A bio sensor using electromagnetic waves according to an embodiment may comprise a resonator assembly, a power supply unit, and a processor. The resonator assembly may include at least one feeding line which is disposed along the outer edge of a feeding area and can feed electric power to the feeding area, and a pattern wire which is disposed along a pattern in the feeding area and can receive electric power from the feeding line through capacitive coupling. The power supply unit may supply electric power to the resonator assembly. While a frequency of the electric power is swept, the processor may acquire a parameter which is biometric data corresponding to a concentration of a target analyte existing around the resonator assembly and is related to a resonant frequency of the resonator assembly.