Electromagnetic (EM) characterization of engineered artificial materials such as bio- and nanomaterials is very important for several reasons. One of these reasons is future proliferation of 5G communication networks exposing urban population into the EM radiation of wide spectral range, therefore it is critically important to understand how new materials EM response can be utilized in electronic and communication devices and also ensure EM compatibility of biomaterials used inside human body. A new method to characterize permittivity and permeability of artificial materials using capacitively loaded aperture sensors is proposed and experimentally evaluated. The advantage of this new method over the existing techniques (free space, loaded waveguide, microstrip and coplanar waveguide resonators, coaxial probe, etc) is three-fold: i) resonance EM field enhancement inside the loaded aperture leads to very high sensitivity and therefore accuracy of EM parameters de-embedding; ii) only small thin samples of material-under test are required (with sample area substantially smaller than squared wavelength of radiation); iii) the method is easily scalable over the frequency and wavelength and based on relatively simple permittivity and permeability de-embedding procedure. This method can find application in EM materials characterization for existing and future electronic and communication devices.