Abstract: A sensor module may be formed including a core of ferromagnetic material associated with a wire coil forming a passive inductor resonant circuit, which may be used in temperature sensor modules and pressure sensor modules suitable for use in high temperature, high pressure, and corrosive environments. The passive inductor resonant circuits of the sensors may be tuned such that its resonant frequency is in a bounded frequency band interrogable with an electromagnetic energy signal having a frequency of less than or equal to about 10 MHz. Such sensors may be disposed in series in a sensor array, interrogable with an interrogation module, where the interrogation module may demultiplex, the frequencies of the multiple sensors to determine the environmental conditions sensed by the individual sensors.