Abstract:
Results are presented fora wideband printed magneto-electric dipole
antenna. The printed electric dipole and reflector are separated by
an air-gap and is fed with a coaxial transmission line and a printed
proximity coupled T-shaped feeding strip. The slot between the electric
dipole halves forms the magnetic dipole radiating aperture. This
feeding mechanism allows for good impedance matching at adjacent
resonances of the electric and magnetic dipoles to achieve wideband
operation. The two printed electric dipole halves are DC shorted to the
reflector. The results show that this antenna can operate over a wide
bandwidth with good gain, stable unidirectional radiation patterns
and low cross polarization. The effect of the air-gap height and the
relative permittivity of the substrate on which the dipole is printed are
investigated. Results show that an optimum air-gap height for a specific
substrate permittivity can be determined that will result in a gain with
a small variation over the entire impedance bandwidth of the antenna.
Simulated as well as measured results are presented for a prototype
antenna with a small gain variation and overall dimensions of 1.33λ0
× 1.33λ0 × 0.19λ0. A measured impedance bandwidth of 54% with an
average gain of 9.2 dBi is achieved.
