2.1.1. Resonant Perturbation Method

In this method, the material to be measured was placed inside the cavity in an aperture and its dielectric properties were derived from the changes inside the cavity, by using conversion equations [31,32]. The changes in the cavity's resonant frequency and quality factor were caused by the insertion of the sample. This technique has high accuracy due to the control of the cavity's specifications and its initial conditions. As an initial step, in order to design the microstrip patch antenna, the dielectric properties of the four di fferent fabrics considered in this study were calculated at ambient RH and temperature. For this purpose, a material characterization split cylinder (85072A, Keysight Technologies, Reading, UK), working at 10 GHz, and a material characterization SW (N1500A-003 MMS 2015, Keysight Technologies, Reading, UK) for data conversion were used.
