Tutorials

Tutorial (1)

Title: New and Efficient Techniques to Predict Radar Cross Section of Ship-like objects

Speaker: Prof. Sadasiva M Rao

Prof. Sadasiva M Rao

Affiliation: Naval Research Laboratory Washington D.C, USA

Abstract In this tutorial, we present a new method of moments (MOM) algorithm for the prediction of radar cross section (RCS) of Navy ships, subsystems, ship-board antennas, and other large objects. The tutorial begins by exploring the conventional MOM algorithm for arbitrarily shaped perfectly conducting (PEC) bodies via planar triangular patches using Rao-Wilton-Glisson (RWG) functions. For electrically large objects, the number of RWG functions can be very large, well over a million. Hence, the storage and solution times are beyond the capabilities of present day computers. To overcome this limitation, we develop a new procedure wherein the computer storage and CPU times are drastically reduced without sacrificing the advantages of MOM. The first step involves geometry processing as in conventional MOM solution. The next step involves gathering the basis functions into a small number of groups with size equal to M basis functions; thereby, casting the moment matrix into a collection of sub-matrices representing self- and mutualinteraction between the groups. In this scheme M is much smaller than N. Then, the third step involves of making two immediate neighbors to zero in any selected group, which means decoupling the near-field interaction. The procedure to achieve this goal and advantages provided by such a scheme, along with several numerical results, are discussed in detail.

Biography of the Speaker: Sadasiva M. Rao received the Bachelors from Osmania University in 1974, Masters from Indian Institute of Sciences in 1976, and Ph.D. degree with specialization in electromagnetic theory from University of Mississippi in 1980. He served as an Assistant Professor at Rochester Institute of Technology from 1980 to 1985, Senior Scientist at Osmania University from 1985 to 1987, and as a Professor in the Department of Electrical and Computer Engineering, Auburn University from 1988 to 2009. Presently, he is with the Radar Division, Naval Research Laboratory, Washington, DC. Dr. Rao is well known in the electromagnetic engineering community. He is an IEEE Fellow, included in the Thomson Scientifics’ Highly Cited Researchers List, and received the prestigious Best Paper research award from the SUMMA foundation, awarded only once every three years for published research.

Tutorial (2)

Title: Stochastic Method For Solving Certain EM Field Computation Problems

Speaker: Prof. Ramakrishna Janaswamy

Prof. Ramakrishna Janaswamy

University of Massachusettes, Amherst, USA

 
 

Abstract Stochastic method, wherein the solution of a boundary value problem in electrostatics or electrodynamics is represented as an ensemble average of a stochastic process generated by the underlying partial differential equation, is very attractive in electromagnetics because (i) it permits the solution in any subregion of a computational domain without having to determine the field everywhere, (ii) the solution is amenable to complete parallelization, and (iii) the solution can be generated without an explicit mesh. We discuss here the basics of the stochastic formulation and apply the method to the solution of Poisson’s equation and the Helmholtz equation. The latter will involve examples below the first resonance for normal media and for any frequency in plasmonic media.

Biography Of The Speaker: Ramakrishna Janaswamy is a Professor in the Department of Electrical & Computer Engineering, University of Massachusetts, Amherst. His research interests include deterministic and stochastic radio wave propagation modeling, analytical and computational electromagnetics, antenna theory and design, and wireless communications. He is Fellow of IEEE and an elected member of U.S. National Committee of International Union of Radio Science, Commissions B and F. He is a recipient of the R. W. P. King Prize Paper Award of the IEEE Transactions on Antennas and Propagation and the IEEE 3rd Millennium Medal. He served as an Associate Editor of Radio Science, the IEEE Transactions on Vehicular Technology, the IEEE Transactions of Antennas and Propagation and the IET Electronics Letters. He is an IEEE Standards Activity member representing the IEEE Antennas and Wave Propagation Standards. He is the author of the book Radiowave Propagation and Smart Antennas for Wireless Communications, Kluwer Academic Publishers, November 2000, and a contributing author in Handbook of Antennas in Wireless Communications, L. Godara (Ed.), CRC Press, August 2001 and Encyclopedia of RF and Microwave Engineering, John Wiley and Sons, 2005.

Tutorial (3)

Applications

Title: Recent Advancements in Small Antenna Designs for Laptop Applications

Speaker: Prof. Chow-Yen-Desmond Sim

Prof.Chow-Yen-Desmond Sim

Dept. of Electrical Engineering

Feng Chia University, Taichung, Taiwan

Abstract of the Tutorial This tutorial will introduce several recent design developments for small antennas working in the WLAN bands for laptop or tablet applications. The latest advancements for achieving desirable dual-/triple-band or broadband performances for these small antennas will be highlighted with examples working in the WLAN 2.4GHz and WLAN 5.2/5.8GHz bands, and a variety of design solutions for improving the impedance bandwidth and attaining the required resonance frequencies will also be discussed. In addition to that, the impacts of loading several small WLAN antennas into a real laptop computer will be introduced, and the techniques to regain the resonance frequencies of these small antennas will be demonstrated with experimental results. Lastly, this tutorial will also feature a very small planar size (7.7 mm × 5.4 mm) dual-band WLAN antenna that has exhibited reduced ground current effect. The advantages of possessing this reduced ground effect, as well as the background to achieve this effect will be highlighted with experimental results showing an unaffected performances when the antenna is loaded into a real laptop computer.

Biography of the Speaker:

Prof. Chow-Yen-Desmond Sim received his Ph.D from the Radio System Group, Engineering Department, at University of Leicester, United Kingdom, in July 2003. He is now a Distinguished Professor of the Department of Electrical Engineering, Feng Chia University, Taichung, Taiwan. He is the Executive Officer of Master's Program, College of Information and Electrical Engineering (Industrial R&D), Director of Intelligent IoT Industrial PhD Program, and Director of Antennas and Microwave Circuits Innovation Research Center of Feng Chia University. He is a Fellow of the Institute of Engineering and Technology (FIET), Senior Member of the IEEE Antennas and Propagation Society, and a Life-Member of Institute of Antenna Engineers of Taiwan (IAET). He has been awarded as the Top Ten Outstanding Reviewers of IEEE Antennas and Propagation Society for four years consecutively (between 2014 and 2017). He has served as the IEEE AP-S Taipei Chapter Chair (2016/01-2017/12), and he is the founding Chair of IEEE Council of RFID Taipei Chapter (since 2017/10). He is now serving as the Associate Editor of IEEE Access, IEEE Antennas and Wireless Propagation Letters, and International Journal of RF and Microwave Computer-Aided Engineering. His current research interests include small antenna, 5G antenna for mobile devices, VHF/UHF troposphere propagation, RFID/NFC antennas and applications, and wireless communications. Since 2016/10, he has been serving as the technical consultant of SAG (Securitag Assembly Group), which is one of the largest RFID tag manufacturers in Taiwan.

Tutorial (4)

Title: Planar Antennas: In Search of Cross-Polarized Radiation & Scope for Future Research

Speaker: Prof. Debatosh Guha

Prof. Debatosh Guha

Institute of Radio Physics and Electronics, University of Calcutta Centre for Research in Nanoscience and Nanotechnology, University of Calcutta Kolkata, India

Email: dguha@ieee.org

Abstract of the Tutorial I started some investigations in 2004 at the very early phase of conceiving defected ground structures (DGS) exploring the possibilities of its applications to planar antenna technologies. Intuitively I addressed cross-polarized radiations and took the challenge of minimizing the same in a circular microstrip patch. That interestingly gave some new insight and information which was first reported in AWPL, 2005. Subsequently, I worked with my research groups and gathered more amazing results for both microstrip and dielectric resonators as radiating elements. This tutorial will cover all such technical information and results with special focus to the bright future of continuing with this study by the next generation researchers.

Biography of the Speaker:

Debatosh Guha is a Professor in Radio Physics and Electronics, University of Calcutta. He is the former HAL Chair Professor of IIT Khargapur and present Head of the Radio Physics and Electronics Department, and Director of CRNN, Calcutta University. He has researched in developing microstrips and dielectric resonator antenna technologies. Defected Ground Structure (DGS) -inspired antenna is one of his major areas of contribution. Professor Guha is a Fellow of IEEE, the Indian National Academy of Engineering (INAE), National Academy of Sciences, Indian (NASI), West Bengal Academy of Science and Technology (WAST), and the Institution of Electronics and Telecommunication Engineers (IETE). He is the recipient of some notable awards which include IETE Ram Lal Wadhwa Award 2016 (New Delhi), IEEE AP-S Raj Mittra Travel Grant Award 2012 (Chicago); URSI Young Scientist Award 1996 (Lille, France); and Jawaharlal Nehru Memorial Fund Prize 1984 (New Delhi). He is Associate Editor of IEEE AP Transactions and IEEE AWPL

Tutorial (5)

Title: Antenna Fundamentals, Designs, and Applications to Satellite and Ground Systems

Speaker: Dr. Sudhakar Rao

Prof. Dr. Sudhakar Rao

Technical Fellow, Northrop Grumman Aerospace Systems

Redondo Beach, CA, US

Abstract of the Tutorial Design of antennas for practical applications needs several engineering skills such as antenna theory, RF analysis, knowledge of hardware components and their limitations, mechanical engineering, environmental qualifications, measurements, system knowledge etc. Yet, most complex designs and RF performance assessment can be completed very quickly without resorting to time-consuming analytical tools. The first part of this talk discusses antenna fundamentals, definitions of key terms, performance parameters, and their significance to spacecraft and ground systems. EIRP and G/T significance and calculation for space and earth station antennas will be presented. Engineers are often required to come-up with quick antenna trades and designs for a given set of RF requirements without performing laborious RF simulations. Design methodology and quick performance analysis will be discussed for reflector and phased array antennas with examples. The second part will focus on antenna hardware for various applications. Different types of antennas will be presented including reflectors, phased arrays, and TT&C antennas. Advantages, disadvantages, performance limitations of various antenna systems will be discussed. Feed systems and components needed for these antennas will be presented with examples. Use of multiple beam antennas to increase the satellite capacity and associated frequency re-use concepts will be outlined. Large antennas used for earth-stations, radio astronomy and gateway links are discussed with critical performance parameters, RF design, and hardware examples. Test plan for qualifying the antenna hardware for space applications will be discussed. This talk will benefit young engineers, student members, academicians and industry professionals with exposure to antenna fundamentals, concepts, limitations, practical implementation of designs into antenna hardware, and qualification required in order to meet the mission requirements.

Biography of the Speaker:

Sudhakar K. Rao received PhD in electrical engineering from Indian Institute of Technology Madras in 1980. He is currently a Technical Fellow at Northrop Grumman Aerospace Systems, Redondo Beach, CA working on advanced antenna systems for space & aircraft applications. Dr. Rao developed antenna payloads for more than 70, authored over 170 technical papers and holds 46 U.S patents. He authored and co-edited three text book volumes on “Handbook of Reflector Antennas and Feed Systems” published by the Artech House. He is an IEEE Life Fellow and a Fellow of IETE. Dr. Rao received several awards and recognitions that include 2002 Boeing’s Special Invention Award for series of patents on satellite antenna payloads, IEEE Benjamin Franklin Key Award in 2006, Delaware Valley Engineer of the Year in 2008, and Asian American Engineer of the year award in 2008. He received IEEE Judith Resnik Technical Field Award in 2009 for pioneering work in aerospace engineering. He is the recipient of the IETE’s 2015 Prof. S.N. Mitra Memorial award and the Distinguished Alumni Professional Achievement Award from NIT, Warangal, India in 2016. Dr. Rao recently received IEEE Region 6 Outstanding Engineer Award for 2017 and the 2017 Northrop Grumman’s President Award for innovations. Dr. Rao served as the Distinguished Lecturer by the IEEE APS during 2014-2016 and he was the AdCom member for IEEE APS during 2011-2013. He was the Chair for the IEEE APS “Industry Initiatives Committee” during 2011-2015, IEEE APS Fellow Evaluation Committee member from 2015, Associate Editor for the IEEE Antennas & Propagation Magazine, IEEE Transactions on Antennas & Propagation and IEEE AWPL, Special Session Organizer/Chair for the last six IEEE APS/URSI Symposia, and Technical Program Committee member for IEEE APS/URSI Symposia since 2004. He is one of the three founding members of InCAP and is the IEEE APS Liaison for InCAP

Tutorial (6)

Title: Electromagnetically Induced Transparency (EIT) and its potential applications in E-field Sensing

Speaker:Dr. Dubey

Prof. Dr. Dubey

Abstract of the Tutorial In the field of electromagnetic measurements, the accuracy in the measurement of E-field amplitude plays a crucial role in the determination of many other parameters such as Specific Absorption Rate (SAR) in biomedical application, EMI/EMC testing of RF and electronic devices, non-invasive RF based detection and diagnostic medical devices, etc. With the rise in the need for precise and accurate measurement of E-field amplitude, arises the need for the new technique to realize the amplitude flawlessly. The lack of traceability in the RF E-field strength measurements has been a major source of errors throughout the years and limits the growth of research works requiring impeccable measurements. Moreover, till now we don’t have the E-field sensors which work in the Infrared region clearly showing the measurable gap in the electromagnetic spectrum. Atom-based metrology standards have been widely accepted in the recent past for a number of measurements namely length, time, and frequency. The present calibration process of the E-field probes poses indirect and complex traceability path thus making it a very challenging task to perform. To calibrate them one need a known field in the testing room and to ensure the field in the room one again need a probe to read it. To overcome this dilemma during the calibration process, research work is going on to realize the RF E-field strength measurement through the atomic transitions based approach. This novel technique is based on the interaction of the highly excited alkali atoms with RF energy and utilizes the concepts of quantum interference phenomena like EIT and ATS. Under this technique, a cell containing vapors of alkali atoms is a possible candidate for a broadband probe scanning from RF to Infrared region. The present E-field probes can sense the E-field strength of approximately 100mV/m, but with the atom-based quantum E-field metrology technique the probe can sense as low as 1 µV/m of field strength with sensitivity of 1 µV m-1 Hz-1/2 . Moreover, this technique may be used to sense and measure the frequencies up to the terahertz range. Before carrying out experimental observations one should conceive a thorough physical understanding, and should be able to distinguish between the two similar looking phenomena with ease.

Biography of the Speaker:

Satya Kesh Dubey received his Ph.D. in 2010 in Engineering from Allahabad University. Currently he is Scientist in Microwave Standards, National Physical Laboratory, New Delhi. His research interests continue to be in Precision microwave measurements for Specific Absorption Rate (SAR), Radiated Power Density, Attenuation and S-parameters along with EM Wave Analysis for nano-particles. He is also working in a new atom-photon interaction based novel technique for accurate and precise E-field measurement. He has authored over 20 international peer-reviewed journals and 1 Springer brief in Electrical and Computer Engineering on “LabView based automation guide for microwave measurements. He was with National Institute of Technology (NIT), Raipur (Jan 2010 to July 2010) as Lecturer, Institute of Plasma Research (IPR), Gandhinagar (Aug. 2010 to June 2011) as Post-Doctoral Fellow, CSIR-National Aerospace Laboratories (NAL), Bengaluru (June 2011 to June 2012) as QHF Scientist Fellow. Since 2012 he has been with CSIR-National Physical Laboratory (NPL), Delhi and is working on laboratory mandate of developing and maintaining of primary standards for microwave measurements.

Tutorial (7)

Title: Overview of Multi-Mode and Hybrid-Mode Horn Antennas

Prof: Dhaval Pujara

Prof. Dhaval Pujara

Professor, Department of Electronics & Communication Engineering,

Director, Research & Innovation, Nirma University, Ahmedabad 382 481, INDIA

Email: dhaval.pujara@nirmauni.ac.in

Abstract of the Tutorial The horn antennas are widely used as primary source of illumination for reflector antennas, used in satellite communications, radio astronomy, radar, etc. Thus, the choice of horn configuration and its design decide the performance of a reflector. Some of the desired attributes of a horn antenna include, symmetric pattern in all planes, supressed side-lobes, reasonably high gain and high efficiency over a wide frequency band. The conventional pyramidal and conical horns that contain a single fundamental mode, traditionally known as pure mode horns have several limitations in form of non-symmetrical beamwidths, undesired sidelobes and low aperture efficiency. Some of these deficiencies of the pyramidal and conical horns can be overcome by multi-mode and hybrid-mode horns.

In multi-mode horns, the higher order mode(s) are added with appropriate amplitude and phase with the fundamental mode to improve the performance of the horn. On the other hand, the hybrid-mode horns are supported by the HE1n or EH1n satisfying the balanced hybrid condition and help in improving the RF performance of the overall system.

This tutorial provides an overview of the multi-mode and hybrid-mode horns. It starts with the brief history and theory of both multi-mode and hybrid-mode horns. The challenging issue of generating and adding the desired higher order modes with the fundamental mode is also addressed. A few examples of classic Potter horn, tri-mode matched feed horn, etc. are discussed with their potential applications. The second phase of the presentation covers the soft and hard horn antennas which belong to a category of hybrid-mode horn antennas. The classification and comparison of such horns are covered. Some innovative designs of hybrid-mode horns are also explained.

Biography of the Speaker:

Dhaval Pujara received B.E. degree in Electronics Engineering, M.Tech. degree in Electronics & Communications Engineering (Microwaves & Radar) from the Indian Institute of Technology (IIT), Roorkee and Ph. D. degree from Nirma University. During the year 2007-2009, he was deputed to Space Applications Centre (SAC - ISRO) for carrying out research on ‘Antennas for Satellite Applications’.

Currently, Dr. Pujara is a Professor with the Department of Electronics & Communication Engineering, Institute of Technology, Nirma University, Ahmedabad, India. He has a wide teaching experience at both the under graduate (UG) and the post graduate (PG) levels. He is also serving as a Director - Research & Innovation, Nirma University, Ahmedabad, India.

Prof. Dhaval Pujara has been awarded as the ‘Best Engineering College Teacher’ of the Gujarat state by the Indian Society for Technical Education (ISTE) in year 2004 for his outstanding contribution to the academic community and the students. He has also won ‘The Young Scientist Award’ in the year 2011 by International Union of Radio Science (URSI). In year 2015, he has been awarded with IETE - Smt. Ranjana Pal Memorial Award for his significant contribution in RF & Antennas. He has been also awarded as the Best Professor of Institute of Technology, Nirma University for year 2015. He has also received a prestigious US Fulbright Fellowship during the year 2016 to visit several Universities of the US. Recently, he has been selected for the award of ‘Academic Excellence’ by the Higher Education Forum, Mumbai.

By now, Dr. Pujara has published / presented more than 60 technical papers. He has been invited by many reputed institutes, industries to conduct the workshops/lecture series in the areas of RF and antennas. His areas of interest include antennas and RF circuit designs for space applications.

Special Sessions

Session (1)

Title: SPECIAL TOPICS ON THE THEORY AND APPLICATIONS OF ANTENNAS AND ARRAYS

Session Organizer: Prof. Prabhakar Pathak

Antennas constitute the front ends of various electromagnetic (EM) communication and sensor systems. The design of antennas typically poses many challenges as their needs continue to broaden for applications in many current and new technologies (some of which may also require the use of new materials). The performance of antennas commonly has to not only meet the required EM specifications (on gain, bandwidth, polarization, etc.) but also satisfy cost, size, weight and other constraints. Electrically small and electrically large antennas (e.g., reflector systems and lenses), respectively, pose different analysis/design challenges. Papers dealing with such challenges in various antenna applications at microwave and millimeter wave frequencies are of significant interest within this special session, along with papers on more fundamental topics related to antenna theory and design. Additionally, theoretical developments in the analysis and design of large phased arrays continue to be of growing interest for a variety of modern applications in sensor technologies. Issues of scan blindness, grating lobes, mutual coupling effects, etc. are always of interest from both a theoretical and practical standpoint. Frequency scanned arrays and sparse arrays are also of interest. Papers addressing the above fairly general topics on arrays will fit especially well within this special session. Finally, antennas and arrays need to be placed on practical platforms thus raising questions of how the complex platforms can affect the performance of such antennas and antenna arrays. Papers addressing antenna/array placement issues, and in particular conformal antennas/arrays, will also be a focus of this session.

Session (2)

ARRAY ANTENNAS

Session Organizer: Dr. Amalendu Patnaik, IIT Roorkee, India

Abstract: In modern wireless communication system, the antenna array is an integral part to achieve the spatial diversity. The demand for large array antennas exhibiting increased capabilities and reduced cost and complexity is growing day by day. In view of this increasing demand of antenna arrays in radar and communication systems, the amount of research expended on the different aspects of array technology has grown many folds, in the recent past. Few of the major topics of this technology that have been focussed in by the research community, in recent days, are (i) design of massive MIMO arrays for 5G communication and its related signal processing, (ii) development of self recoverable arrays, (iii) Innovative array structure designs. This special session will include papers in all aspects of array antennas with special emphasis on its present and future applications.

Session (3)

Title: Advances in Commercial Electromagnetic Simulation Tools

Session Organizer: Dr. C. J. Reddy

Altair Engineering, Inc, Hampton VA 23666

email: cjreddy@altair.com

Description: Commercial EM Simulations tools are being widely used by the members of Antennas and Propagation Society members. Over the past three decades these tools have matured to be reliable and productive. All of them are striving to incorporate latest developments in computational electromagnetics, such as Characteristic Mode Analysis (CMA), GPU computing, Domain Decomposition (DD), Adaptive Cross Approximation (ACA) to mention a few. Papers will be invited from the technical team members of commercial tools to present latest advancements in their tools and also from leading antenna engineers from industry who applied these tools successfully. The session will provide a forum for the conference attendees to learn new developments in commercial tools as well as their applications to solve complex engineering problems in a single session.

Session (4)

Title: Earth Station and Ground Antennas

Session Organizer: Dr. V.V. Srinivasan

ISRO, Bangalore

email: vvs.isac.gov.in

Abstract: Reflector antennas are widely used in ground stations as they have a long life time of close to 25 years. There are many advantages such as wide/multi-band, very high power up-linking, low loss, low noise temperature etc. They are exclusively used in the space industry for communicating with satellites in low earth orbits to geostationary to deep space over a range of millions of kilometers. With large number of satellites being put into orbit for various emerging and existing applications, especially at low earth orbit, at any given instant few tens of satellites are visible over a geographical location. If the health of these satellites is to be monitored, an equal number of reflector based ground stations need to be installed. Scannable multi-beam capability of antenna arrays incorporating MMIC based RF front end offers an elegant and cost effective solution to this problem. Initially, a multi panel configuration capable of supporting about 10 simultaneous beams per panel is being configured so that totally 70 satellites can be serviced at any given instant. Further receive only capability is demonstrated so that the telemetry of the spacecrafts can be monitored. The commanding requirements for the uplink with high power is envisaged with reflectors. With advanced autonomy implemented in the state of the art satellites, the commanding requirements are very minimal and multiple satellites can be obtained serially over the visibility period. Nevertheless the array based solution will have provision to upgrade with uplink capability.

Similarly beam waveguide fed large reflector antennas with diameter in excess of 32 meters is being used for deep space communications. Future requirements demand a ten-fold increase in the ground station performance which in turn calls for the usage of a 100 meter antenna system. Large reflector based solutions beyond the current diameter has high establishing cost, and demand high level of maintenance. Thanks to the power of digital processing algorithms, arrays of smaller diameter reflector can be configured to give the performance of 100 meter system. A large number (of about 100) of antennas are to be arrayed to achieve the performance. Phasing the systems for both uplink and downlink, wideband phase compensation for downlink, processing of the number of channels etc are the major challenges. Initial study of this configuration would be presented. Most of the weather radars are also based on reflector antenna and future many severe convective storms and tornadoes evolve on time scales shorter than that resolved by most mechanically scanning radar systems. A phased-array with electronically scanning, agile beam, fixed-site, S-band Doppler radar can be used to obtain rapid-scan observations of a microburst, supercells, and a tornadic supercell only for storms within ~5-km range; such resolution is needed to resolve features as small as ~1.5 km in scale (i.e., including mesocyclones and other storm-scale features). These radars implement electronic scanning in elevation while scanning mechanically in azimuth. The radar antenna is a hybrid, with pulse-to-pulse electronic elevation scanning, limited electronic azimuth scanning, and rapid mechanical azimuth scanning. Electronic scanning in elevation angle is accomplished by changing the phase delay among the antenna elements using phase shifters.

Session (5)

Title: Propagation Studies from RF to mmWaves

Session Organizer:Dr. T V C Sarma

NARL, Gadanki AP

email: tvcsarma@narl.gov.in

Abstract: E.M. wave propagation issues are at the core of spectrum and medium utilization for various scientific studies and commercial applications like atmospheric and ionospheric research, communications, navigation, remote sensing and electronic warfare. Propagation studies from underwater regions, through solid earth to the ionospheric altitudes and beyond provide valuable insights into the structure and dynamics of the medium. These studies have a direct bearing on utility, shortcomings, quality of service and commercial viability of the systems working in the respective bands.

As new innovative applications emerge, wireless capacity crunch will most likely continue leading to new imaginative methods of spectrum utilization for communications and navigation that would uncover new challenges. Modelling and experimental studies of the interaction of the e.m. waves with solid earth, atmosphere and ionosphere could be used for new remote sensing techniques like GNSS reflectometry and GNSS Radio Occultation.

Papers on recent work on propagation studies underwater, in the atmosphere, ionosphere and interplanetary space are solicited. Experimental and theoretical propagation studies with possible applications in the areas of atmospheric and ionospheric research, communications, navigation, remote sensing and electronic warfare are also welcome.

Session (6)

Title: Ultra Wideband Antennas

Special Session on: Defence Institute of Advanced Technology (DIAT)

Session Organizer: Dr. K. P. Ray

Ministry of Defence, Govt. Of India, Girinagar, Pune- 411 025

email: kpray@rediffmail.com, kpray@diat.ac.in

Abstract: There are different applications of wireless communication systems, which require an antenna element with very wide bandwidth. For example, Ultra Wide Band (UWB) wireless system, which requires ultra-wide bandwidth from 3.1 GHz to 10.6 GHz for very high-data-rate and short-range wireless communication, coding for security and low probability of interception, rejection of multi path effect, modern radar systems, etc.

Multi resonant planar and printed monopole antennas are suited for broadband and UWB wireless systems because of their wide impedance bandwidth and nearly omni-directional radiation pattern. Planar radiating monopole antenna (PRMA yields large bandwidth. In this structure only the radiating patch is planar and hence the name PRMA). Several configurations of PRMA have been reported, some of these reported configurations have bandwidth in excess of that required for UWB applications. The PRMA configurations are being fast replaced by their printed counterpart for various applications, as they are generally mounted on large ground plane, which are perpendicular to the plane of monopole (which makes them three dimensional structures). Also, the large size ground plane, similar to the case of conventional monopole antenna, limits the radiation pattern to only half hemisphere. On the other hand, printed monopole antennas are truly planar and have radiation patterns similar to that of a dipole antenna. These antennas are referred to as Printed or Planar Monopole Antenna as PMA. These monopoles are suitable for integration with other components on printed circuit board, are compact on dielectric substrate, are without backing ground plane and are very easy to fabricate. Printed antennas, commonly fabricated on FR4 substrate, are very efficient and cost effective, which is ideally suited for UWB technology based low cost systems. PRMA and PMA, both these two configurations will be addressed to distinctively and design methodologies of both these antennas will be covered in this session through invited papers from experts.