volume | PIER Journals

Abstract

The paper deals with the evaluation of the far-field radiated emissions from high-speed interconnects when the frequencies are such that the distribution of the currents along the traces is no longer of TEM-type. Instead of a computationally expensive numerical full-wave model, here a generalized transmission line model is used to obtain the current distributions. This full-wave transmission line model is derived from an integral formulation and is here extended to include in efficient way the layered media Green's Functions. The proposed tool is successfully benchmarked to references given in literature and case-studies of practical interest are carried out, referring to a coupled microstrip, driven either by differential and common mode currents. This analysis highlights the existence of a transition range where the error made by evaluating the emission using the classical transmission line current distribution is still negligible. Here a rule of thumb is derived which provides a simple criterion to estimate this extension of the range of validity of the classical transmission line.

1. Paul, C. R., Introduction to Electromagnetic Compatibility, Wiley, 1992.

2. Gravelle, L. B. and P. F. Wilson, "EMI/EMC in printed circuit boards --- A literature review," IEEE TEMC, Vol. 34, 109-116, 1992.

3. Paul, C. R., "A comparison of the contributions of common-mode currents and differential-mode currents in radiated emissions," IEEE TEMC, Vol. 31, No. 2, 189-193, 1989.

4. Matias, R. M. and A. Raizer, "Calculation of electric field created by transmission lines, by 3D-FE method using complex electric scalar potential," ACES, Journal, Vol. 12, No. 1, 56-60, 1997.

5. Naishadham, K., J. B. Berry, and H. A. N. Hejase, "Full-wave analysis of radiated emission from arbitrarily shaped printed circuit traces," IEEE TEMC, Vol. 35, No. 3, 366-377, 1993.

6. Pinello, W. P., A. C. Cangellaris, and A. Ruehli, "Prediction of differential- and common-mode noise in high-speed interconnects with the partial element equivalent circuit technique," IEEE Intern. Sympos. on EMC, Vol. 2, 940-945, Aug. 1998.

7. Mosig, J., "Arbitrarily shaped microstrip structures and their analysis with a mixed potential integral equation," IEEE Trans. Microwave Theory Tech., Vol. 36, 314-323, Feb. 1988.
doi:10.1109/22.3520

8. Zhao, J. S. and W. C. Chew, "Integral equation solution of Maxwells equations from zero frequency to microwave frequencies," IEEE TAP, Vol. 48, No. 10, 1635-1645, Oct. 2000.

9. Chew, W. C., Waves and Fields in Inhomogeneous Media, IEEE Press, 1996.

10. Abdelmageed, A. K. and M. S. Ibrahim, "On enhancing the accuracy of evaluating Green's functions for multilayered media in the near-field region," Progress In Electromagnetics Research M, Vol. 2, 1-14, 2008.
doi:10.2528/PIERM08022505

11. Jerse, T. A. and C. Paul, "A hybrid method for efficient estimating common-mode radiation from transmission-line structures," Proc. of EM International Symposium Record, 145-149, Atlanta, Aug. 1995.

12. Chen, I. F., C. M. Peng, and C. W. Hsue, "Circuit-concept approach to radiated emissions of printed circuit boards," IEE Proc. Sci. Meas. Tech., Vol. 151, No. 3, 205-210, 2004.
doi:10.1049/ip-smt:20040094

13. Leone, M., "Closed-form expressions for the electromagnetic radiation of microstrip signal traces," IEEE TEMC, Vol. 49, 322-328, 2007.

14. Maffucci, A., G. Miano, and F. Villone, "Recent developments of transmission line models for interconnects," PIRES Proceedings, 97-100, Pisa, Italy, Mar. 28--31, 2004.

15. Maffucci, A., G. Miano, and F. Villone, "An enhanced transmission line model for conductors with arbitrary cross-sections," IEEE TAdvP, Vol. 28, 174-188, 2005.

16. Chiariello, A. G., A. Maffucci, G. Miano, F. Villone, and W. Zamboni, "A transmission-line model for full-wave analysis of mixed-mode propagation," IEEE TAdvP, Vol. 31, No. 2, 275-284, 2008.

17. Chiariello, A. G., A. Maffucci, G. Miano, and F. Villone, "Transmission line models for high-speed conventional interconnects and metallic carbon nanotube interconnects," Electromagnetic Field Interaction with Transmission Lines, F. Rachidie and S. Tkachenko (eds.), WIT Press, Southampton, UK, Feb. 2008.

18. Chow, Y. L., J. J. Yang, D. G. Fang, and G. E. Howard, "A closed-form spatial Green's function for the thick microstrip substrate," IEEE T-MTT, Vol. 39, 588-592, 1991.
doi:10.1109/22.75309

19. Michalski, K. A. and J. R. Mosig, "Multilayered media Green's functions in integral equation formulations," IEEE T-AP, Vol. 45, No. 3, 508-519, 1997.

20. Sharma, R., T. Chakravarty, and A. B. Bhattacharyya, "Signal integrity issues in high-speed interconnects over a ground plane aperture," Journal of Electromagnetic Waves and Applications, Vol. 22, No. 16, 2231-2240, 2008.
doi:10.1163/156939308787522500

21. Essid, C., M. B. B. Salah, K. Kochlef, A. Samet, and A. B. Kouki, "Spatial-spectral formulation of method of moment for rigorous analysis of microstrip structures," Progress In Electromagnetics Research Letters, Vol. 6, 17-26, 2009.
doi:10.2528/PIERL08112706

Dr. Andrea Gaetano Chiariello

Dr. Giovanni Miano

Dr. Antonio Maffucci