The characterization of the relative permittivity ({varepsilon} {mathbf{r}}) in the RF and microwave bands is essential for numerous applications, such as the design of microstrip antennas and microwave circuits. Thus, the characterization of material properties in real life applications (liquids, soils, water concentration, etc.) is extremely important because it assigns parameters not easily to typical measurement devices. In this work, a small prototype for characterization of the dielectric constant is presented using a resonator designed with microstrip transmission line analysis for a microwave range of frequencies. The design is validated using a commercial simulator and measurement results.