Electrically Small, Low-Profile, Planar, Huygens Dipole Antenna With Quad-Polarization Diversity

An electrically small, low profile, planar, Huygens dipole antenna with four reconfigurable polarization states is presented. The design incorporates both electric and magnetic near-field resonant parasitic elements and a reconfigurable driven element. The four polarization states include two orthogonal linear polarized (LP) and two circular polarization (LHCP and RHCP) states. A 1.5 GHz prototype was fabricated (partially with 3-D additive manufacturing), assembled, and tested. The measured results, in good agreement with their simulated values, demonstrate that even with its simple configuration, electrically small size (ka = 0.944), and low-profile height (0.0449λ0), this reconfigurable Huygens antenna possesses stable broadside radiation performance in all of its four polarization states. The measured results demonstrate that in its x(y)-LP state, the peak realized gain, front-to-back ratio, and radiation efficiency values are, respectively, ~3.03 dBi (2.97 dBi), ~10.7 dB (9.9 dB), and ~68.2% (67.5%). For the LHCP (RHCP) states, they are, respectively, ~2.82 dBi (2.74 dBi), ~11.4 dB (12.5 dB), and ~67.1% (65.9%).