Method for determining one or more values of one or more physical parameters of a target volume and comprising the steps of: - positioning a field source at at least one first distance h 1, s from said target volume; - positioning a field receiver at at least one second distance h 1,f from said target volume; - for each couple of distances ( h 1, s, h 1, f), providing to said field source an incident signal a such that said field source sends incident electromagnetic waves to said target volume, some of said incident electromagnetic waves hitting afterwards said field receiver; - for each couple of distances ( h 1, s, h 1, f), acquiring a backscattered signal b mes from said field receiver, said backscattered signal b mes resulting from said incident signal a; - determining at least one measured signal S mes, each of said at least one measured signal S mes being determined for each couple of distances ( h 1, s, h 1,f) and being a function of said backscattered signal b mes; - representing said field source by N equivalent source elements, N being an integer greater than or equal to one; - representing said field receiver by M equivalent receiver elements, M being an integer greater than or equal to one; - providing antenna-characteristic reflection and transmission coefficients of said N source elements and said M receiver elements; - calculating at least one simulated signal S sim, each of said at least one simulated signal Ss im being calculated for each couple of distances ( h 1, s, h 1, f) by considering electromagnetic propagation phenomena taking place in said target volume subjected to incident electromagnetic waves; - determining said one or more values of said one or more physical parameters that minimize a function ø depending on said at least one measured signal S mes and said at least one simulated signal S sim; characterized in that said antenna-characteristic reflection and transmission coefficients include M specific global reflection coefficients R f,1 ( i = 1... M) for the M equivalent receiver elements, and in that when calculating the at least one simulated signal S sim, said receiver elements are considered as sources of electromagnetic waves to said target volume by the introduction of said M specific global reflection coefficients R f,i and MxM receiver-receiver functions G ij f i = 1... M; j = 1... M in feedback loops. - positioning a field source at at least one first distance h 1, s from said target volume; - positioning a field receiver at at least one second distance h 1,f from said target volume; - for each couple of distances ( h 1, s, h 1, f), providing to said field source an incident signal a such that said field source sends incident electromagnetic waves to said target volume, some of said incident electromagnetic waves hitting afterwards said field receiver; - for each couple of distances ( h 1, s, h 1, f), acquiring a backscattered signal b mes from said field receiver, said backscattered signal b mes resulting from said incident signal a; - determining at least one measured signal S mes, each of said at least one measured signal S mes being determined for each couple of distances ( h 1, s, h 1,f) and being a function of said backscattered signal b mes; - representing said field source by N equivalent source elements, N being an integer greater than or equal to one; - representing said field receiver by M equivalent receiver elements, M being an integer greater than or equal to one; - providing antenna-characteristic reflection and transmission coefficients of said N source elements and said M receiver elements; - calculating at least one simulated signal S sim, each of said at least one simulated signal Ss im being calculated for each couple of distances ( h 1, s, h 1, f) by considering electromagnetic propagation phenomena taking place in said target volume subjected to incident electromagnetic waves; - determining said one or more values of said one or more physical parameters that minimize a function ø depending on said at least one measured signal S mes and said at least one simulated signal S sim;