Provided are wireless temperature sensors. A temperature sensor with a flexible, large-area printed thermistor can include an negative temperature coefficient (NTC) thermistor for temperature sensing, a control circuitry for electrically connecting with the NTC thermistor and obtaining the temperature sensed by the NTC thermistor, a power source for providing power supply to the NTC thermistor and the control circuitry, and a frame element for supporting the NTC thermistor, the control circuitry and the power source, where the frame element is at least partially thermally insulated to establish thermal equilibrium within the temperature sensor. The temperature sensor can sense the temperature in a fast and accurate way due to fast thermal equilibrium established within the sensor.