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4006 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 50, NO. 10, OCTOBER 2012 Electromagnetic Radiation Fields in Three-Layered Media With Rough Interfaces Samira Tadros Bishay, Osama M. Abo-Seida, and Hanan Shehata Shoeib Abstract—Research related to the radiation and propagation of the electromagnetic fields in half space or stratified media is of interest and is considered by many authors. In this paper, a theoretical study is discussed about the propagation of radio waves in the sea (three-layered media). The variations which occur in the shape of the sea surface and sea bottom are considered. The effects of the roughness exercised onto the electromagnetic field of ar- rangements radiating a pure transverse electric field in the sea are studied by using the perturbation method. Closed-form expression for the far field generated by a vertical magnetic dipole embedded below the sea surface is calculated by using a simple technique to evaluate Sommerfeld integrals with the aid of the complex image theory, which was quite difficult to evaluate previously. The results obtained are compared with those mentioned elsewhere. Index Terms—Far field, radiation in the sea, rough surfaces, stratified media, vertical magnetic dipole. I. I NTRODUCTION C OMMUNICATION of radio waves in the sea is required for human activities that take place, particularly in recent years. It is worthwhile researching the far-region electromag- netic radiation due to a vertical magnetic dipole in the sea because it is often used for the underwater communication. Wait [1], Moore and Blair [2], and Durrani [3], considered the problem, but in their works, the sea was assumed to be a two- layered conducting medium (air and seawater). If the sea is proportionally deep to dissipate radio waves, it is reasonable to assume that it is also semi-infinite downward and the sea bottom need not be included. However, the effect of the sea bottom is important in some situations such as a shallow sea, a low frequency, and the transmitting and receiving points are close to the bottom. Thus, Arutaki and Chiba [4] considered the sea as a three-layered conducting medium (air, seawater, and ground) for communication near the sea bottom. They investigated the sequences of considering the sea to be of a finite depth. The effect of the sea bottom was found to play an essential role in the cases mentioned above. In their treatment, however, the sea Manuscript received April 18, 2011; revised October 24, 2011 and January 16, 2012; accepted January 22, 2012. Date of publication April 3, 2012; date of current version September 21, 2012. S. T. Bishay is with the Department of Mathematics, Faculty of Science, Ain Shams University, Cairo 11566, Egypt (e-mail: [email protected]). O. M. Abo-Seida is with the Department of Mathematics, Faculty of Sci- ence, Kafr El-Sheikh University, Kafr El-Sheik 33516, Egypt. Currently with the Department of Mathematics, Faculty of Science, King Faisal University, Al-Ahsaa 31982, Saudi Arabia (e-mail: [email protected]). H. S. Shoeib is with the Faculty of Science, Ain Shams University, Cairo 11566, Egypt (e-mail: [email protected]). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TGRS.2012.2188409 surface was taken to be planar. Afterward, Bishay presented different studies, regarding the effect of the sea waves that occur, on the sea surface only (see [5] and [6]) while others on both the sea surface and the sea bottom (see [7] and [8]). The deviation of the two rough sea surface and sea bottom from flat ones is small and has small slopes. Osama et al. [9] analyzed the effect of sea waves that occur on the sea surface and obtained the formal solution of the far field in the seawater. Recently, Franceschetti et al. [10] investigated analytically the scattering from layered structures with one rough interface. Furthermore, Imperatore et al. [11] studied scattering from layered structures with an arbitrary number of rough interfaces. In this paper, as an alternative, with the aid of the perturbation method which Becker [12] and Bishay and Mohammed [13] used, we study the effect of the variations which occur in both the sea surface and bottom due to the sea waves. Moreover, we look into the solution for the case of uniform sea height (flat one), which Arutaki and Chiba [4] and Long et al. [14] derived. The studies [4]–[8] got the formula of the far field in the seawater by resolving the Sommerfeld integrals through the residue and saddle-point methods. These methods involved lengthy algebra and several transformations which were rather complicated and difficult to evaluate. Studies [4]–[7], also did not calculate or include the disturbed field in the sea or their numerical results. Therefore, in this work, we use a simple technique [14] to evaluate Sommerfeld integrals in a few easily remembered steps with the aid of the complex image theory [15], to obtain a closed-form expression for the far field in the region of the seawater due to a vertical magnetic dipole in a sea. We also offer some numerical calculations which show the importance of the bottom existence and discuss the physical meaning. II. STRUCTURE OF THE SPACE UNDER I NVESTIGATION We adopt the following model as shown in Fig. 1. A small electric current loop antenna, whose magnetic moment is IS 0 , is located in the middle layer (i.e., in the sea) at depth d 1 , horizontally. An observing point p(r, z) is located at depth d 2 . We suppose that the thickness of the sea is a, and that air is infinite upward and the ground downward along the z-axis. All regions are infinite sideward and are homogeneous. R is the distance between the source and the observation point P . The material constants are assumed to be as follows. The dielectric constant in the air, sea, and ground are ε 0 , ε 2 , and ε 3 , respectively. The magnetic permeability is taken equal to that of the free space in every layer. The conductivity of the 0196-2892/$31.00 © 2012 IEEE

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6 Bosque Azul Work: 505-667-2340 [email protected] Santa Fe, NM 87507 Mobile: 339-225-0536 [email protected]

!Competencies Document

•! Real world experience and innovative thinking o! Comfort with risk: 2 library start-ups and business owner. o! More than twenty-four years experience in academic, corporate, and government settings. o! Personal philosophy and practices influenced by TRIZ thinking; Robert D. Putnam’s Better

Together initiatives; charrette processes; scenario planning; and servant leadership. •! Leadership and vision

o! Lead and manage 30-person organization with $10 million budget serving 10,000 scientists, engineers, students and staff. Successfully transitioned to Los Alamos National Laboratory (LANL) from Olin College where I lead and managed a 3-person organization and an approximate $2 million budget serving 35 faculty members and 350 students.

o! Convene Library Advisory Board made up of researchers, scientists and engineers from across the Lab.

o! 2017 President, Special Libraries Association (SLA), an international organization with members in over 75 countries.

o! Created 2017 – 2019 Strategic Plan for Los Alamos Research Library, using community process that engaged stakeholders and staff. Roadmap development is now in process. Also created vision and strategic plan for Olin College library.

o! Achieve success in goals across broad range of work environments, from open & innovative (Olin, Wieden + Kennedy) to highly structured (LANL).

•! Collaboration and partnerships o! Collaborate with CIO’s office at LANL through membership on classified review board as well as

testing potential digital Lab tools within Research Library. o! Partner with Los Alamos Tech Transfer center to connect content elements of research throughout

lifecycle, from ideas in lab books through publications and patents. o! Designed, planned and implemented an Ebook Summit at Olin College, bringing together

computer programmers, designers, publishers, faculty, students and librarians to discuss technical, tenure, design and access issues surrounding electronic books in academia.

o! Visited and benchmarked existing academic consortia to inform creation and strengthening of Babson-Olin-Wellesley consortium. Consortia included Claremont Colleges, Five Colleges (western MA), Tri-College (Bryn Mawr, Haverford, Swarthmore) and Colby-Bates-Bowdoin.

•! Digital library innovation o! Building internal partnerships and workflows to communicate LANL research to a public audience

through creation of abstracts written in layperson language then addition of abstracts to the institutional repository.

o! Drove creation of first publicly accessible Department of Energy research lab institutional repository at LANL.

o! Researched strategy for institutional repository at Olin College, balancing staff capabilities against budget. Chose product and implemented with vendor, faculty and staff.

o! Researched and implemented solutions to faculty research and metrics challenges at Olin College. Provided full access to library databases from any location at any time.

o! Evaluated a range of discovery and federated search products at Olin College. Oversaw implementation of product with vendor, library & IT staff.

•! Commitment to diversity and development o! Created Diversity and Inclusion Task Force for SLA to take on 2017 study of role and place of

diversity in association and profession. What are the current needs? What role can the association play? Where can we have an impact? Created and led Inclusion Caucus within SLA focused on speakers at conferences, resource materials and mentoring.

o! Strong international perspective gained through speaking engagements, participation in SLA and IATUL.

o! Directed competency development for LANL Research Library. Competency tool allows staff to plan professional development, team leaders to select members based on skills, and leadership to identify gaps in staff expertise. Co-author of SLA’s Competencies for Information Professionals of the 21st Century, Revised edition.

o! Led multiple mentoring initiatives in SLA, was awarded SLA Rose L. Vormelker Award for “beyond exceptional services in area of mentoring students and/or working professionals.”

•! Scholarly communications o! Drive services and tools development with the philosophy of building the research carrot rather

than wielding the mandate stick. o! Member, National Science Communication Institute (nSCI) board and Member, Open Scholarship

Initiative (OSI) planning team. o! Scholarly communications speaker at library conferences and publisher meetings. o! Spearheaded creation and successful adoption of Open Access policies, LANL and Olin College.

With policies in place, facilitated membership to Coalition of Open Access Policy Institutions (COAPI) at both institutions.

o! Co-created personas for data management requirements, LANL. •! Student experience

o! Collaborate on LANL student initiatives including helping students and Post Docs understand their research impact.

o! Served diverse student communities, from largely first generation college students at Utica College to elite technical students at RPI, Olin College and LANL to MBA and business students at MIT Sloan.

o! Conceived, planned and oversaw creation of special collections at Olin College including materials samples, hand tools and realia or learning objects. Inspired by multiple intelligences and hands-on learning, each of these collections were unique in academic engineering libraries when conceived.

o! Partnered with Credo Reference to deliver pedagogy talk at International Association of University Libraries (IATUL; was International Association of Scientific and Technological University Libraries) conference in South Africa.

o! Developed and co-taught, with students, a holistic information literacy and study skills co-curricular called Lifehacks at Olin College that included segments on listening, statistics & analysis, speed-reading, sleep & relaxation as well as traditional research skills.

o! A PI on three grants at Olin College addressing complex conversations, sustainability collections and a tri-college resource platform.

o! Created multimedia instruction module at RPI. •! Commitment to building a better community

o! Support of community organizations in Santa Fe: Cooking With Kids, ARTsmart, Women’s International Study Center.

o! Co-PI on grant, Just Business: Moral Responsibility in a Global Economy. o! Co-organizer on Needham, MA Summit on Energy and the Environment. o! Member, Natick, MA Recycling Committee. o! City Club of Portland, Member, research committee on Community Policing.

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