Wide band harmonic suppression based on Koch-shaped defected ground structure for a microstrip patch antenna

In this article, a wide band harmonic suppression microstrip patch antenna using the Koch-shaped defected ground structure (DGS) is presented. In order to realize the wide band harmonious suppression, the Koch-shaped defected ground structure (DGS) microstrip circuit is designed as the feed part of the proposed antenna. By inserting parallel slots, the antenna can be directly fed by the simple 50Ω microstrip transmission line. The proposed patch antenna operates at the center frequency of 2.5GHz and the spurious radiations up to 15GHz are properly suppressed. Simulated and measured results indicate that the Koch-shaped defected ground structure (DGS) is effective in suppressing spurious radiations. And the patch antenna considered here can be widely applied in active integrated communication systems.