Time-Modulated Antenna Array With Dual-Circular Polarization

This letter presents a time-modulated antenna array (TMAA) with a dual-circular (left-hand and right-hand) polarization. The TMAA is composed of a single-pole four-throw radio frequency switch and four linearly polarized elements arranged accordingly to the sequential rotation technique. A periodic switching of the elements leads to generation of sideband components in the frequency domain. The right-hand circular polarization (RHCP) and the left-hand circular polarization (LHCP) are synthesized over the first negative sideband frequency and the first positive sideband frequency, respectively, in wide frequency band. The TMAA used in the receiving mode provides conversion of polarization diversity into frequency diversity, therefore enabling simultaneous reception and automatic separation of two electromagnetic waves, which have the same frequency, however, mutually orthogonal senses of polarization.