Optimization of dual-polarized bistatic specular scatterometer for studying microwave scattering response and vegetation growth parameters retrieval of paddy crop using a machine learning algorithm

•Bi-spec scatterometer measurement system was indigenously designed at X and C bands.•The experiment was performed in the incidence angular range of 20° to 60°.•The insight of microwave scattering through paddy was analyzed using the experiment.•Optimization was done by correlation analysis between σ0 and crop growth parameters.•The multi-kernel SVR model was developed for crop growth parameters retrieval.•The SVR model using radial kernel showed best result for LAI, FBm and VWC at C-band.•For PH estimation, the results were good at X-band using bi-spec scatterometer data.