A New Fractal Microstrip Bandpass Filter Design Based on Dual-Mode Square Ring Resonator for Wireless Communication Systems

Ali, J.K.; Husain, N.N.

	A New Fractal Microstrip Bandpass Filter Design Based on Dual-Mode Square Ring Resonator for Wireless Communication Systems
Iraqi Journal of Applied Physics
Article 1, Volume 5, Issue 1, 2009, Pages 9-14
Authors
J.K. Ali; N.N. Husain
Abstract
A new fractal design scheme has been introduced to generate dual-mode microstrip bandpass filter designs with miniaturized sizes for wireless applications. The presented fractal scheme is based on the Koch pre-fractal geometry applied to the conventional dual-mode microstrip square ring resonator as an initiator in the fractal generation process. The space-filling property that the proposed structures possesses, was found to produce reduced size symmetrical structures corresponding to the successive iteration levels. In addition, self-similarity of the whole structure about its diagonal, at any iteration level, enables it to produce the two degenerate modes which can then be coupled using a proper perturbation technique. These filter designs are of sizes suitable for use in modern wireless communication systems. The performance of each of the generated bandpass filter structures up to the 2nd iteration has been analyzed using a method of moments (MoM) based software IE3D, which is widely adopted in microwave research and industry. Results show that these filters possess good transmission and return loss characteristics, besides the miniaturized sizes gained; meeting the design specifications of most of wireless communication systems.
Keywords
Microstrip filter; Koch fractal; filter miniaturization; dual; mode resonator

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