Broadband Transponder Based on Frequency-Reconfigurable Cluster Antenna and Phased Modulators

This letter presents a new concept of broadband transponder based on frequency-reconfigurable cluster antenna and phase-variable modulators. The transponder in this concept has multiport antenna, whose elements have strong mutual coupling between them. The technique presented in this concept takes advantage of the coupling between the antenna elements instead of avoiding it. By properly weighting the phases of the modulated signals in each port, the backscattered received power can be maximized. The weighting is done differently for different sets of frequencies to achieve instantaneous bandwidth over the frequency band of interest.