Antenna miniaturization without deteriorating performance is challenging because the performance is bounded by fundamental limits depending on the size of the antenna. Magneto-dielectric materials, however, have been reported as providing new possibilities for antenna miniaturization in many recent studies. In this paper, a novel material characterization method which is a cavity perturbation technique (CPT) with substrate integrated waveguide (SIW) cavity resonator is presented for extracting the properties of magneto-dielectric material. CPT formulas for extracting complex permittivity and complex permeability are explained and modification process using 3D EM simulation tool is discussed. Design and fabrication of SIW cavity resonators is presented. The frequency dependent properties of permittivity and permeability for synthesized magneto-dielectric material are extracted in the frequency range of 1-4 GHz. Microstrip patch antenna working at 1GHz on magneto-dielectric substrate has been designed and simulated in this paper.