory issues in addition to technical and user requirements issues. Topics covered include: the direct broadcast of audio programming from satellites; spacecraft technology; regulatory and policy considerations; advanced system concepts and analysis; propagation; and user requirements and applications
Abstracts on Radio Direction Finding (1899 - 1995)
The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography).
Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM.
The contents of these files are:
1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format];
2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format];
3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion