A Low-Profile Magneto-Electric Dipole Antenna

A new low-profile magneto-electric dipole antenna composed of a horizontal planar dipole and a vertically oriented folded shorted patch antenna is presented. The antenna is simply excited by a coaxial feed without the need of an additional balun. A rectangular cavity-shaped reflector is introduced for enhancing the stability in radiation pattern over the operating frequencies. A parametric study is performed for providing practical design guidelines. A prototype with a thickness of 0.173λ was designed, fabricated and measured. Results show that an impedance bandwidth of 54.8% for SWR ≤ 1.5 from 1.88 to 3.3 GHz was achieved. Stable radiation pattern with low cross polarization, low back radiation and an antenna gain of 8.6 ± 0.8 dBi was found over the operating frequencies. In addition, the antenna is d.c. grounded, which satisfies the requirement of many outdoor antennas.