RF based soil urea analysis using multivariate system

Abstract

The paper describes a novel approach for estimation of soil urea content using Radio Frequency signals. The frequency response of urea is obtained by using Radio Frequency signals. The experimental setup consists of a shielded cell, designed to obtain the frequency response of urea solution. The RF responses of urea with different concentrations in the range of 10MHz - 4.4GHz are obtained using a signal generator and a spectrum analyzer. The experimental results show that at certain frequencies, the response of urea to RF changes in accordance with the changes in the concentration of urea and at other frequencies, it has a flat response. Since the response of urea to RF changes in accordance to the concentration of urea, these results can be used for the prediction of unknown concentration of urea based on a multivariate system. The calibration set for the PLSR model is generated by taking different concentrations of urea. To predict the unknown urea concentration, PLSR model uses the calibration set for regression.