2010 Volume 7 Issue 3 Pages 153-158
A quasi fractal structure is introduced to build up a nondegenerate dual mode dual band bandpass filter. In the proposed filter a Koch fractal structure is applied to a microstrip patch resonator for miniaturization and dual band operation. The first band is specified by the first iteration of the fractal patch while the second band is determined with the second iteration. The most important feature is that the second band is independent of the first band and is simply tuned which is a challenge in dual band filters. A precise analysis of operation of the filter is presented. The measured results of the filter have good agreement with the full-wave simulated results.