Low-Profile, Electrically Small, Huygens Source Antenna With Pattern-Reconfigurability That Covers the Entire Azimuthal Plane

A pattern-reconfigurable, low-profile, efficient, electrically small, near-field resonant parasitic (NFRP), Huygens source antenna is presented. The design incorporates both electric and magnetic NFRP elements. The electric ones are made reconfigurable by the inclusion of a set of p-i-n diodes. By arranging these electric and magnetic NFRP elements properly, a set of three Huygens sources are attained, each covering a 120° sector. Pattern reconfigurability is obtained by switching the diodes on or off; it encompasses the entire 360° azimuth range. A prototype was fabricated and tested. The numerical and experimental studies are in good agreement. The experimental results indicate that in each of its instantaneous states at <inline-formula> <tex-math notation="LaTeX">$f_{0} = 1.564$ </tex-math></inline-formula> GHz, the antenna provides uniform peak realized gains, front-to-back ratios, and radiation efficiencies, respectively, as high as 3.55 dBi, 17.5 dB, and 84.9%, even though it is electrically small: <inline-formula> <tex-math notation="LaTeX">$ka = 0.92$ </tex-math></inline-formula>, and low profile: <inline-formula> <tex-math notation="LaTeX">$0.05~\lambda _{{\mathbf {0}}}$ </tex-math></inline-formula>.