A Simple Single-Layered Continuous Frequency and Polarization-Reconfigurable Patch Antenna Array

This communication presents a design concept and realization of a patch antenna array with frequency and polarization reconfigurabilities. The frequency tunability is achieved using one short-circuited varactor diode per patch element. These tuning components also facilitate the generation of different polarizations by arranging the patches both horizontally and vertically. The 45° linear polarization (LP) is obtained by feeding all patches with the same phase, i.e., setting all varactor capacitance the same value. The circular polarization (CP) is obtained by slightly detuning the varactor capacitance such that the phase difference between the horizontal and vertical radiating elements is 90°. For validation, a 2 × 2 array has been fabricated and measured. The array prototype can operate with 45° LP, left-handed, or right-handed CP in a continuous tuning frequency range from 3.6 to 4 GHz (about 10%).