Education:
 Ph.D., Electrical Engineering, University of Illinois, UrbanaChampaign, IL, 19881991
 M.S., Electrical Engineering, University of Illinois, UrbanaChampaign, IL, 19861988
 B.S., Middle East Technical University, Ankara, Turkey
Academic Positions:
 Adjunct Professor, University of Illinois, UrbanaChampaign, IL, 2010present
 Professor, Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 20032014
 Adjunct Professor, University of Illinois, UrbanaChampaign, IL, 20052008
 Visiting Professor, University of Illinois at UrbanaChampaign, IL, 20032005
 Associate Professor, Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 19992003
 Visiting Associate Professor, University of Illinois, UrbanaChampaign, IL, 19971998
 Assistant Professor, Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 19941999
 Graduate research and teaching assistant, Department of Electrical and Computer Engineering, University of Illinois, UrbanaChampaign, IL, 19861991
Research Interests:
 Computational electromagnetics (CEM), fast solvers, parallel computing, and electromagnetic theory are Prof. Levent Gürel's main lines of research. He is interested in the development of fast algorithms for the solution of extremely large integralequation problems arising in CEM. Such a powerful computational capability is applied to the solution of problems with unprecedented complexities in the areas of electromagnetic scattering and radiation, antennas and radars, metamaterials, optical and imaging systems, frequencyselective surfaces, nanotechnology, and highspeed electronic circuits. Electromagnetic compatibility (EMC) and electromagnetic interference (EMI) are also among his research interests. Prof. Gürel is also interested in the solution of inverse problems, subsurface scattering, ground penetrating radars, and medical imaging with microwaves.
By implementing a fully parallelized version of the multilevel fast multipole algorithm (MLFMA), Prof. Gürel’s research group has been solving the world’s largest integralequation problems since 2006. Most recently, they accomplished the solution of dense matrix equations
involving as many as one billion (!) unknowns.
Selected Publications:
 W. C. Chew and L. Gürel, “Reflection and transmission
operators for strips or disks embedded in homogeneous and layered media,” IEEE Trans. Microwave Theory Tech., vol. MTT36, pp. 14881497, Nov. 1988.
 L. Gürel and W. C. Chew, “Guidance or resonance conditions for strips or disks embedded in homogeneous and layered media,” IEEE Trans. Microwave Theory Tech., vol. MTT36, pp. 14981506, Nov. 1988.
 L. Gürel and W. C. Chew, “Recursive algorithms for
calculating the scattering from N strips or patches,” IEEE
Trans. Antennas Propagat.vol. AP38, pp. 507515, Apr.
1990.
 L. Gürel and W. C. Chew, “A recursive Tmatrix algorithm
for strips and patches,” Radio Science, vol. 27,pp. 387401,
MayJune 1992.
 W. C. Chew, L. Gürel, Y. M. Wang, G. Otto, R. Wagner, and Q. H.
Liu, “A generalized recursive algorithm for wavescattering solutions in
two dimensions,” IEEE Trans. Microwave Theory Tech.,
vol. MTT40, pp.
716723, April 1992.
 W. C. Chew, Y. M. Wang, and L. Gürel, “Recursive algorithm
for using windowed addition theorem,” J. of Electromagn. Waves Appl., vol. 6,no. 11, pp. 15371560, Nov. 1992.
 L. Gürel and W. C. Chew, “Scattering solution of threedimensional array of patches using the recursive Tmatrix algorithms,” IEEE Microwave and Guided Wave Lett., vol. 2, pp. 182184, May 1992.
 L. Gürel and W. C. Chew, “Recursive Tmatrix algorithms for the solution of electromagnetic scattering from strip and patch geometries,” IEEE Trans. Antennas Propagat.,vol. AP41, pp. 9199, Jan. 1993.
 L. Gürel and M. I. Aksun, “Electromagnetic scattering solution of conducting strips in layered media using the fast multipole method,” IEEE Microwave and Guided Wave Lett. vol. 6, no. 8, pp. 277279, Aug. 1996.
 U. Oğuz and L. Gürel, “Interpolation techniques to improve the accuracy of the plane wave excitations in the finite difference time domain method,” Radio Science vol. 32, no. 6, pp. 21892199, Nov.Dec. 1997.
 L. Gürel and W. C. Chew, “Fast algorithm for scattering from planar arrays of conducting patches,” IEEE Microwave and Guided Wave Lett., vol. 8, no. 4, pp. 155157, April 1998.
 U. Oğuz, L. Gürel and O. Arıkan, “An efficient and accurate technique for the incidentwave excitations in the FDTD method,” IEEE Trans. Microwave Theory Tech., vol. 46, no. 6, pp. 869882, June 1998.
 L. Gürel, K. Sertel, and İ. K. Şendur, “On the choice of basis functions to model surface electric current densities in computational electromagnetics,” Radio Science, vol. 34, no. 6, pp. 13731387, Nov.Dec. 1999.
 L. Gürel and U. Oğuz, “Signalprocessing techniques to
reduce the sinusoidal steadystate error in the FDTD method,” IEEE
Trans. Antennas Propagat. vol. 48, no. 4, pp. 585593, April 2000.
 L. Gürel and U. Oğuz, “Threedimensional FDTD modeling
of a groundpenetrating radar,” IEEE Trans. Geosci. Remote Sensing,
vol. 38, no. 4, pp. 15131521, July 2000.
 L. Gürel and U. Oğuz, “Simulations of groundpenetrating
radars over lossy and heterogeneous grounds,” IEEE Trans. Geosci.
Remote Sensing, vol. 39, no. 6, pp. 11901197, June
2001.
 U. Oğuz and L. Gürel, “Modeling of
groundpenetratingradar antennas with shields and simulated absorbers,” IEEE
Trans. Antennas Propagat, vol. 49, no. 11, pp. 15601567, Nov. 2001.
 M. I. Aksun, F. Caliskan, and L. Gürel, “An efficient method for electromagnetic characterization of 2D geometries in stratified media,” IEEE Trans. Microwave Theory Tech., vol. 50, no. 5, pp. 12641274, May 2002.
 L. Gürel and U. Oğuz,
“Transmitterreceivertransmitter configurations of the groundpenetrating
radar,” Radio Science, vol. 37, no.3, pp. 51  57, May
2002.
 U. Oğuz and L. Gürel, "Application
of signalprocessing techniques to dipole excitations in the finitedifference
timedomain method," J. Electromagn. Waves Appl.vol.
16, no. 5, pp. 671687, May 2002.
 U. Oğuz and L. Gürel, "Frequency
responses of groundpenetrating radars operating over highly lossy grounds,"
IEEE Trans. Geosci. Remote Sensingvol. 40, no. 6, pp. 13851394, June 2002.
 L. Gürel and U. Oğuz, "Transmitterreceivertransmitterconfigured
groundpenetrating radars over randomly heterogeneous ground models,"
Radio Science, vol. 37, no. 6, pp. 61  69, Nov.Dec. 2002.
 U. Oğuz and L. Gürel, "Optimization of the
transmitterreceiver separation in the groundpenetrating radar," IEEE Trans. Antennas Propagat., vol. 51, no. 3, pp. 362370, Mar. 2003.
 L. Gürel, H. Bağcı, J. C. Castelli,
A. Cheraly, and F. Tardivel, "Validation through comparison: measurement
and calculation of the bistatic radar cross section (BRCS) of a stealth
target," Radio Science, vol. 38,
no. 3, pp. 121  1210, June 2003.
 U. Oğuz and L. Gürel, "Reducing the
dispersion errors of the finitedifference timedomain method for
multifrequency planewave excitations," Electromagnetics, vol. 23,
no. 6, pp. 539  552, Aug.Sep. 2003.
 Ö. Ergül and L. Gürel, "Nonplanar trapezoidaltooth logperiodic antennas: design and electromagnetic modelling,"
Radio Science, vol. 40, RS5010, doi:10.1029/2004RS003215, Oct. 2005.
 Ö. Ergül and L. Gürel, "Solidangle factor in the magneticfield integral equation," Microwave and Opt. Technol. Lett., vol. 45, no. 5, pp. 452456, June 2005.
 L. Gürel and Ö. Ergül, "Singularity of the magneticfield integral equation and its extraction," IEEE Antennas Wireless Propagat. Lett., vol. 4, pp. 229232, 2005.
 Ö. Ergül and L. Gürel, "Improved testing of the magneticfield integral equation," IEEE Microwave Wireless Comp. Lett., vol. 15, no. 10, pp. 615617, Oct. 2005.
 Ö. Ergül and L. Gürel, "The use of curlconforming basis functions for the magneticfield integral equation," IEEE Trans. Antennas Propagat., vol. 54, no. 7, pp. 19171926, July 2006.
 Ö. Ergül and L. Gürel, "Improving the accuracy of the magneticfield integral equation with the linearlinear basis functions," Radio Sci., vol. 41, RS4004, doi:10.1029/2005RS003307, July 2006.
 Ö. Ergül and L. Gürel, "Enhancing the accuracy of the interpolations and anterpolations in MLFMA," IEEE Antennas Wireless Propagat. Lett., vol. 5, pp. 467470, 2006.
 Ö. Ergül and L. Gürel, "Optimal interpolation of translation operator in multilevel fast multipole algorithm," IEEE Trans. Antennas Propagat., vol. 54, no. 12, pp. 38223826, Dec. 2006.
 L. Gürel and Ö. Ergül, "Extending the applicability of the combinedfield integral equation to geometries containing open surfaces," IEEE Antennas Wireless Propagat. Lett., vol. 5, pp. 515516, 2006.
 Ö. Ergül and L. Gürel, "Linearlinear basis functions for MLFMA solutions of magneticfield and combinedfield integral equations," IEEE Trans. Antennas Propagat., vol. 55, no. 4, pp. 11031110, Apr. 2007.
 T. Malas and L. Gürel, "Incomplete LU preconditioning with multilevel fast multipole algorithm for electromagnetic scattering," SIAM J. Scientific Computing, vol. 29 , no. 4, pp. 14761494, June 2007.
 Ö. Ergül and L. Gürel, "Modeling and synthesis of circularsectoral arrays of logperiodic antennas using multilevel fast multipole algorithm and genetic algorithms," Radio Science, vol. 42, RS3018, doi:10.1029/2006RS003567, June 2007.
 L. Gürel and Ö. Ergül, "Fast and accurate solutions of extremely large integralequation problems discretized with tens of millions of unknowns," Electron. Lett., vol. 43, no. 9, pp. 499500, doi:10.1049/el:20070639, Apr. 2007.
 Ö. Ergül and L. Gürel, "Efficient solution of the electricfield integral equation by the iterative LSQR algorithm," IEEE Antennas Wireless Propagat. Lett., vol. 7, pp. 3639, 2008.
 Ö. Ergül and L. Gürel, "Hierarchical parallelisation strategy for the multilevel fast multipole algorithm in computational electromagnetics," Electron. Lett., vol. 44, no. 1, pp. 35, Mar2008.
 Ö. Ergül and L. Gürel, "Stabilization of integralequation formulations for the accurate solution of scattering problems involving lowcontrast dielectric objects," IEEE Trans. Antennas Propagat., vol. 56, pp. 799805, 2008.
 Ö. Ergül and L. Gürel, "Efficient parallelization of the multilevel fast multipole algorithm for the solution of largescale scattering problems," IEEE Trans. Antennas Propagat., vol. 56, no. 8, pp. 23352345, Aug. 2008.
 Ö. Ergül and L. Gürel, "Novel electromagnetic surface integral equations for highly accurate computations of dielectric bodies with arbitrarily low contrasts," J. Comput. Phys., vol. 227, no. 23, pp. 98989912, Dec. 2008.
 L. Gürel and Ö. Ergül, "Design and simulation of circular arrays of trapezoidaltooth logperiodic antennas via genetic optimization," Prog. Electromagn. Res., PIER 85, pp. 243260, 2008.
 Ö. Ergül and L. Gürel, "Comparison of integralequation formulations for the fast and accurate solution of scattering problems involving dielectric objects with the multilevel fast multipole algorithm," IEEE Trans. Antennas Propagat., vol. 57, no. 1, pp. 176187, Jan. 2009.include/pdf_icon.png" border="0">
 T. Malas and L. Gürel, "Accelerating the multilevel fast multipole algorithm with the sparseapproximateinverse (SAI) preconditioning," SIAM J. Sci. Comput., vol. 31, no.3, pp. 19681984, March 2009.
 Ö. Ergül, I. van den Bosch, and L. Gürel, "Twostep Lagrange interpolation method for the multilevel fast multipole algorithm," IEEE Antennas Wireless Propagat. Lett., vol. 8, pp. 6971, 2009.
 Ö. Ergül and L. Gürel, "Iterative solutions of hybrid integral equations for coexisting open and closed surfaces," IEEE Trans. Antennas Propagat., vol. 57, no. 6, pp. 1751–1758, June 2009.
 Ö. Ergül and L. Gürel, "A hierarchical partitioning strategy for an efficient parallelization of the multilevel fast multipole algorithm," IEEE Trans. Antennas Propagat., vol. 57, no. 6, pp. 1740–1750, June 2009.
 L. Gürel, Ö. Ergül, A. Ünal, and T. Malas "Fast and accurate analysis of large metamaterial structures using the multilevel fast multipole algorithm," Prog. Electromagn. Res., PIER 95, pp 179198, 2009.
 L. Gürel and Ö. Ergül, "Contamination of the accuracy of the combinedfield integral equation with the discretization error of the magneticfield integral equation," IEEE Trans. Antennas Propagat., vol. 57, no. 9, pp. 2650–2657, Sept. 2009.
 Ö. Ergül and L. Gürel, "Discretization error due to the identity operator in surface integral equations," Comput. Phys. Commun., vol. 180, no. 10, pp. 17461752, Oct 2009.
 Ö. Ergül and L. Gürel, "Efficient solution of the electric and magnetic current combinedfield integral equation with the multilevel fast multipole algorithm and blockdiagonal preconditioning," Radio Science, vol. 44, RS6001, doi:10.1029/2009RS004143.
 L. Gürel and T. Malas, "Iterative nearfield preconditioner for the multilevel fast multipole algorithm," SIAM J. Sci. Comput., vol. 32, no. 4, pp. 1929–1949, 2010.
 Ö. Ergül, A. ArslanErgül and L. Gürel, "Computational study of scattering from healthy and diseased red blood cells," J. Biomed. Opt., vol. 15, no. 4, 045004, doi:10.1117/1.3467493, July/Aug. 2010.
 Ö. Ergül, T. Malas and L. Gürel, "Solutions of largescale electromagnetics problems using an iterative innerouter scheme with ordinary and approximate multilevel fast multipole algorithms," Prog. Electromagn. Res., PIER 85, vol. 106, pp. 203223, 2010.
 Ö. Ergül and L. Gürel, "Efficient solutions of metamaterial problems using a lowfrequency multilevel fast multipole algorithm," Prog. Electromagn. Res., vol. 108, no. 8199, 2010.
 Ö. Ergül and L. Gürel, "Improving iterative solutions of the electricfield integral equation via transformations into normal equations," J. of Electromagn. Waves and Appl., vol. 24, no. 16, pp. 2129–2138, Nov. 2010.
 Ö. Ergül and L. Gürel, "Rigorous solutions of electromagnetics problems involving hundreds of millions of unknowns," IEEE Antennas Propagat. Mag., vol. 53, no. 1, pp. 1827, Feb. 2011.
 Ö. Ergül, T. Malas, and L. Gürel, "Analysis of dielectric photoniccrystal problems with MLFMA and Schurcomplement preconditioners," J. Lightw. Technol., vol. 29, no. 6, pp. 888897, Mar. 2011.
 T. Malas and L. Gürel, "Schur complement preconditioners for surface integralequation formulations of dielectric problems solved with the multilevel fast multipole algorithm," SIAM J. Sci. Comput., vol. 33, no. 5, pp. 2440–2467, 2011.
 Ö. Ergül and L. Gürel, "Rigorous analysis of doublenegative materials with the multilevel fast multipole algorithm," Applied Computational Electromagnetics Society (ACES) Journal, vol. 27, no. 2, pp. 161168, Feb. 2012.
 L. Gürel and Ö. Ergül, "Hierarchical parallelization of the multilevel fast multipole algorithm (MLFMA)," IEEE Proceedings, , vol. 101, no. 2, pp. 332  341, Feb. 2013.
 Ö. Ergül and L. Gürel, "Accurate solutions of extremely large integralequation problems in computational electromagnetics," IEEE Proceedings, , vol. 101, no. 2, pp. 342  349, Feb. 2013.
 Ö. Ergül and L. Gürel, "Fast and Accurate Analysis of LargeScale Composite Structures with the Parallel Multilevel Fast Multipole Algorithm," J. Opt. Soc. Am. A, vol. 30, no. 3, pp. 509  517, March 2013.


