A Compact Magnetic Multipole Antenna for Wide 2-Dimensional Beamwidth

In this paper, a magnetic multipole antenna with a wide 2-dimensional (2-D) beam-width characteristic is proposed. The proposed antenna is configured by three magnetic dipole elements where multiple magnetic dipoles are defined as a single multipole antenna element. Although the radiation sources are composed by three magnetic elements, the overall size is very compact and less than a single patch antenna size at a same operation frequency. One magnetic dipole element has an excitation signal feed point and the other two magnetic dipole elements are placed beside the main radiation element. Then, magnetic currents on the two magnetic dipole elements are induced and magnetic fields are added. By configuring different sizes for each magnetic dipole elements, a resonance frequency can be controlled. Also, the multiple magnetic dipoles radiate wider beam pattern, results in a wide half power beam-width (HPBW) in both H-plane and E-plane over the multipole radiation element. The proposed magnetic multipole antenna with the radiation element size in 0.31λ x 0.31λ and the ground plane size in 1.1λ x 1.1λ was fabricated and verified at 5.8 GHz. The measured peak gain was about 6.34 dBi at 5.8 GHz and the 10-dB impedance bandwidth was about 240 MHz. Also, the radiation efficiency was about 93%.