Electrically small, low profile, broadside radiating LP and CP Huygens dipole antennas

Abstract

Electrically small Huygens dipole antennas are reported that are low profile, broadside radiating, have high radiation efficiencies, and are either linear (LP) or circularly (CP) polarized. The Huygens behavior, i.e., a high front-to-back ratio with a cardioid-like pattern, is realized by exciting two (LP) or two pairs (CP) of complementary electric and magnetic dipole radiators, simultaneously having the same amplitude and proper phase. These designs are achieved with near-field resonant parasitic (NFRP) Egyptian axe dipole (EAD) elements that act as the electric radiators and capacitively loaded loop (CLL) NFRP elements that act as the magnetic radiators. By efficiently combining the crossed EAD and CLL NFRP elements together with proper excitations by a single (LP) or a pair (CP) of driven dipole elements, the resulting electrically small antennas generate broadside Huygens radiation patterns. They have ka 0 ; exhibit good radiation performance with better than 4.5 dBi LP and 4.5 dBic CP peak realized gains; have > 20 dB front-to-back ratios; and have > 90% radiation efficiencies at their resonant frequencies. These antenna systems are quite suitable for a variety of compact narrow bandwidth applications including wireless power transfer (WPT), unmanned aerial vehicles (UAVs), and on- and off-body sensor networks.