Capacitance Capacitive couplings Capacitive sensors Complementary split-ring resonator Coupling mechanism Dielectric materials Electric lines Electrically small resonator Inductive couplings Inductive sensors Microstrip lines Microstrip-line Microwave sensors Near fields Near-field sensors Optical resonators Polychlorinated biphenyls Ring gages Sensitivity enhancements Transmission-line capacitive coupling complementary split-ring resonators electrically small resonators inductive coupling microwave sensors near-field sensors sensitivity enhancement