A passive sensor network constituted by a reader (5), wireless energy emitters (2), and fully passive sensors (1) is described. The passive sensors allow continuously the data collection and transfer thereof whenever requested by the reader, via backscatter at a frequency (4), and in parallel the reception of energy from the transmitters (3). Each sensor integrates an antenna, two impedance matching networks, a semiconductor, a microcontroller and one or more sensors that do not require the use of their own power supply or batteries. The reader (remote unit) initiates the communication process. This communication is achieved by sending radio frequency commands recognized by the passive sensors. These sensors, upon receiving the commands from the reader, initiate the back transmission of data according to the received command. The power transmitters are used to allow continuous power supply of the passive sensors.