Workshop on Ground, Aircraft and Satellite Antennas (25/11/2017, 3.20PM-5.00PM)
Prabhakar H. Pathak
Prof. Emeritus, The Ohio State Univ.
Adjunct Prof., Univ. of South Florida
1. Introduction to the Theory and Analysis of Conformal Phased Array Antennas:
Phased array antennas generally consist of periodically or quasi periodically spaced antenna elements which are phased to electronically scan an electromagnetic(EM) beam in a highly agile fashion. Finite planar arrays are briefly introduced and first treated via an element by element(EBE) field summation method. The presence of unwanted grating lobes is discussed and conditions for avoiding them are given. A backward fast wave is seen to exist in an example of a frequency scanned leaky waveguide array; this is in contrast to a phase scanned array. A Floquet modal analysis of infinite periodic arrays is briefly described for the approximate analysis of mutual coupling in very large finite arrays. The topics of sub arrays, grating lobes, and scan blindness effects in phased arrays are briefly discussed. An analysis of electrically large finite planar and convex arrays, which are conformal to even larger platforms, is a challenge that needs to be addressed. A uniform geometrical theory of diffraction(UTD) for treating such arrays is seen to be an attractive ray approach that is not only highly efficient as compared to the EBE field summation method, but also probably the only one that provides a vivid physical picture for the array radiation mechanisms. An efficient hybrid method is proposed for combining UTD and numerical methods for analysis of large conformal phased arrays on large complex platforms.
Bio: Prabhakar Pathak: received his Ph.D (1973) in Electrical Engineering from the Ohio State
Univ (OSU). Currently he is Professor (Emeritus) at OSU and an Adjunct Professor at the Univ.
of South Florida. Prof. Pathak is regarded as a co-developer of the uniform geometrical theory of
diffraction (UTD). His interests continue to be in the development of new UTD Ray solutions in
both frequency and time domains, as well as in the development of fast Beam and Hybrid
methods, for analyzing large electromagnetic (EM) scattering and antenna problems (e.g.
reflector systems and conformal phased arrays). His work includes the development of analytical
tools for the prediction of radiation and coupling associated with antennas/arrays placed on large
airborne, spaceborne, or other complex platforms of engineering interest. Additionally, he is
working on novel methods related to near field antenna measurements. Prof. Pathak has been
presenting short courses and invited talks at conferences and workshops both in the US and
abroad. He has authored/coauthored over a hundred journal and conference papers, as well as
contributed chapters to seven books. Prior to 1993, he served two terms as an Associate Editor of
IEEE Trans.AP-S. He was appointed as an IEEE (AP-S) Distinguished Lecturer (DL) from
1991-1993 and later appointed as the chair of the IEEE AP-S DL program during 1995 – 2005.
He was a member of the IEEE AP-S AdCom in 2010. He received the 1996 Schelkunoff best
paper award from IEEE-AP-S; the ISAP 2009 best paper award; the George Sinclair award
(1996) from OSU ElectroScience Laboratory; and, IEEE Third Millennium Medal from AP-S in
2000. Prof. Pathak received the Distinguished Achievement Award from IEEE AP-S in 2013. He
is an IEEE Life Fellow, and a member of URSI-commission B.
Dr. C.J. Reddy
2. Pushing the Boundaries of Computational Electromagnetics: Application to Airborne antennas and radomes
Advances in computational electromagnetic tools have made possible design and optimization of airborne antennas and radomes. Numerical approaches that include full-wave techniques such as Method of Moments (MoM), Multilevel Fast Multipole Method (MLFMM) and asymptotic techniques such as Physical Optics (PO) and Uniform Theory of Diffraction (UTD) are being utilized to solve many challenging problems that were not possible in the past. In this talk, an overview of various advanced numerical techniques that are useful for airborne antenna designs and placement studies will be presented. Keeping the present-day challenges in mind, a complete solution for the design and analysis of radomes, from characterizing the wall construction materials through transmission loss analysis, to the full 3D radome analysis for calculating the radome induced effects will be presented. We will also discuss the design and analysis of Frequency Selective Surface (FSS) radomes.
BIO: Dr. C.J. Reddy is the Vice President, Business Development-Electromagnetics for Americas at Altair Engineering, Inc.(www.altair.com). At Altair, he is leading the marketing and support of commercial 3D electromagnetic software, FEKO (http://www.altairhyperworks.com/product/FEKO) in Americas. Dr. Reddy is also the President of Applied EM Inc, a small company specializing in innovative antenna design and development. Dr. Reddy is a Senior Member of Institute of Electrical and Electronics Engineers (IEEE) and also a Senior Member of Antenna Measurement Techniques Association (AMTA). He has been elected Fellow of the Applied Computational Electromagnetic Society (ACES) in 2012. Dr. Reddy served on ACES Board of Directors from 2006 to 2012 and is currently serving as the Secretary of ACES. He published 37 journal papers, 77 conference papers and 18 NASA Technical Reports to date. Dr. Reddy is a co-author of the book, “Antenna Analysis and Design Using FEKO Electromagnetic Simulation Software,” published in June 2014 by SciTech Publishing (now part of IET). Dr. Reddy was the General Chair of ACES 2011 Conference held in Williamsburg, VA during March 27-31, 2011. And alsoACES 2013 conference, Monterey CA (March 24-28, 2013) as well as the General Chair of ACES 2015 conference held in Williamsburg, Virginia during March 22-26, 2015. He was the Co-General Chair of 2014 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting held during July 6-11, 2014 in Memphis, TN. Dr. Reddy is the General Chair for AMTA 2018 conference to be held in Williamsburg, Virginia during November 3-8, 2018.
Senior Engineer “Electromagnetic Engineering Division (EME)” IDS
Antenna design challenges and measurements opportunities in UAV applications.
The market of Unmanned Aerial Vehicle (UAV) is experiencing an amazing increase thanks to the number of innovative services that can be provided by means of UAV. This scenario is particularly interesting for antenna designers since it opens new challenging requirements both for the antennas to be placed on board of the vehicle and for those called to provide ground station services.
The use of UAVs is becoming more and more commonplace in both the civil and military domains. There could be opportunities for the usage of UAV by terrorist organization or simply by amateur hobbyists unaware of the regulations and potential risks.
The application of radar technology for detection and location of fixed wind and rotorcraft UAVs is, therefore, becoming of paramount importance for the protection of our communities.
Among the other applications, the usage of UAV in the field of antenna measurements and em field monitoring is also of great interests since it commits overcoming the limitation of standard measurements techniques especially for large antenna systems.
This presentation illustrates the challenges for antenna designers in UAV applications and presents some real cases matured by IDS; the results of our experiences in measurements performed by UAV will also be presented.
Education: University degree (110/110 cum laude) in Electronic Engineering from the University of Napoli, in 1995 with thesis work on Numerical methods for analysis of bifurcations and chaos in the nonlinear dynamics of transmission lines
Present position: Senior Engineer “Electromagnetic Engineering Division (EME)” at IDS.
Activities and professional experiences of interest:
Signal and Power integrity analysis at Printed Circuit Board level
EMC design best practice
RF and antenna design, EMC analysis and design for electronic systems for earth station, naval, avionic and space environments;
CAE tools design for electromagnetic applications;
Electromagnetic methods and application to industrial application: numerical methods (Method of Moments, FEM, FDTD, MTL, asymptotic methods (GTD, PO, PTD) modeling of e.m. radiation interaction with complex environments; patch array design;
Lecturer for EM simulation, Signal integrity and EMC in several Italian and international Universities
Giancarlo published original papers at international meetings and on technical journals, on topics related to his relevant experience.