Wideband, Electrically Small, Near-Field Resonant Parasitic Dipole Antenna with Stable Radiation Performance

A wideband, electrically small, and near-field resonant parasitic (NFRP) dipole antenna with stable radiation performance is presented. Inspired by recent metasurface antennas (MSAs), a coax-fed dipole antenna is loaded with a specially-engineered interdigitated NFRP element. It exhibits identical operating mechanisms to a developed electrically large slot-fed MSA, i.e., it has the similar adjacent fundamental mode and antiphase mode, and thus has a wide bandwidth property and uniform radiation patterns. The electrically small prototype was fabricated and measured. The measured results, in good agreement with their simulated values, demonstrate a wide 14.4% -10 dB impedance bandwidth along with a stable realized gain of 1.4 dBi over the entire band. Moreover, stable and uniform radiation patterns together with high radiation efficiency values were also measured. These performance characteristics make the reported electrically small antennas attractive for wideband and space-limited applications.