The objective of this work is to find a method to distinguish different types of substances with high dielectric constant and high losses, such as is the case of biological tissues, to study the detection of tumors with technologies that enable the accurate identification of the areas to be removed, reducing the loss of healthy tissue. For this a microwave transmission-based sample analysis system has been designed. The biological sample is enclosed in a nylon box whose dielectric constant is much smaller than that of the samples under study. The working frequency is 35 GHz because this frequency maintains a good compromise between the dimensions of the waveguide and the depth of penetration in samples. A study analyzing the system's sensitivity to different biological samples has been done. Then it was verified that the system can distinguish the different separation profiles in a complex sample, yielding very promising results.