Summary
International Symposium on Antennas and Propagation
2010
Session Number:3TA3
Session:
Number:3TA3-1
Beam Switched Antenna by Phase Difference Feed
Kenta ABE, Hiroyuki ARAI, Tsutomu MITSUI, Nobuyasu TAKEMURA,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
The securing of indoor communication quality is needed as cellular communications spreads. When the base-station antenna is set up indoors, the desired radiation pattern is different according to the installation location. In general, it is suitable to have monopole radiation pattern on the ceiling and uni-directional pattern on the wall side installation [1]. It is also required that the antenna is low profile and space-saving for the actual system requirements. There are many ways to implement beam switched antennas. In [2]; an array of parasitic elements and a reflector around the antenna are used. Whereas in [3]; two or more antennas with different directivity are combined and the excitation ports are switched. As the beam tilt dipole antenna in [2], it switches two or more parasitic elements around the excitation element. Polarization diversity antenna in [3] introduces beam switching by combining notch antenna and planar inverted-F antenna. Using parasitic elements in [2] and combining different shape antennas in [3] provides various switching patterns, however, the occupied space of antenna is expanded and may be complex in structure. In this paper, the antenna with two radiation patterns is proposed by switching the phase of excitation ports for the closely-located two planar F-shaped antennas. Resonance frequency is 2.7 GHz (λ = 111.1 mm), and the antenna size is 25 mm × 25 mm × 5 mm (0.225 λ × 0.225 λ × 0.045 λ). In section 2, the proposed antenna geometry and operation are explained, and the switch of the radiation pattern by the phase difference feed is also demonstrated. The section 3, we show the method to decrease the mutual coupling by using a neutralization technique for the closely placed elements. In section 4, we confirm the beam switching characteristics by the prototype antenna.