Publications


Note: Copyrights to the following papers are held by the publishers. The PDF versions provided here are preprints. Please treat this material in a way consistent with the "fair use" provisions of appropriate copyright law.

Journal Publications

  1. C. Christoffersen, T. Ngo, R. Song, Y. Zhou, S. Pichardo, and L. Curiel, ``Quasi Class-DE Driving of HIFU Transducer Arrays,'' IEEE Transactions On Biomedical Circuits And Systems, Vol. 13, No. 1, 2019, pp. 214--224, DOI 10.1109/TBCAS.2018.2888990. Link to associated code at Code Ocean
  2. P. Luong, C. Christoffersen, C. Rossi-Aicardi and C. Dualibe, ``Nanopower, Sub-1 V, CMOS Voltage References with Digitally-Trimmable Temperature Coefficient,'' IEEE Transactions On Circuits And Systems I: Regular Papers, Vol. 64, No. 4, 2017, pp. 787--798, DOI: 10.1109/TCSI.2016.2632072
  3. C. Christoffersen, W. Wong, S. Pichardo, G. Togtema and L. Curiel, ``Class-DE Ultrasound Transducer Driver for HIFU Therapy,'' IEEE Transactions On Biomedical Circuits And Systems, Vol. 10, No. 2, April 2016, pp. 375-382. DOI 10.1109/TBCAS.2015.2406119
  4. M. Kabir, C. Christoffersen, N. Kriplani, ``Transient Simulation Based on State Variables and Waves,'', Int. Journal of RF and Microwave Computer-Aided Engineering, Vol. 21, No. 3, May 2011, pp. 314-324. DOI: 10.1002/mmce.20520
  5. Lei Zhu and Carlos E. Christoffersen, ``Transient and Steady-State Analysis of Nonlinear RF and Microwave Circuits,'' EURASIP Journal on Wireless Communications and Networking, Vol. 2006, Special Issue on CMOS RF Circuits for Wireless Applications, Article ID 32097, pp. 1-11.
  6. W. Batty, C. E. Christoffersen, A. B. Yakovlev, J. F. Whitaker, M. Ozkar, S. Ortiz, A. Mortazawi, R. Reano, K. Yang, L. P. B. Katehi, C. M. Snowden and M. B. Steer, ``Global Coupled EM-Electrical-Thermal Simulation and Experimental Validation for a Spatial Power Combining MMIC Array,'' IEEE Trans. on Microwave Theory and Techniques, Vol. 50, No. 12, December 2002, pp. 2820-2833. DOI: 10.1109/TMTT.2002.805142
  7. W Batty, C. E. Christoffersen, A. J. Panks, S. David, C. M. Snowden and M. B. Steer, ``Electro-Thermal CAD of Power Devices and Circuits with Fully Physical Time-Dependent Compact Thermal Modelling of Complex Non Linear 3-D Systems,'' IEEE Transactions on Components and Packaging Technology, Vol. 34, No. 4, December 2001, pp. 566-590. DOI: 10.1109/6144.974944
  8. C. E. Christoffersen and M. B. Steer, ``State-Variable-Based Transient Circuit Simulation Using Wavelets,'' IEEE Microwave and Guided Waves Letters, April 2001, pp. 161-163. DOI: 10.1109/7260.916330
  9. C. E. Christoffersen, U. A. Mughal and M. B. Steer, ``Object Oriented Microwave Circuit Simulation,'' Int. Journal of RF and Microwave Computer-Aided Engineering, Vol. 10, Issue 3, 2000, pp. 164-182.
  10. C. E. Christoffersen, M. Ozkar, M. B. Steer, M. G. Case and M. Rodwell, ``State variable-based transient analysis using convolution,'' IEEE Transactions on Microwave Theory and Techniques, vol. 47, June 1999, pp. 882-889. DOI: 10.1109/22.769322
  11. C. E. Christoffersen and M. B. Steer, ``Implementation of the local reference concept for spatially distributed circuits,'' Int. Journal of RF and Microwave Computer-Aided Engineering, Vol. 9, Issue 5, 1999, pp. 376-384.
  12. M. B. Steer, J. F. Harvey, J. W. Mink, M. N. Abdulla, C. E. Christoffersen, H. M. Gutierrez, P. L. Heron, C. W. Hicks, A. I. Khalil, U. A. Mughal, S. Nakazawa, T. W. Nuteson, J. Patwardhan, S. G. Skaggs, M. A. Summers, S. Wang, and A. B. Yakovlev, ``Global Modeling of Spatially Distributed Microwave and Millimeter-Wave Systems,'' IEEE Transactions on Microwave Theory and Techniques, vol. 47, June 1999, pp. 830-839. DOI: 10.1109/22.769316

Book Chapters

  1. Chapter in "Mathematics in Industry -- Scientific Computing in Electrical Engineering (SCEE 2008)", by Springer, 2010: C. Christoffersen ``Transient Analysis of Nonlinear Circuits Based on Waves,'' pp. 159-166.
    (Link to publisher site)
  2. Co-Author of Chapter in "Automatic Differentiation: Applications, Theory, and Implementations", Lecture Notes in Computational Science and Engineering Series, Springer, New York, NY, 2005: Frank P. Hart, Nikhil Kriplani, Sonali Luniya, Carlos E. Christoffersen and Michael B. Steer, "Streamlined Circuit Device Model Development with Freeda and ADOL-C", pp. 295--308.
    (Link to publisher site)

Conference Publications

  1. Carlos Christoffersen, Thinh Ngo, Ruiqi Song, Yushi Zhou, Samuel Pichardo, Laura Curiel ``Suboptimal Class DE Operation for Ultrasound Transducer Arrays,'' Proceedings of the 2018 IEEE NEWCAS Conference, Montreal, June 2018, pp. 1-4. DOI: 10.1109/NEWCAS.2018.8585596
  2. R. Song, C. Christoffersen, Samuel Pichardo, Laura Curiel , `` An integrated full-bridge Class-DE ultrasound transducer driver for HIFU applications,'' Proceedings of the 2016 IEEE NEWCAS Conference, Vancouver, June 2016, pp. 1-4. DOI: 10.1109/NEWCAS.2016.7604776
  3. P. Luong, C. Christoffersen, C. Rossi-Aicardi and C. Dualibe, ``Sub-1 V, 4 nA CMOS Voltage References with Digitally-Trimmable Temperature Coefficient,'' Proceedings of the 2014 IEEE NEWCAS Conference, Trois Rivieres, June 2014, pp. 345-348. DOI: 10.1109/NEWCAS.2014.6934053
  4. W. Wong, C. Christoffersen, Samuel Pichardo, Laura Curiel , ``An Integrated Ultrasound Transducer Driver For HIFU Applications,'' Proceedings of the 2013 IEEE Canadian Conference on Electrical and Computer Engineering, Regina, May 2013. DOI: 10.1109/CCECE.2013.6567791
  5. M. Kabir, C. Christoffersen, ``Wave-Based Transient Analysis Using Block Newton-Jacobi,'' Proceedings of the 2011 IEEE Canadian Conference on Electrical and Computer Engineering, Niagara Falls, May 2011, pp 669-673. DOI: 10.1109/CCECE.2011.6030537
  6. C. E. Christoffersen, G. Toombs and A. Manzak, ``An Ultra-Low Power CMOS PTAT Current Source,'' Proceeedings of the Argentine-Uruguay Conference on Micro-Nanoelectronics, Technology and Applications, October 7-8 2010, Montevideo, Uruguay, pp. 35-40. URL
  7. C. E. Christoffersen ``Transient Analysis of Nonlinear Circuits Based on Waves,'' Proceeedings of the 7th International Conference on Scientific Computing in Electrical Engineering (SCEE 2008), September 28 - October 3 2008, Helsinki Institute of Technology, Finland.
  8. C. E. Christoffersen, M. Condon and T. Xu, ``A new method for the determination of the locking range of oscillators,'' Proceeedings of the 2007 European Conference on Circuit Theory and Design (ECCTD07), Seville, August 2007, pp. 575-578. DOI: 10.1109/ECCTD.2007.4529661
  9. Zhou Wang and Carlos Christoffersen, ``Steady-State Analysis of Circuits with Multiple Adaptive Grids,'' 2007 IEEE Canadian Conference on Electrical and Computer Engineering Digest, Vancouver, April 2007. DOI: 10.1109/CCECE.2007.34
  10. S. Luniya, W. Batty, V. Caccamesi, M. Garcia, C. Christoffersen, S. Melamed, W. R. Davis and M. Steer, "Compact Electrothermal Modeling of an X-band MMIC," 2006 IEEE Int. Microwave Symp. Digest, June 2006, pp. 651-654. DOI: 10.1109/MWSYM.2006.249698
  11. C. Christoffersen, "Implementation of Exact Sensitivities in a Circuit Simulator Using Automatic Differentiation", 20th European Conference on Modelling and Simulation, May 2006, pp. 238-243.
  12. M. B. Steer, N. M. Kriplani, S. Luniya, F. Hart, J. Lowry and C. Christoffersen ``fREEDA: An Open Source Circuit Simulator,'' 2006 International Workshop on Integrated Nonlinear Microwave and Millimeter-Wave Circuits, pp. 112-115. DOI: 10.1109/INMMIC.2006.283523
  13. Lei Zhu and Carlos Christoffersen, ``Adaptive Harmonic Balance Analysis of Oscillators using Multiple Time Scales,'' 3rd International IEEE Northeast Workshop on Circuits and Systems Digest, June 2005, pp. 187-190. DOI: 10.1109/NEWCAS.2005.1496738
  14. Lei Zhu and Carlos Christoffersen, ``Fast Transient Analysis of Oscillators using Multiple Time Scales with Accurate Initial Conditions,'' 2005 IEEE Canadian Conference on Computer and Electrical Engineering Digest, Saskatoon, May 2005, pp. 700-703. DOI: 10.1109/CCECE.2005.1557030
  15. Sonali Luniya, Michael B. Steer and Carlos Christoffersen, "High Dynamic Range Transient Simulation of Microwave Circuits," 2004 IEEE Radio and Wireless Conference Digest, September 2004, pp. 487-490. DOI: 10.1109/RAWCON.2004.1389183
  16. Frank P. Hart, Nikhil Kriplani, Sonali Luniya, Carlos E. Christoffersen and Michael B. Steer, "Streamlined Circuit Device Model Development with Freeda and ADOL-C," 4th International Conference on Automatic Differentiation, Chicago, USA, July 2004.
  17. Carlos Christoffersen and Jude Alexander, ``An Adaptive Time Step Control Algorithm For Nonlinear Time Domain Envelope Transient,'' 2004 IEEE Canadian Conference on Electrical and Computer Engineering Digest, Niagara Falls, May 2004, pp. 0883-0886. DOI: 10.1109/CCECE.2004.1345256
  18. C. Christoffersen, S. Velu and M. B. Steer, `` A Universal Parameterized Nonlinear Device Model Formulation for Microwave Circuit Simulation,'' 2002 IEEE Int. Microwave Symp. Digest, June 2002, pp 2189-2192. DOI: 10.1109/MWSYM.2002.1012306
  19. W. Batty, C. E. Christoffersen, A. B. Yakovlev, J. F. Whitaker, M. Ozkar, S. Ortiz, A. Mortazawi, R. Reano, K. Yang, L. P. B. Katehi, C. M. Snowden and M. B. Steer, ``Global Coupled EM-Electrical-Thermal Simulation and Experimental Validation for a Spatial Power Combining MMIC Array,'' 2002 IEEE Int. Microwave Symp. Digest, June 2002, pp. 2177-2180. DOI: 10.1109/MWSYM.2002.1012303
  20. M. B. Steer, C. Christoffersen, S. Velu and N. Kriplani, ``Global Modeling of RF and Microwave Circuits,'' Mediterranean Microwave Conf. Digest, June 2002.
  21. W. Batty , C. E. Christoffersen, C. M. Snowden and M. B. Steer, `` Fully Physical Coupled Electro-Thermal Modelling of Power Devices and Circuits,'' PSSD conference Digest, Ilkley, UK, March 2002.
  22. C. E. Christoffersen and M. B. Steer, ``Comparison of Wavelet- and Time-Marching-Based Microwave Circuit Transient Analyses ,'' 2001 IEEE Int. Microwave Symp. Digest, May 2001, pp. 447-450. DOI: 10.1109/MWSYM.2001.966927
  23. M. B. Steer and C. E. Christoffersen, ``Generalized circuit formulation for the transient simulation of circuits using wavelet, convolution and time-marching techniques ,'' Proc. of the 15th European Conference on Circuit Theory and Design, Aug 2001, pp. 205-208.
  24. W. Batty, C. E. Christoffersen, S. David, A. J. Pan ks, R. G. Johnson, C. M. Snowden and M. B. Steer, ``Global Electro-thermal CAD of Complex Non Linear 3-D Sy stems Based on a Fully Physical Time-dependent Compact Thermal Model,'' 2001 IEEE Int. Microwave Symp. Digest, May 2001, pp. 667-670. DOI: 10.1109/MWSYM.2001.966982
  25. W. Batty, C. E. Christoffersen, S. David, A. J. Panks, R. G. Johnson, C. M. Snowden and M. B. Steer, ``Fully physical, time-dependent thermal modelling of complex 3-dimensional systems for device and circuit level electro-thermal CAD'' (extended abstract), Semi-Therm XVII, San Jose, March 2001.
  26. W. Batty, C. E. Christoffersen, S. David, A. J. Panks, R. G. Johnson, C. M. Snowden and M. B. Steer, ``Predictive microwave device design by coupled electro-thermal simulation based on a fully physical thermal model'' (extended abstract), EDMO 2000, Glasgow UK, November 2000. DOI: 10.1109/EDMO.2000.919042
  27. W. Batty, C. E. Christoffersen, S. David, A. J. Panks, R. G. Johnson, C. M. Snowden and M. B. Steer, ``Steady-state and transient electro-thermal simulation of power devices and circuits based on a fully physical thermal model,'' THERMINIC 2000 Digest, Budapest, September 2000.
  28. C. E. Christoffersen and M. B. Steer, ``Transient analysis of a spatial power combining amplifier,'' 1999 IEEE Int. Microwave Symp. Digest, June 1999, pp. 791-794. DOI: 10.1109/MWSYM.1999.779878
  29. H. Gutierrez, C. E. Christoffersen and M. B. Steer, ``An integrated environment for the simulation of electrical, thermal and electromagnetic interactions in high-performance integrated circuits,'' Proc. IEEE 6th Topical Meeting on Electrical Performance of Electronic Packaging, Sept. 1999. DOI: 10.1109/EPEP.1999.819229
  30. C. E. Christoffersen, M. B. Steer and M. A. Summers, ``Harmonic balance analysis for systems with circuit-field interactions,'' 1998 IEEE Int. Microwave Symp. Digest, June 1998, pp. 1131-1134. DOI: 10.1109/MWSYM.1998.705193
  31. M. A. Summers, C. E. Christoffersen, A. I. Khalil, S. Nakazawa, T. W. Nuteson, M. B. Steer and J. W. Mink, ``An integrated electromagnetic and nonlinear circuit simulation environment for spatial power combining systems,'' 1998 IEEE Int. Microwave Symp. Digest, June 1998, pp. 1473-1476. DOI: 10.1109/MWSYM.1998.700653
  32. M. B. Steer, C. E. Christoffersen, H. Gutierrez, S. Nakazawa, M. Abdulla, and T. W. Nutesson, ``Modelling of Large Non-Linear Systems Integrating Thermal and Electromagnetic Models,'' European Gallium Arsenide and related III-V Compounds Application Symposium, October 1998, pp. 169-174.
  33. M. B. Steer, M. Ozkar, and C. E. Christoffersen, ``Circuit level modelling of spatially distributed mm and sub mm-Wave Systems,'' Proc. 1998 IEEE Sixth Int. Conf. on Terahertz Electronics Proceedings, September 1998, pp. 21-24. DOI: 10.1109/THZ.1998.731654
  34. M. B. Steer, M. N. Abdulla, C. E. Christofersen, M. Summers, S. Nakazawa, A. Khalil and J. Harvey, ``Integrated Electromagnetic and Circuit Modeling of Large Microwave and Millimeter-Wave Structures,'' IEEE AP-S, June 1998.
  35. F. Nusseibeh, T. W. Nuteson, J. Patwardhan, M. A. Summers, C. E. Christoffersen, J. Kreskovsky, and M. B. Steer, ``Computer Aided Engineering Environment for Spatial Power Combining Systems,'' IEEE MTT-S Int. Microwave Symp. Dig., pp.~1073-1076, June 1997. DOI: 10.1109/MWSYM.1997.602987
  36. J.F. Harvey, T.W. Nuteson, J. Patwardhan, M.A. Summers, C.E. Christoffersen, F. Nusseibeh, J. Kreskovsky, and M.B. Steer, ``A Unified Electromagnetic, Nonlinear Circuit, and Thermal Analysis for Complex Spatial Power Combining Architectures,'' Proc. WRI Int. Symp. on Directions for the next Generation of MMIC Devices and Systems, June 1997.
  37. C. E. Christoffersen, L. A. Lahoz and M.I Schiavon, ``Extracción de los Elementos Parásitos de un Circuito Integrado a Partir del Layout'' (Integrated circuit parasitic elements extraction from the layout, in Spanish), Segundo Simposio de Microelectrónica, Rosario, 9 y 10 de noviembre de 1995.
  38. C. . E. Christoffersen, L. A. Lahoz and M.I Schiavon, ``Detección de los Transistores de un Circuito Integrado a Partir del Layout'' (Integrated circuit transistors detection from the layout, in Spanish), Terceras Jornadas de Investigación de las Universidades del Grupo de Montevideo, Concordia - Salto, 27, 28 y 29 de septiembre de 1995.

Thesis Reports

  1. C. E. Christoffersen, ``Global Modeling of Nonlinear Microwave Circuits,'' Ph.D. Dissertation, North Carolina State University, 2000.
  2. C. E. Christoffersen, ``State variable harmonic balance simulation of a quasi-optical power combining system,'' Master's thesis, North Carolina State University, 1998.
  3. C. E. Christoffersen, ``Programa Estimador de Parametros de Transistores Bipolares y de Efecto de Campo de Juntura'' (Program to estimate parameters for BJTs and FETs, in Spanish), Proyecto final de ingeniería, Universidad Nacional de Rosario, 1993.

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Last Updated: 07/2022