For the disclosure, and preferably, a 2.45 GHz frequency band for communication and a 5.8 GHz energy transfer are considered. It is to be noted that for both communication and wireless energy transfer, any other adequate frequency band could be considered. The passive sensor has an antenna (13) and two impedance matching networks (7) and (8) that can be optimized for the desired frequencies, has one or more semiconductors (6) allowing low-power backscatter communication. The voltages controlling the semiconductors (12) are provided by the microcontroller (14) and this is fed continuously by the energy emitters. The passive sensor has a voltage multiplier (9) for converting the electromagnetic energy into electrical energy, followed by a voltage regulator (10) in order to maintain a controlled voltage level. The regulated voltage (11) powers the microcontroller in a continuous manner.

In order to increase the modulation order of the backscatter communication, the sensor may include one or more semiconductors (17) which are independently controlled (15) by the microcontroller. The sensor has an impedance matching network, voltage multiplier and voltage regulator (16).

Switching on and off of the semiconductors, at certain times, allows the reader to decode and thus read the data transmitted by the sensors. Applying different voltages in each of the semiconductors results in different types of modulations.

This disclosure finds applicability in scenarios where obtaining interior or exterior location of objects is desired. It can be used in agricultural environments to control soil moisture and can be used for access control such as in car parks. The sensor can be embedded in locations where replacing batteries can be difficult or impossible.