Realization of Low-Profile and Reconfigurable Multilinear Polarization States for Cavity-Backed Magneto-Electric-Dipole Antenna

A low-profile multiple linear-polarization (multi-LP) reconfigurable cavity-backed magneto-electric (ME)-dipole antenna is developed in this letter. The magnetic-dipole is realized by a TM<inline-formula><tex-math notation="LaTeX">$_{020}$</tex-math></inline-formula>-mode slotted substrate-integrated cavity, and the electric-dipole is the printed microstrip dipole coupled above the slotted cavity. By introducing a rotationally symmetrical configuration of ME-dipoles with switchable feeding networks, we have realized the reconfigurable multi-LP states for the cavity-based ME-dipole antenna. As a benefit of the dipole-loaded slotted cavity configuration, the antenna profile is only <inline-formula><tex-math notation="LaTeX">$0.09\lambda _{0}$</tex-math></inline-formula>, which is much lower than conventional reconfigurable ME-dipole antennas. The developed antenna is capable of switching eight LP states at a <inline-formula><tex-math notation="LaTeX">$22.5^{\circ }$</tex-math></inline-formula> interval in real time by electronically controlling PIN diodes loaded on the slotted cavity. Measured results agree well with the simulated ones. At the center frequency of 5.04 GHz, a measured maximum gain of 4.46 dB is obtained for all polarization states. It is the first time to achieve simultaneous multi-LPs and low profile for ME-dipole antenna.