Analysis of the EM scattering from arbitrary open-ended waveguide cavities using axial Gaussian Beam tracking

The electromagnetic (EM) scattering from a planar termination located inside relatively arbitrarily shaped open-ended waveguide cavities with smoothly curved interior walls is analyzed using a Gaussian Beam (GB) expansion of the incident plane wave fields in the open end. The cavities under consideration may contain perfectly-conducting interior walls with or without a thin layer of material coating, or the walls may be characterized by an impedance boundary condition. In the present approach, the GB's are tracked only to the termination of the waveguide cavity via beam reflections from interior waveguide cavity walls. The Gaussian beams are tracked approximately only along their beam axes; this approximation which remains valid for relatively well focussed beams assumes that an incident GB gives rise to a reflected GB with parameters related to the incident beam and the radius of curvature of the wall. It is found that this approximation breaks down for GB's which come close to grazing a convex surface and when the width of the incident beam is comparable to the radius of curvature of the surface. The expansion of the fields at the open end depend on the incidence angle only through the expansion coefficients, so the GB's need to be tracked through the waveguide cavity only once for a wide range of incidence angles. At the termination, the sum of all the GB's are integrated using a result developed from a generalized reciprocity principle, to give the fields scattered from the interior of the cavity. The rim edge at the open end of the cavity is assumed to be sharp and the external scattering from the rim is added separately using Geometrical Theory of Diffraction. The results based on the present approach are compared with solutions based on the hybrid asymptotic modal method. The agreement is found to be very good for cavities made up of planar surfaces, and also for cavities with curved surfaces which are not too long with respect to their width

Letter from the editors: Volume 10, Issue 2

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From the Editor

From the Edito

Editorial

In 2016, Higher Learning Research Communication (HLRC) celebrates its 6-year anniversary. The journal is a collaborative effort amongst Universidad Andrés Bello (Chile), Universidad Europea de Madrid (Spain), Istanbul Bilgi University (Turkey), and Walden University (United States). These four institutions started this journal to provide scholarly focus on international research in higher education, teaching and learning, education policy and practice, and internationalization. It was important that the journal be open access, so that everyone could have immediate and unrestricted access to the latest research. It was also important that the journal be multilingual; we have accepted manuscripts for review in Brazilian Portuguese, European Portuguese, Latin American Spanish, European Spanish, and English. The language capacity of the staff is truly amazing. As I begin my first year as Chief Editor, I have had the time to reflect on the many accomplishments of HLRC. HLRC has published 88 essays, articles, lections, book reviews, and editorials. Several special issues have been published, including Accreditation (2012); Tourism, Hospitality and Leisure in a Globalized World (2012); Selected Papers from the International Conference on Teaching and Learning (2013); International Perspectives on Retention (2014); and English Medium Instruction (EMI) and Content and Language Integrated Learning (CLIL) (2015). We have been fortunate to have essays by scholars such as Drummond Bone, Internationalization (2011); Bill Plater, Quality Assurance (2013); Rogerio Meneghini, Scielo and Open Access Journals (2013); Watson Swail, A Different Viewpoint on Student Retention (2014); and Gonzalo Fernandez-Sanchez, María Olga Bernaldo, Ana Castillejo, and Ana María Manzanero, Education for Sustainable Development in Higher Education: State-of-the-art, Barriers, and Challenges (2014). I greatly appreciate the breadth of scholarship on the latest higher education practices and authors who are writing on issues that are important and relevant to the higher education landscape. We have also seen some great improvements in our metrics. For example, due to some changes to our website in 2015, we saw a significant increase in visits to the HLRC site and more citations. We have averaged about a 53% acceptance rate, which reflects our adherence to quality standards for publication. We also added more content to the website, including information on copyright, self-archiving policies, conflicts of interest, and publication ethics. The new section on author guidelines provides much clearer information that will help with manuscript preparation and submission. In addition, we are registered with a number of indexation services, such as Google Scholar, and our articles are included in ProQuest Education Journals, Questia, and OJS/PKP Library network. We submitted an application for indexation of HLRC, and we should hear back on this initiative sometime later in 2016. I look forward to an exciting 2016. We have two special issues planned. The June 2016 special issue on Higher Education, Community Engagement, and the Global Public Good will commemorate the 5-year anniversary of HLRC. In December, there will be a special issue dedicated to Quality Assurance in Higher Education. We continue to also seek the best research that you are doing for publication, as well as book reviews and other kinds of scholarly contributions. I have been working with the editorial staff to reorganize the editorial board to include associate editors; we are also going to be seeking a broad set of peer reviewers from countries around the world upon whom we can call to review manuscripts. It is my goal to help broaden visibility and readership of HLRC and to make it one of the journals of choice for submissions regarding higher education. I invite you to visit the site at www.hlrcjournal.com and browse the titles of previously published manuscripts. If you are interested in joining the editorial board as an associate editor, or if you would like to serve as a peer reviewer, please do not hesitate to contact me. We welcome new doctoral scholars as well as those who are advanced in their doctoral programs who would like to engage in this type of professional development opportunity

Letter From the Editor

Letter from the Edito

Editorial

We are pleased to publish five essays as part of our co-sponsorship of the MAGIC (Methods, Aesthetics, & Genres in Communication) conference organized by the University of Petroleum and Energy Studies (UPES) in Dehradun, Uttarakhand, India. This conference was organized by Center for Professional Communication under the aegis of the College of Engineering Studies. The purpose of the conference was to bring together academicians and researchers to deliberate and discuss upon developing communication skills. The emphasis was on empowering the workforce with effective and sustainable communication skills. The conference also supports the efforts of Skill India to help enhance the skills of its populations