A Wideband Cavity-Backed Elliptical Printed Dipole Antenna With Enhanced Radiation Patterns

A new wideband unidirectional cavity-backed elliptical printed dipole antenna with enhanced radiation patterns is proposed. The cavity utilized in the proposed antenna is a simple cylindrical cavity, which can generate broadside radiation patterns. An elliptical printed dipole director is placed in front of the elliptical printed dipole antenna for improving the radiation patterns in the upper frequency band. The antenna is fed by an SMA connector through a step-tapered balun accomplishing a transition from a microstrip line to a parallel stripline. The antenna is fabricated and measured. Results show that the antenna achieves an impedance bandwidth of 129.7% for VSWR ≤ 2.0 from 1.55 to 7.27 GHz. Stable unidirectional radiation patterns with an antenna gain of 8.04-13.27 dBi, low back radiation, and low cross polarization are found over the operating frequencies.