Single-Port Reconfigurable Magneto-Electric Dipole Antenna With Quad-Polarization Diversity

We propose a magneto-electric (ME) dipole antenna which is able to provide four states of polarization control, namely, the linear polarization (LP) in <inline-formula> <tex-math notation="LaTeX">$x$ </tex-math></inline-formula>-direction, LP in <inline-formula> <tex-math notation="LaTeX">$y$ </tex-math></inline-formula>-direction, left-hand circular polarization (CP), and right-hand CP. Under each of the two LP states, the reconfigurable ME dipole can be further tuned to work in two adjacent frequency ranges (i.e., a relatively higher band and a lower band). The uniqueness of this design arises from the fact that all the polarization and frequency agilities can be realized with a single port and without complicate feeding network, thus eliminating the insertion loss and considerably increased design complexity associated with a reconfigurable feeding network. Other advantages that make the proposed design attractive comparing with conventional reconfigurable microstrip antennas include the comparatively stable and high gain, nearly the same gain for both linear and CPs, symmetrical radiation pattern, and low back radiation level at the operating frequencies.