Evolution of varactor-loaded frequency and polarization reconfigurable microstrip patches

This paper briefly describes different varactor-loaded multi-subpatch microstrip antenna solutions. Different solutions form kind of an evolutionary sequence, illustrating the process of attaining quite complex final antenna design, and describing main properties of individual solutions themselves. The final antenna represents completely frequency and polarization reconfigurable antenna, adjustable by means of varactor diodes, biased by DC voltages. The final design was fabricated and tested in several variations showing extensive frequency and polarization reconfigurability, while maintaining good impedance matching and radiation performances.