S.B. Makarov1, R.A. Davtyan2, A.K. Aharonyan3, M.V. Markosyan4, V.H. Avetisyan5, 

S.V. Zavjalov6, S.V. Tomashevich7

1,5,6 Peter The Great St. Petersburg Polytechnic University (Saint-Petersburg, Russia)

2−5 Russian-Armenian University

2−5 Yerevan Telecommunication Research Institute CJSC

7 St. Petersburg State University of Telecommunications n.a. prof. M.A. Bonch-Bruevich (St. Petersburg, Russia)

The development of communication systems, radar, radio navigation, sensing and passive radio imaging in recent years has led to the intensive mastering of the millimeter wavelength (MW) range. The listed systems contain antennas, the knowledge and determination of characteristics of which is very important for assessing the efficiency of specific system work. One of the methods for determining the characteristics of antennas is a progressive method of near-field antenna measurements by means of automatic measuring complexes (AMC).

The accuracy of further reconstruction of the far-field parameters of the test antennas (TA) abuts in the correct measurement and in their near-field distribution measurement with sufficient accuracy Therefore, the mobile line that transmits the signal through the section from the stationary equipment to the scanned along the plane probe or vice versa (depending on the operating mode of the TA) must have sufficient stability of the transfer characteristics by amplitude and by phase. Unlike the centimeter wavelength (CW) range, where there are phase-stable transmitting coaxial cables, the absence of such in the MW range requires new approaches to the design of a transmission line with similar characteristics. The implementation of the MW range AMC, due to the shortening of the operating wavelength of the TA by approximately an order of magnitude in comparison with the CW, also faces the task of ensuring the necessary positioning accuracy of the scanned measuring probe during measurements. 

The purpose of the work is to build a mobile quasi-optical waveguide signal transmission line of the MW range that is constant in geometrical length and stable in transfer characteristics by amplitude and by phase. 

The design and physical principles of operation of such a universal quasi-optical mobile transmission line are described. The transmission line is placed on a mechanical scanner together with two pantographs and acts synchronously with the scanner during scanning of the test probe when measuring the field distribution on the plane. The line contains two quasi-optical waveguide trombones, acting alternately with mutually-perpendicular movements of the test measuring probe. The knee of each trombone moves in a 1:2 ratio relative to its movable waveguide and thas the geometrical length of the transmission line is unchanged. This mutual movement is ensured by the marked pantographs. Such a combined system, consisting of a scanner and a transmission line, is intended for measuring the MW range field distribution at the nodes of a rectangular grid of coordinates on a plane. The proposed system can be used in the AMC to determine the characteristics of the MW range TA by measuring their near field. For the scanning area 1 1× m of the test probe the features of the design of the scanner, transmission line and pantograph are considered. 

The proposed design of the transmission line and the scanner serves as the basis for the manufacture of such a system. A further goal is researching of the accuracy of mechanical simultaneous compensation of the geometric length change in the mobile transmission line at keeping its length unchanged during the scanning of the probe within the intended area L2 =1 1× m of the measurement plane. At the same time, under these conditions, it is also planned to research the stability of the transfer characteristics of such a transmission line by amplitude and by phase.

Makarov S.B., Davtyan R.A., Aharonyan A.K., Markosyan M.V., Avetisyan, V.H., Zavjalov S.V., Tomashevich S.V. Movable quasi-optical signal transmission line as part of a scanner for planar field measurements of millimeter wave range. Radiotekhnika. 2021. V. 85.  № 11. P. 107−116. DOI: https://doi.org/10.18127/j00338486-202111-16 (In Russian)

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