Evaluation and improvement of the performance of harmonic RADAR transponders

Efficiency of the harmonic radar transponder tag primarily depends on the details of its physical shape and the properties of the attached diode. Tag performance means to efficiently convert the incident radio wave signal into a transmitted harmonic signal that yields greater detection range. In this study, performance of wire-based tags are evaluated based on their resonant frequencies, absorption cross-sections, and radiation properties. During the evaluation of absorption cross-section, SPICE parameters of the diode are employed to accurately model the diodes. Tag architectural features including loop offset, wire diameter, and wire deformation are examined in terms of the tag's performance. Results show that an arm ratio of 2:1 is optimal, that small diameter wire is preferable, and that some deformation of the dipole may improve pattern coverage. The derived information is useful and expandable for the optimization of the many types of transponders.