Summary
International Symposium on Antennas and Propagation
2008
Session Number:3C25
Session:
Number:3C25-1
A Compact Dual-band Printed Dipole Antenna Based on Fractal Feature in ISM Band
Sarawuth Chaimool, Prayoot Akkaraekthalin,
pp.-
Publication Date:2008/10/27
Online ISSN:2188-5079
Summary:
Wireless communication systems now operate in two or more frequency bands, requiring dual- or multiband operation of narrowband antennas. In such cases, an antenna operates at two frequencies and can be used in several applications such as GSM-900, 1800, and IMT-2000. Dual-band antennas are not used only in mobile communications; in fact, they are widely used for dual industry, scientific and medical (ISM) band applications [1]. Various kinds of dual-band antennas have been found in the literatures, such as printed slot antennas [2], PIFA [3], the monopole [4], and others. Unlike dipole antenna, those antennas could not provide uniform omni-directional coverage, but they are suitable for low profile installation. As far as compact dipole antennas are concerned, it is mandatory to develop miniaturized radiators able to guarantee a good efficiency and reliability. In such a field, fractal antennas seem to be good candidates for achieving reduced dimensions keeping suitable radiation properties. This paper proposes a new dual-band printed dipole antenna based on fractal feature whose radiation pattern in the horizontal plane is omni-directional in both the 433 MHz and 900 MHz ISM bands. This technique has been imposed on fractal space-filling dipole antenna that is FASS (spaceFilling, self-Avoiding, Simply, and self-Similar) curve antenna. By properly choosing the dimension of a coupled slot on a dipole antenna, dualband and tunable impedance bandwidth characteristics for both 433 MHz and 900 MHz applications can be achieved. The proposed antenna satisfies the 10 dB return loss characteristics from 425 to 441 MHz (3.6%) for ISM-900 and 840 to 1200 MHz (20%) for ISM-900 applications, respectively.