METHOD FOR MEASURING REFLECTION COEFFICIENT OF RADIO ABSORBING MATERIALS Russian patent published in 2017 - IPC G01R27/00 

FIELD: measuring equipment.

SUBSTANCE: method is proposed for measuring the reflection coefficient of the radio absorbing materials (RAM), including radiation of the radio absorbing material sample and the metal plate of the same size by the pulsed ultra-wideband signals, registration of the discrete signals corresponding to the signals from the radio absorbing material sample V_c and from the metal plate V_m, calculation of the amplitude signal spectra using the Fourier transformation and receiving the frequency characteristic of the reflection coefficient as a ratio of the amplitude spectra, and characterized in that the UWB signal is in the picosecond range, and the samples V_c and V_m are added with the zero counts to the length N before performing the Fourier transformation. Herewith N=2ⁿ≥100N₀, where N₀ is the original length of the samples, and then nuclear-aliasing of the samples V_c and V_m is performed in the Gaussian window with the width h. Herewith h is according to the maximum likelihood principle excluding the items one by one according to the formula , where V is the original sample, V_s - is the aliasing function, V/{i} - a sample with the excluded i-th count.

EFFECT: improving the measurement accuracy by decreasing the frequency step in the frequency coefficient characteristic of the RAM reflection and reducing the noise component of the measured pulse signals by the nuclear aliasing method, the relative error of determining the frequency characteristic of the reflection coefficient is reduced by 10-15 percent as compared to the prototype.

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