volume | PIER Journals

Abstract

This paper presents a two-probe implementation of microwave interferometry for displacement measurement at an unknown reflection coefficient. Theoretically, the proposed technique gives the exact value of the displacement for reflection coefficients (at the location of the probes) no greater r than 1/√2 and in the general case determines it to a worst-case accuracy of about 4.4% of the operating wavelength. Its experimental verification has demonstrated reasonable measurement accuracy for displacements several times as great as the operating wavelength (in real-time measurements at a free-space wavelength of 3 cm for a peak-to peak vibration amplitude of 15 cm, the maximum error in the determination of the instantaneous relative displacement and the peak-to-peak amplitude was about 3 mm and about 1 mm, respectively).

1. Cunha, A. and E. Caetano, "Dynamic measurements on stay cables of stay-cable bridges using an interferometry laser system," Experimental Techniques, Vol. 23, No. 3, 38-43, 1999.
doi:10.1111/j.1747-1567.1999.tb01570.x

2. Kaito, K., M. Abe, and Y. Fujino, "Development of a non-contact scanning vibration measurement system for real-scale structures," Structure and Infrastructure Engineering, Vol. 1, No. 3, 189-205, 2005.
doi:10.1080/15732470500030661

3. Mehrabi, A. B., "In-service evaluation of cable-stayed bridges, overview of available methods, and findings," Journal of Bridge Engineering, Vol. 11, No. 6, 716-724, 2006.
doi:10.1061/(ASCE)1084-0702(2006)11:6(716)

4. Lee, J. J. and M. Shinozuka, "A vision-based system for remote sensing of bridge displacement," NDT & E International, Vol. 39, No. 5, 425-431, 2006.
doi:10.1016/j.ndteint.2005.12.003

5. Gentile, C., "Application of microwave remote sensing to dynamic testing of stay-cables," Remote Sensing, Vol. 2, No. 1, 36-51, 2010.
doi:10.3390/rs2010036

6. Kim, S. and C. Nguyen, "A displacement measurement technique using millimeter-wave interferometry," IEEE Transactions on Microwave Theory and Techniques, Vol. 51, No. 6, 1724-1728, 2003.
doi:10.1109/TMTT.2003.812575

7. Kim, S. and C. Nguyen, "On the development of a multifunction millimeter-wave sensor for displacement sensing and low-velocity measurement," IEEE Transactions on Microwave Theory and Techniques, Vol. 52, No. 11, 2503-2512, 2004.
doi:10.1109/TMTT.2004.837153

8. Tischer, F. J., Mikrowellen-Messtechnik, Springer-Verlag, Berlin, 1958.

9. Cripps, S. C., "VNA tales," IEEE Microwave Magazine, Vol. 8, No. 5, 28-44, 2007.
doi:10.1109/MMM.2007.904719

10. Chavez, S., Q.-S. Xiang, and L. An, "Understanding phase maps in MRI: A new cutline phase unwrapping method," IEEE Transactions on Medical Imaging, Vol. 21, No. 8, 966-977, 2002.
doi:10.1109/TMI.2002.803106

11. Hasar, U. C., J. J. Barroso, C. Sabah, and Y. Kaya, "Resolving phase ambiguity in the inverse problem of reflection-only measurement methods ," Progress In Electromagnetics Research, Vol. 129, 405-420, 2012.

12. Silvia, M. T. and E. A. Robinson, Deconvolution of Geophysical Time Series in the Exploration for Oil and Natural Gas, Elsevier Scienti¯c Publishing Company, Amsterdam, Oxford, New York, 1979.

13. Okubo, Y., T. Uebo, and , "Experimental verification of measurement principle in standing wave radar capable of measuring distances down to zero meters," Electronics and Communications in Japan (Part 1: Communication), Vol. 90, No. 9, 25-33, 2007.
doi:10.1002/ecja.20375

Dr. Aleksei V. Doronin

Dr. Nikolai B. Gorev

Dr. Inna F. Kodzhespirova

Dr. Evgeny N. Privalov