METHOD TO MEASURE COEFFICIENT OF REFLECTION OF FLAT REFLECTOR IN MICROWAVE RANGE AND DEVICE FOR ITS REALISATION

摘要

FIELD: measurement equipment.;SUBSTANCE: previously calibration is performed with the help of a flat reference reflector, then perpendicularly to the axis of the mirror in the middle of the distance L_foc between the phase centre of the radiator and the mirror focus they install a reference reflector with available coefficient of reflection of G^REF, the coefficient of reflection $S_{11}^{ref}\left(f\right)\mathop{\mathrm{image}}$ is measured in the same frequency band, and the third coefficient $A_3^{ref}\mathop{\mathrm{image}}$ of generalised polynom $P^{ref}\left(f\right)={\displaystyle \sum A_n^{ref}\exp \left(-jn2\pi f{L}_{foc}/c\right)}\mathop{\mathrm{image}}$ is determined, which approximates the difference of measured coefficients of reflection referred to the radiator aperture: $P^{ref}\left(f\right)\approx \left(S_{11}^{ref}\left(f\right)-S_{11}^{ta}\left(f\right)\right)\exp \left(j2{\phi }_{tr}\left(f\right)\right),\mathop{\mathrm{image}}$ afterwards instead of the reference reflector they install a tested reflector, the reflection coefficient is measured at the inlet of the measuring antenna $S_{11}^{tr}\left(f\right)\mathop{\mathrm{image}}$ in the same frequency band, and the third coefficient of the polynom $P^{tr}\left(f\right)={\displaystyle \sum A_n^{tr}\exp \left(-jn2\pi f{L}_{foc}/c\right)}\mathop{\mathrm{image}}$ is determined, which approximates difference of reflection coefficients $S_{11}^{tr}\left(f\right)-S_{11}^{ta}\left(f\right),\mathop{\mathrm{image}}$ referred to the $A_3^t\mathop{\mathrm{image}}$ radiator's aperture $P^{ref}\left(f\right)\approx \left(S_{11}^{tr}\left(f\right)-S^{ta}\left(f\right)\right)\exp \left(j2{\phi }_{tr}\left(f\right)\right),\mathop{\mathrm{image}}$ the coefficient of reflection of G^TR of the tested reflector is determined using the formula $G^{tr}=G^{ret}\sqrt[3]{\left|A_3^{tr}\right|/\left|A_3^{ref}\right|}.\mathop{\mathrm{image}}$ The device for measurement of the reflection coefficient comprises a metering antenna, a reference flat reflector, a device for measurement of complex amplitude of the reflected signal, a microwave cable, a calculator. At the same time the antenna is made in the form of an axisymmetric parabolic mirror with a radiator in its top, and at the edge of the mirror there is a radio transparent fixator with a mechanism of alignment of the flat reflector position.;EFFECT: higher accuracy of measurement of reflection coefficient.;2 cl, 5 dwg