A method includes sending, by a reader, a radio frequency (RF) signal to a wireless sensor that includes an antenna having a tail section and a head section. The tail section is for placement in an RF limited area for sensing moisture in a first location of a vehicle under test and wherein the head section is for placement in a non-RF limited area. The method further includes receiving, by the reader, an RF response to the RF signal from the wireless sensor. The first RF response includes an indication of adjustment of one or more RF characteristics of the wireless sensor, which corresponds to a variance of the one or more RF characteristics from a desired value, which, in turn, corresponds to a level of moisture at the first location. The method further includes outputting, by the reader, a message regarding the level of moisture at the first location.

A method includes sending, by a reader, a radio frequency (RF) signal to a wireless sensor that includes an antenna having a tail section and a head section. The tail section is for placement in an RF limited area for sensing moisture in a first location of a vehicle under test and wherein the head section is for placement in a non-RF limited area. The method further includes receiving, by the reader, an RF response to the RF signal from the wireless sensor. The first RF response includes an indication of adjustment of one or more RF characteristics of the wireless sensor, which corresponds to a variance of the one or more RF characteristics from a desired value, which, in turn, corresponds to a level of moisture at the first location. The method further includes outputting, by the reader, a message regarding the level of moisture at the first location.

Methods and apparatuses for use in tuning reactance are described. Open loop and closed loop control for tuning of reactances are also described. Tunable inductors and/or tunable capacitors may be used in filters, resonant circuits, matching networks, and phase shifters. Ability to control inductance and/or capacitance in a circuit leads to flexibility in operation of the circuit, since the circuit may be tuned to operate under a range of different operating frequencies.

Methods and apparatuses for use in tuning reactance are described. Open loop and closed loop control for tuning of reactances are also described. Tunable inductors and/or tunable capacitors may be used in filters, resonant circuits, matching networks, and phase shifters. Ability to control inductance and/or capacitance in a circuit leads to flexibility in operation of the circuit, since the circuit may be tuned to operate under a range of different operating frequencies.

A method includes transmitting, by a radio frequency identification (RFID) reader, a series of RF signals to a plurality of RF receiver circuits in a time sequence. The first RF signal commands the plurality of RF receiver circuits to remain silent when received signal strength of the first RF signal corresponds to a power level greater than a first power level. The method further includes receiving one or more sets of responses from one or more sets of RF receiver circuits of the plurality of RF receiver circuits in response to the series of RF signals. The method further includes determining an area of interest based on the one or more sets of responses, determining a set of power levels corresponding to the area of interest, and transmitting a second series of RF signals to the plurality of RF receiver circuits in a second time sequence.

A method includes transmitting, by a radio frequency identification (RFID) reader, a series of RF signals to a plurality of RF receiver circuits in a time sequence. The first RF signal commands the plurality of RF receiver circuits to remain silent when received signal strength of the first RF signal corresponds to a power level greater than a first power level. The method further includes receiving one or more sets of responses from one or more sets of RF receiver circuits of the plurality of RF receiver circuits in response to the series of RF signals. The method further includes determining an area of interest based on the one or more sets of responses, determining a set of power levels corresponding to the area of interest, and transmitting a second series of RF signals to the plurality of RF receiver circuits in a second time sequence.

According to an aspect, a tank circuit in an integrated circuit comprising a plurality of metal strips forming a first part of a closed contour enclosing a first area, a set of split sections forming a second part and geometrically aligned with the closed contour, and a plurality of capacitors coupled between the split sections to form the tank circuit, wherein a first flux linkage due a current flowing in the set of split sections pass through the first area in the same direction as that of a second flux linkage due to the current flowing in the plurality of metal strips, and the set of split sections and the plurality of metal strips together forming an inductance coil.

A tunable inductor arrangeable on a chip or substrate comprises a first winding part connected at one end to a first input of the tunable inductor arrangement, a second winding part connected at one end to the other end of the first winding part, a third winding part connected at one end to a second input of the tunable inductor arrangement, a fourth winding part connected at one end to the other end of the third winding part, and a switch arrangement arranged. The switch arrangement tunes the tunable inductor by selectively connecting the first and fourth winding parts in parallel and the second and third winding parts in parallel, with the parallel couplings in series between the first and second inputs, or connecting the first, second, fourth and third winding parts in series between the first and second inputs. Corresponding transceivers, communication devices, methods and computer programs are disclosed.

A tunable inductor arrangeable on a chip or substrate comprises a first winding part connected at one end to a first input of the tunable inductor arrangement, a second winding part connected at one end to the other end of the first winding part, a third winding part connected at one end to a second input of the tunable inductor arrangement, a fourth winding part connected at one end to the other end of the third winding part, and a switch arrangement arranged. The switch arrangement tunes the tunable inductor by selectively connecting the first and fourth winding parts in parallel and the second and third winding parts in parallel, with the parallel couplings in series between the first and second inputs, or connecting the first, second, fourth and third winding parts in series between the first and second inputs. Corresponding transceivers, communication devices, methods and computer programs are disclosed.

A method includes receiving, by a radio frequency identification (RFID) tag, a radio frequency (RF) signal from an RFID reader. When the RF signal includes a command, the method further includes interpreting, by the RFID tag, the command to determine a field strength shell of interest. When the RFID tag is in the field strength shell of interest, the method further includes further interpreting, by the RFID tag, the command to determine a type of request, and providing, by the RFID tag, a response regarding the type of request to include one or more of a matched impedance value generated in response to the RF signal, a field strength reference current generated in response to the RF signal, and a digital value representative of an environmental condition.