This paper presents the technique and associated miniature RF biosensor dedicated to the microwave dielectric spectroscopy of carbohydrates in aqueous solution. Small amounts of liquid in the range of microliter are required. This sensor includes an area for electromagnetic field analysis that operates in the near field, while a microfluidic channel allows precisely bringing and locating the liquid solution to be studied on the sensing zone. Different carbohydrates were measured from 40 MHz to 40 GHz with relevant concentrations for biologists and chemists. Derived from the extracted complex relative permittivity of the examined liquids, this paper shows that each biomolecules type exhibits a specific dielectric signature, which allows their identification and quantification.