Very narrow band sensor antenna for accurate data reading

A purely radio-frequency wireless sensor capable of measuring physical parameters with a very low energy consumption is presented. By integrating a capacitive temperature sensor (a change in temperature is traduced by a change in a capacity value) to a very narrowband antenna, the antenna operating frequency band becomes controlled by the surrounding temperature that translates it, depending on its value. By making sure that there is a bijection between the surrounding temperature and the antenna operating band in the considered two ranges, there is no need to use any digital data to wirelessly transmit the information about the temperature. In this case, an important energy consumption reduction could be achieved since the whole wireless sensor would be composed of only a wideband pulse generator and the sensor antenna that selects the band to transmit based on the temperature. To demonstrate the concept, a prototype has been built by modelling the capacitive sensor with a varying capacitance. Both simulated and measured results show a reasonably good agreement which validates the concept.