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Open Journal of Antennas and Propagation, 2013, 1, 1-3 http://dx.doi.org/10.4236/ojapr.2013.11001 Published Online June 2013 (http://www.scirp.org/journal/ojapr) 1 OJAPr Editorial Miroslav Joler Faculty of Engineering, University of Rijeka, Rijeka, Croatia. Email: mjoler@riteh.hr Received May 20th, 2013; Revised June 21st, 2013; Accepted June 27th, 2013 Copyright © 2013 Miroslav Joler. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. On behalf of Scientific Research Publishing (SCIRP) Open Journal of Antennas and Propagation (OJAPr) edi- torial board and staff, it is my honor to write this editorial in the wake of the first issue of the OJAPr. The OJAPr is a new journal in SCIRP’s publishing portfolio, and comes as a natural addition to already present journals pertinent to communications and computer sciences, such as the Int’l Journal of Communications, Network and System Sciences (IJCNS), the E-Health Telecommunica- tion Systems and Networks (ETSN), or the Wireless En- gineerin g a nd T ech nology (WET) journal . Joining the growing trend of open-access journals, that has gained popularity in recent years, the OJAPr has also adopted the policy of open-access publishing, enabling the contributing authors to disseminate their works to a substantially larger public in comparison to member- ship-based journals and at the same time retain the cop y- right on their manuscript, while interested readers have a free access to published papers. In today’s world of fast-paced technological advances in wireless communication devices and services, one component, amongst many other important components, makes it an inevitable part—an antenna. All who know anything about antennas are familiar with their subtle nature: on one hand, a randomly sized and shaped piece of a conducting wire can eventually act as an antenna working at some frequency band and receive or transmit radio waves successfully enough, while, on the other hand, an exact and thorough understanding of antenna parameters and behavior quickly gets complicated and challenging when trying to mathematically describe its characteristics and successfully design it for a specific goal, or computationally analyze it, manufacture it and assemble precisely and finally verify its desired charac- teristics by adequate measurements. Nowadays, we enjoy the commodity of powerful per- sonal computers and advanced computer aided engineer- ing (CAE) software tools to model and predict antenna characteristics by making use of full-wave solvers that are based on some of proven numerical methods, such as the finite-difference time-domain method or the finite element method, and often being empowered by some of popular optimization algorithms, such as the genetic al- gorithm or the particle swarm optimization algorithm, to enable fine tuning of an antenna design in order to meet specific goals, yet in spite of that, it is still not an easy task to design an antenna that will meet specifications of modern communication devices and services, due to an increased number of goals that are to be met. To be able to transfer data using various wireless technologies, for example GSM, WCDMA, UMTS, WLAN, Bluetooth, NFC, WiMAX, or LTE, modern wireless devices (e.g. smartphones, tablets, or laptops) must be equipped with antennas that can efficiently operate at multiple fre- quency bands and that goal requires innovative antenna designs that have not been part of classical antenna text- books and practice. Thus, to meet the required frequency ranges and also fit an antenna into a fairly small space that is left for it in today’s feature-packed devices, pre- sent-day antennas are often designed using some combi- nation slots or slits, electronic switches such as PIN di- odes or MEMS (microelectromechanical switches), vias, and meandering microstrip lines lying on top of the sub- strate, thus producing the so-called frequency-, polariza- tion-, or radiation pattern-agile antennas, which can only be accomplished by an extensive use of CAE tools in order to predict their performance in a sufficiently accurate and time-efficient fashion. On the base station side of an RF link, present chal- lenges are related to implementing techniques for more efficient usage of the available spectrum and a need for an increased channel capacity. As the number of wire- lessly connected gadgets undergoes a strong growth every year, there is a clear need to secure more band- width to accommodate for the growing data amounts. Very soon in the future will the wireless networks have to pass the data amounts that are manifold larger from what we transfer today. Wireless providers are in need for more bandwidth and that will call for a new shift to- wards higher carrier frequencies. There are multiple as- Copyright © 2013 SciRes. OJAPr OJAPr Editorial 2 pects involved in research and development (R&D) ef- forts tackling those issues and the ultimate success is anticipated to be accomplished by no single means, but rather by judiciously combining multiple techniques as discussed next. One aspect of improving the quality of service and in- creasing the capacity lies in implementation of smart(er) antenna arrays on the base station towers. Although the principle of electronic beam scanning has been known for years in radar systems and there has been a good deal of research tackling some sort of smart antennas, it seems that they still have not been adopted in base sta- tions towers to a proportional degree and one reason for that certainly lies in an increased cost that wireless pro- viders would have faced to implement them in their tow- ers due to an increased complexity of such solutions. Smart antennas has been a term denoting antenna arrays that can electronically adjust their radiation pattern to follow select mobile station(s) or/and reduce the level of interference from undesired sources. Depending on the specific goals that were set in the pertinent works, there is a variety of alternativ e terms that are close to the term “smart antennas”. Most commonly they are referred to as the beam-forming arrays, adaptive antennas (or adaptive arrays), up to a more recent terms of self-adaptive arrays and self-recoverable antennas. Additionally, channel capacity can be increased by making use of polarization agility or diversity by having a set of orthogonally polarized antennas, or using elec- tronic switches to switch between the orthogonal polari- zations. While increasing the channel capacity has so far been addressed to the base station side, it can be expected in the future that part of that process will be assigned to mobile handset antennas as well by making them smarter and reconfigurable and that R&D has been underway for some time now, too. Yet another known way to increase the network capac- ity was to reduce the cell size of a wireless network, while at the same time helping mobile handsets work with a lower output power, thus reducing the specific absorption ratio (SAR) that a broad public is getting more sensitive to in the context of possible health effects of radio waves. Since the quantity of data being transferred over wire- less networks is growing fast every year, due to a fast- growing number of wireless devices and users requesting always-on connection to their emails, websites, social networks, for playing or sharing videos on-the-go, cur- rent 4G networks are, or will soon be, about their maxi- mum capacity and will have to be replaced with faster networks containing more bandwidth. Due to that, it is expected that 5G networks will have to be defined and implemented by about 2020. Research efforts in that sense are already underway (see, e.g., Samsung R&D, the METIS project in Europe, or the WiGig alliance). The major directions of that R&D will likely include a further reduction of the cell size, thereby forming the so-called pico cells or femtocells and by moving the car- rier frequency to a millimeter-wave range, yet simulta- neosly retaining the request for having multi-band an- tennas that will have to cover more than eight frequency bands in order to support all wireless standards. It is pos- sible than novel modulation schemes will also be inves- tigated in order to support the ov erall change towards 5G standards. As devices working in the millimeter-wave range will exhibit a shorter rang e to the base station than current mobile handsets, as higher frequencies are prone to higher attenuation, additional base stations will have to be “inserted” into the existing 4G networks. Because of that, it can be expected that additional research will take place searching for more accurate models in describing a communication ch annel under such cond ition, where one small niche of th at will be abou t the wireless netwo rks of future airplanes, that are anticipated to replace a sizeable portion of current wiring with wireless networks, to make the airplanes lighter and offer personal communications and entertainment services available to all passengers wi- thout compromising safety of plane navigation. Another important area of R&D nowadays includes terahertz frequencies. Applications related to them typi- cally involve various noninvasive safety systems like those for airport passenger screening, or detection of ex- plosives, early detection of cracks in the solid materials etc. Terahertz frequencies and applications have gained interest in recent years for their ability to penetrate into materials and trigger their distinct spectral signature that can be used to detect certain substances or warn on pos- sible cracks in the material and more R&D can be an- ticipated in that d irection to take a full advantag e of their promising traits. Taking into account the whole package of having to achieve a further progress in reconfigurable multi-band antennas that will be even smaller than the present-day antennas, due to a shift in operating frequencies towards 60 GHz and higher, along with the anticipated changes in the network infrastructure, and new conditions in the future communication channels, the upcoming years aiming for 2020 (or as close to it as possible) offer plenty of R&D excitement in the wireless technolog y arena and the goal to attain wireless data rates in the order of giga bits per second, which will be 10 to 100 times more than we can afford today. Having all the aforementioned in mind, establishing a journal specializing in antennas and propagation was a logical next step for SCIRP. The OJAPr invites research- ers to submit their original research work for possible publication, whose focus matches the general aims of the journal—discussing ideas and research results pertinent Copyright © 2013 SciRes. OJAPr OJAPr Editorial Copyright © 2013 SciRes. OJAPr 3 to analysis, design, development, optimization, meas- urement techniques, and applications of antennas and propagations models. The scope of the journal falls within a wide range of categories including, but not lim- ited to, Active and Adaptive Antennas, Antennas Analy- sis and Design, Beam Control and Steering, Channel Modeling, Intelligent Antennas, Millimeter-Wave Tech- niques, or Radio Wave Propagation. For a more detailed list of topics please visit the OJAPr website. All submit- ted manuscripts will undergo a rigorous peer-review process being conducted by the OJAPr Editorial Board, which is staffed by experienced international researchers. The OJAPr office is thankful to its first Editorial Board members who readily offered their service to the journal and will be helping the manuscript submission and re- view process, namely: Prof. Ahmed M. Attiya as Edi- tor-in-Chief, and Prof. Federico Alimenti, Dr. Haroldo T. Hattori, Prof. M. Ali Hooshyar, Dr. Miroslav Joler, Dr. Chi-Wah Kok, Prof. Igor V. Minin, Dr. Vaclav Papez, Dr. Càndid Reig, Dr. Zaharias D. Zaharis, and Dr. Domenico Zito, as Editorial Board members, listed in an alphabeti- cal order. Again, on behalf of the Editorial Board members, my- self, and all of the OJAPr staff members who will be serving the publication process, it is my pleasur e to inv ite researchers to prepare and submit to SCIRP’s OJAPr manuscripts describing their original research results for possible publication. Short reports and book reviews are also welcome, subject to OJAPr aims, scope, particular topics, and manu script preparation gu idelines th at will be maintained on the OJAPr web website. Sincerely, Miroslav Joler, Ph.D. OJAPr Editorial Board Member |