A Novel Four-Port Phase Mode Antenna and Its Application in Multi-Polarization Wide-Angle Scanning Phased Array

In this paper, a novel four-port phase mode antenna (PMA) with multi-polarization beam scanning capability is proposed. By adjusting the phase difference between feeding ports, the four-port PMA can excite different phase modes allowing for multi-polarization beam scanning. It is observed that the even mode and odd mode, the basic modes of the PMA, correspond to the different characteristic modes in the antenna. Additionally, a detailed explanation of the variation law of phase modes is provided based on the characteristic mode theory. Simulated and measured results demonstrate that the proposed four-port PMA can achieve independent vertical polarization and horizontal polarization beam scanning in the
yoz
plane. By combining two orthogonal polarized beams, the antenna can achieve various other polarizations. Furthermore, its application is investigated in wide-angle scanning phased array. For the 1-D generalized array based on the four-port PMA, the measured results of vertical polarization, horizontal polarization, oblique +45° polarization and right circular polarization indicate that the maximum scanning angle of array can reach more than ±80° in the yoz plane, while maintain the cross-polarization level below -20 dB. Obviously, the four-port PMA offers more freedoms in beamforming, which provides a good prospect for the development of radar and wireless communication.