Author(s)

Rohani Bakar^1*, Shumpei Fuse¹, Hiroyuki Arai¹, Yuki Inoue², Keizo Cho³

¹Department of Electrical and Computer Engineering, Yokohama National University, Yokohama, Japan.
²Research Laboratories, NTT DOCOMO INC, Yokosuka, Japan.
³Department of Electrical, Electronics and Computer Engineering, Chiba Institute of Technology, Chiba, Japan.

This paper presents a low profile dual polarized directional antenna composed of loop and dipole arrays mounted on a ground plane with each loops and dipoles being fed independently. Each loop antenna is paired with a reflector while each dipole antenna is paired with a director and a reflector. The proposed antenna is intended for an indoor base station (BS) with resonance frequency of 2.4 GHz and capable of producing four orthogonal directional pattern with downward elevation angle equals to 30°; and half power bandwidth (HPBW) less than 80°; in both vertical and horizontal polarization. The reflection characteristics of the loop and dipole arrays are less than -10 dB and the mutual coupling between the vertical and horizontal polarization elements is nearly less than -20 dB. In later progress, the dipole antenna was substituted with printed dipole antenna to achieve a better performance. Both the calculated and measured results demonstrated that the desired radiation patterns were achieved, and the measured results agreed well with the calculated ones. Consequently, a low profile antenna with a thickness of 0.16 λ (20 mm) having the expected radiation pattern is successfully designed.

Directional Antenna, Dual Polarization, Dipole Antenna, Loop Antenna, Reflector

Bakar, R. , Fuse, S. , Arai, H. , Inoue, Y. and Cho, K. (2015) A Low Profile Four-Way Directional Antenna with Dual Polarization. Journal of Electromagnetic Analysis and Applications, 7, 178-187. doi: 10.4236/jemaa.2015.75019.