TECHNICAL MECHANICS
ISSN (Print): 1561-9184, ISSN (Online): 2616-6380

HOME    ABOUT THIS JOURNAL    EDITORIAL BOARD    GUIDE FOR AUTHORS    CURRENT    JOURNAL ISSUES    CONTACTS

UDC 621.002.56

Technical mechanics, 2019, 3, 88 - 97

TWO-PROBE MEASUREMENTS OF THE DISPLACEMENT OF AN OBJECT WITH ACCOUNT FOR THE ANTENNA REFLECTION COEFFICIENT

DOI: https://doi.org/10.15407/itm2019.03.088

Pylypenko O. V., Doronin A. V., Gorev N. B., Kodzhespirova I. F.

Pylypenko O. V.
Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine

Doronin A. V.
Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine

Gorev N. B.
Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine

Kodzhespirova I. F.
Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine

      This paper addresses the problem of displacement measurement by microwave interferometry at an unknown target reflection coefficient in the case where that reflection coefficient is comparable with the reflection coefficient of the antenna. The aim of this paper is to propose a two-probe displacement measurement method that would account for the antenna reflection coefficient. This aim is achieved by using expressions for the quadrature signals and an equation in the unknown magnitude of the target reflection coefficient written for the case of a nonzero antenna reflection coefficient. The unknown magnitude of the target reflection coefficient is taken to be equal to the smaller positive root of that equation. If the magnitude of the target reflection coefficient is smaller than a critical value, which depends on the antenna reflection coefficient, then, theoretically, the target displacement is determined exactly; otherwise, the displacement determination error does not exceed several percent of the free-space operating wavelength. Depending on the phase of the antenna reflection coefficient, the error may be greater or smaller than in the case of a zero antenna reflection coefficient where the worst-case error is about 4.4 % of the free-space operating wavelength. To verify the proposed method, the determination of the relative displacement of a target executing a harmonic vibratory motion was simulated. In doing so, variations of the detector currents from their theoretical values were modeled by random current noise. The simulation results show that ignoring the reflection coefficient of the antenna when it is comparable with that of the target may introduce a sizeable error. The two-probe displacement measurement method proposed in this paper may be used in the development of microwave displacement sensors.
     

complex reflection coefficient, displacement, electrical probe, microwave interferometry, semiconductor detector, waveguide section

1. Viktorov V. A., Lunkin B. V., Sovlukov A. S. Radio Wave Measurements of Process Parameters. Moscow: Energoatomizdat, 1989. 208 pp. (in Russian).

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

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

4. Cripps S. C. Microwave bites - VNA tales. IEEE Microwave Magazine. 2007. V. 8. No. 5. Pp. 28-44. https://doi.org/10.1109/MMM.2007.904719

5. Andreev M. V., Drobakhin O. O., Saltykov D. Yu. Techniques of measuring reflectance in free space in the microwave range. Proceedings of the 2016 9th International Kharkiv Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves (MSMW), Kharkiv, Ukraine, June 20-24, 2016. Pp. 1-3. https://doi.org/10.1109/MSMW.2016.7538213

6. Andreev M. V., Drobakhin O. O., Saltykov D. Yu. Complex reflection coefficient determination via digital spectral analysis of multiprobe reflectometer output signals. Proceedings of the 2017 IEEE First Ukraine Conference on Electrical and Computer Engineering (UKRCON), Kyiv, Ukraine, May 29 - June 2, 2017. Pp. 170-175. https://doi.org/10.1109/UKRCON.2017.8100468

7. Pylypenko O. V., Gorev N. B., Doronin A. V., Kodzhespirova I. F. Ðhase ambiguity resolution in relative displacement measurement by microwave interferometry. Teh. Meh. 2017. No. 2. Pp. 3-11.

8. Pylypenko O. V., Doronin A. V., Gorev N. B., Kodzhespirova I. F. Experimental verification of a two-probe implementation of microwave interferometry for displacement measurement. Teh. Meh. 2018. No. 1. Pp. 5-12.

9. Doronin A. V., Gorev N. B., Kodzhespirova I. F., Privalov E. N. Displacement measurement using a two-probe implementation of microwave interferometry. Progress in Electromagnetics Research C. 2012. V. 32. Pp. 245-258. https://doi.org/10.2528/PIERC12071805

10. Doronin A. V., Gorev N. B., Kodzhespirova I. F., Privalov E. N. A way to improve the accuracy of displacement mreasurement by a two-probe implementation of microwave interferometry. Progress in Electromagnetics Research M. 2013. V. 30. Pp. 105-116. https://doi.org/10.2528/PIERM13020504

11. Silvia M. T., Robinson E. A. Deconvolution of Geophysical Time Series in the Exploration for Oil and Natural Gas. Amsterdam-Oxford-New York: Elsevier Scientific Publishing Company, 1979. 447 pp.

12. Pylypenko O. V., Doronin A. V., Gorev N. B., Kodzhespirova I. F. Analysis of the possibility of accounting for the antenna reflection coefficient in displacement measurements by probe methods. Teh. Meh. 2019. No. 1. Pp. 85-93.

DOI: https://doi.org/10.15407/itm2019.03.088

Copyright (©) 2019 Pylypenko O. V., Doronin A. V., Gorev N. B., Kodzhespirova I. F.

Copyright © 2014-2019 Technical mechanics