“…Different types of metamaterial structural units and surfaces have been widely proposed recently for various modes of sensors [1][2][3][4][5][6]. Near field microwave probes can confine evanescent fields to regions having dimensions much smaller than operating wavelength, and hence they are able to resolve sub-wavelength features and thereby provide a resolution much higher than the classical Abbe limit [7,8]. Earlier microwave near-field techniques mainly focused on a topology of microstrip line resonator terminated with a sharpened tip or a small loop and were reported to achieve a better resolution in dielectrics [9][10][11].…”