Transponder

摘要

A transponder is disclosed to receive a wireless electromagnetic query signal and transmit a corresponding wireless electromagnetic response signal. The transponder comprises a first coil and at least one further coil that function as antennas to receive the wireless electromagnetic query signal and generate separate wired electrical incoming signals. An axis of the first coil and an axis of the at least one further coil are differently aligned in space, and each coil is associated with at least one means for limiting the voltage of the respective incoming signal. The separate wired electrical incoming signals are rectified and converted to current signals. The peak values of the current signals are detected and compared, such that a control signal is generated to identify one coil between the first coil and the at least one further coil that has a larger peak value of current.

主权项

1. A transponder, comprising: a first coil, coupled to receive a wireless electromagnetic query signal, the first coil acting as a first antenna and generating a first wired electrical incoming signal from the query signal; at least one further coil, coupled to receive the wireless electromagnetic query signal, the at least one further coil acting as a second antenna and generating a second wired electrical incoming signal from the query signal, an axis of the first coil and an axis of the at least one further coil having different spatial alignments, each of the first and at least one further coils being associated with at least one limiter means for limiting the voltages of the first and second wired electrical incoming signals; at least one full-wave rectifier, coupled to the first coil and the at least one further coil, the at least one full-wave rectifier generating a first rectified incoming signal and a second rectified incoming signal from the first and second wired electrical incoming signal, respectively; at least one current-controlled source of current, coupled to the at least one full-wave rectifier, the at least one current-controlled source of current generating a first current signal and a second current signal that correspond to the first and second rectified incoming signals, respectively; at least one current detector, coupled to the at least one current-controlled source of current, the at least one current detector detecting a first peak value of current signal and a second peak value of current signal that are associated with the peak values of the first and second current signals, respectively; a comparison arrangement, coupled to the at least one current detector, the comparison arrangement comparing the first and second peak value of current signals and generating a control signal, the control signal identifying one coil between the first coil and the at least one further coil that has a larger peak value of current.