A new class of passive subharmonic transponders

The basic structure and principles of operation of the 1-port passive subharmonic transponder (PST) as a remotely interrogatable electronic label employing near field coupling are outlined. It is shown that the synchronously interrupted resonance process can be used to generate an information-bearing reply code while simultaneously minimising the electromagnetic loss in a PST interrogation system. A model of the power-transfer process, incorporating directly measurable or readily available parameters, is presented. The analysis is facilitated by harmonic analysis of the unmodulated and modulated waveforms and the definition of fundamental quality factors appropriate to the interrupted resonance process.