models used in soil moisture measurement using microwaves

hello everyone,
am looking for information about the models which are used for soil moisture measurement using microwaves if you have it or you have a site which can enable me get it i will highly appreciate if you pass it to me. these are mathematical models models used to calculate soil moisture from backscatter coefficient obtained from measurement using a scatterometer.

what do you mean by models .. do you mean to say modules? or are you lookin for some circuits ? what do you exactly want .