Abstract: A method for detecting an object to be charged, by a charging device, including a transmitting coil and a microcontroller which are suitable for charging a portable item of user equipment at an operating frequency. The method including the following steps: transmitting a predetermined number of voltage pulses at the terminals of the transmitting coil, at a parasitic resonant frequency, contained in a window of values, the resonant frequency being different and distinct from the operating frequency; measuring the voltage at the terminals of the transmitting coil; comparing a frequency of the voltage thus measured and the window of values; if the frequency of the voltage is contained in the window of values, then detecting a portable item of user equipment to be charged.

Abstract: A radio-frequency identification tag that includes a ground plane made of an electrically conductive material, and an actuator made of a transducer material adapted to convert a variation of a physical quantity into a mechanical displacement of the ground plane between first and second positions when the physical quantity crosses a predetermined threshold in order to indicate this event to the reader. The transducer material is a thermal shape-memory material or a magnetostrictive material or a magnetic shape-memory material. The transducer material is also an electrically conductive material. The ground plane and the actuator are both formed by a single strip made of the transducer material and a mobile portion of which moves relative to an antenna between the first and second positions when the physical variable crosses the predetermined threshold.

Abstract: A radio tag capable of indicating to a reader, via a wireless link, that a variation in energy has crossed a predetermined threshold, this variation in energy being chosen from the group made up of a variation in the temperature of the radio tag and a variation in the magnetic field in which the radio tag is immersed. This radio tag includes transducer material chosen from a group made up of a thermal shape-memory material, a magnetostrictive material and a magnetic shape-memory material. This transducer material is deposited and affixed without any degree of freedom onto a substrate or an antenna of the radio tag to form, with the substrate or the antenna, a multilayer structure which flexurally deforms the antenna between a bent conformation and a less bent conformation when the energy variation crosses the predetermined threshold.

Abstract: The radio-frequency identification tag comprises: a ground plane made of an electrically conductive material, and an actuator made of a transducer material adapted to convert a variation of a physical quantity into a mechanical displacement of the ground plane between first and second positions when the physical quantity crosses a predetermined threshold in order to indicate this event to the reader, the transducer material being selected from a group consisting of a thermal shape-memory material, a magnetostrictive material and a magnetic shape-memory material. The transducer material is also an electrically conductive material. The ground plane and the actuator are both formed by a single strip made of this transducer material and a mobile portion of which moves relative to an antenna between the first and second positions when the physical variable crosses the predetermined threshold.

Abstract: A radio tag capable of indicating to a reader, via a wireless link, that a variation in energy has crossed a predetermined threshold, this variation in energy being chosen from the group made up of a variation in the temperature of the radio tag and a variation in the magnetic field in which the radio tag is immersed. This radio tag includes transducer material chosen from a group made up of a thermal shape-memory material, a magnetostrictive material and a magnetic shape-memory material. This transducer material is deposited and affixed without any degree of freedom onto a substrate or an antenna of the radio tag to form, with the substrate or the antenna, a multilayer structure which flexurally deforms the antenna between a bent conformation and a less bent conformation when the energy variation crosses the predetermined threshold.