Bandwidth-Enhanced, Electrically Small, Planar, Endfire-Radiating Huygens Dipole Antenna

Abstract

A bandwidth-enhanced, electrically small, planar, endfire-radiating Huygens dipole antenna (HDA) is presented. The near-field resonant parasitic (NFRP) grid-shaped dipole and two concentric interdigitated capacitor (IDC) loaded loops enable broad electric and magnetic dipole responses, respectively. Benefiting from the additional capacitance introduced by the dual-loop design, the magnetic dipole response is achieved at a lower frequency. The consequent balanced resonant responses of the electric and magnetic NFRP elements yield a wideband and electrically small HDA with endfire-radiating performance characteristics. The fabricated prototype exhibited measured results that closely agree with their simulated values. Being an electrically small, <italic>ka</italic> &#x003D; 0.91, system, it had an 8.79&#x0025; fractional bandwidth and a 4.7 dBi peak realized gain. Furthermore, the antenna achieved unidirectional radiation patterns and maintained high radiation efficiency (RE), RE &gt; 81&#x0025;, within its entire operational bandwidth.