volume | PIER Journals

Abstract

The performance of wideband radar system may be degraded by signal distortion occurring in anyplace of the transmission channel of the system. If the amplitude response is not flat or the signal delay is not constant in the transmission of the wideband signal, then signal distortion will occur, which can reduce the SNR and resolution. The available theory indicates that a small sinusoidal ripple variation in either amplitude-frequency or phase-frequency response of a linear system will cause signal distortion and the phenomena of paired echoes in the output signals of the time domain. In this paper, whether a dispersive transmission line with discontinuities will lead to the phenomena of paired echoes is discussed by means of finite difference time domain (FDTD) method and theoretical analysis. The results show that the technique of paired echoes is unsuited to analyze the influence of dispersive transmission line with discontinuities on time domain pulse signal. The method of Taylor series expansion shall be chosen as a more appropriate method. Meanwhile, simulations also show that a pulse signal transmitting in dispersive transmission lines with discontinuities including passive components such as filters and directional couplers will not lead to the phenomena of paired echoes.

1. MacColl, L., "Discussion of paired-echo distortion analysis," Proc. IRE (Correspondence), Vol. 27, 384, June 1939.
doi:10.1109/JRPROC.1939.228449

2. Wheeler, H. A., "The interpretation of amplitude and phase distortion in terms of paired echoes," Proc. IRE, Vol. 27, 359-384, June 1939.
doi:10.1109/JRPROC.1941.231301

3. Wheeler, H. A., "The solution of unsymmetrical-sideband problems with the aid of the zero-frequency carrier," Proc. IRE, Vol. 29, 446-458, June 1941.
doi:10.1109/PROC.1969.6913

4. Bechtel, M. E., "Generalized paired-echo analysis for bandpass systems," Proceedings of IEEE, 204-205, February 1969.
doi:10.1109/PROC.1969.6913

5. Robert, S. W., "SAW diffraction analysis by paired echo superposition," IEEE Trans. on Sonics and Ultrasonics, Vol. 23, No. 4, 249-254, July 1976.
doi:10.1109/PROC.1963.1801

6. Cook, C. E., "Pulse-compression paired-echo experiments," Proceedings of IEEE, 383-384, February 1963.
doi:10.1109/PROC.1964.2927

7. Cook, C. E. and J. Paolillo, "A pulse compression predistortion function for efficient sidelobe reduction in a high-power radar," Proceedings of IEEE, 377-385, April 1964.
doi:10.1109/PROC.1964.2927

8. Wehner, D. R., High-resolution Radar, Artech House, Boston London, 1995.

9. Lynn, P . A., An Introduction to the Analysis and Processing of Signals, 2nd Ed., Macmillan, London, 1982.

10. Taflove, A., Advanced in Computational Electodynamics: The Finite-difference Time-domain Method, Artech House, Norwood, Mass., 1998.

11. Dou, W. B. and K. N. Yung, "An interesting phenomenon in the difference time domain simulation of a Gaussian pulse propagation in a waveguide," Radio Science, Vol. 36, No. 66, 1307-1314, 2001.
doi:10.1029/2000RS002354

12. Krupezevic, D. V., V. J. Brankovic, and F. Arndt, "The waveequation FDTD method for the efficient eigenvalue analysis and S-matrix computation of waveguide structures," IEEE Trans. Microwave Theory Tech., Vol. 41, 2109-2115, 1993.
doi:10.1109/22.260694

13. Collin, R. E., Field Theory of Guided Waves, Mc Graw-Hill Book Co., New York, 1960.

14. Chen, C. Z., Mathematical Analysis, Vol. 2, High Education Press, Beijing, 1983.

15. Zheng, J. L., Signal and System, Vol. 1, Higher Education Press, Beijing, 1981.

16. Collin, R. E., "Foundations for Microwave Engineering," McGraw-Hill, Inc.,, 1992.

17. Hillion, P ., "Electromagnetic pulses in dispersive media," Progress In Electromagnetics Research, Vol. 18, 245-260, 1998.
doi:10.2528/PIER97050700

18. Hillion, P ., "Electromagnetic pulse propagation in dispersive media," Progress In Electromagnetics Research, Vol. 35, 299-314, 2002.
doi:10.2528/PIER02021703

19. Wu, H. C. and W. B. Dou, "A rigorous analysis and experimental researches of waveguide magic tee at W band," Progress In Electromagnetics Research, Vol. 60, 131-142, 2006.
doi:10.2528/PIER05112904

20. Wu, H. C. and W. B. Dou, "Field structures of waveguides junction circulators with irregular shaped ferrite simulated based on exact treatment," Progress In Electromagnetics Research, Vol. 57, 33-54, 2006.
doi:10.2528/PIER05071102

21. Ho, M. and F. S. Lai, "Effects of medium conductivity on electromagnetic pulse propagation onto dielectric half space: One-dimensional simulation using characteristic-based method," Journal of Electromagnetic Waves and Application, Vol. 21, No. 13, 1773-1785, 2007.

22. Lee, J. S. and D. P. Nyquist, "The proper EM field spectra of an open integrated microstrip waveguide," Journal of Electromagnetic Waves and Application, Vol. 18, No. 12, 1605-1620, 2004.
doi:10.1163/1569393042955153

23. Fayedeh, H., C. Ghobadi, and J. Nourinia, "An improvement for FDTD analysis of thin-slot problems," Progress In Electromagnetics Research B, Vol. 2, 15-25, 2008.
doi:10.2528/PIERB07102907

Dr. Yong Feng Gui

Dr. Wen-Bin Dou