Method and system for wirelessly and passively measuring temperature and devices forming the system

A system for wirelessly and passively measuring temperature, comprising a wireless and passive temperature sensing device, an energy feedback device, and a receiving and processing device;

• wherein the energy feedback device comprises a first temperature compensation crystal oscillator and an RF power amplifier, and an RF signal from the first temperature compensation crystal oscillator is amplified by the RF power amplifier and is further transmit to the wireless and passive temperature sensing device;
• wherein the wireless and passive temperature sensing device comprises an RF receiving circuit, a storage capacitor, and a crystal oscillator circuit, the RF receiving circuit receiving the RF signal from the energy feedback device and storing energy of the RF signal into the storage capacitor;
• wherein after a voltage of the storage capacitor reaches a suitable level, the crystal oscillator circuit is activated to transmit an RF signal under a current temperature from the crystal oscillator circuit to the receiving and processing device;
• wherein the receiving and processing device comprises a second temperature compensation crystal oscillator, an RF receiving amplifier, and a signal processor, the RF receiving amplifier receives the RF signal under the current temperature from the wireless and passive temperature sensing device and outputs the RF signal from the wireless and passive temperature sensing device into the signal processor, and the signal processor calculates the current temperature according to an inherent frequency of the second temperature compensation crystal oscillator and the received RF signal under the current temperature.