Quasi-Fractal Periodic Defected Ground Structure for CPW Lines

Conference: GeMiC 2009 - German Microwave Conference
03/16/2009 - 03/18/2009 at München, Germany

Proceedings: GeMiC 2009

Pages: 3Language: englishTyp: PDF

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Batmanov, Anatoliy; Burte, Edmund (Chair of Semiconductor Technology, University of Magdeburg, Universitätsplatz 2, 39104 Magdeburg, Germany)
Boutejdar, Ahmed; Omar, Abbas (Chair of Microwave and Communication Engineering, University of Magdeburg, Universitätsplatz 2, 39104 Magdeburg, Germany)

A two-dimensional (2D) quasi-fractal periodic defected ground structure (PDGS) for coplanar waveguide is proposed and compared with a standard dumbbell PDGS. It is based on the repetition of the unit-cell in a simplified and symmetrical way. The equivalent circuit model of the defected ground is a simple parallel resonance circuit. The EM simulation and the equivalent circuit model suggest that the capacitance is almost constant while the inductance varies linearly relative to the number of cells. But the capacitance of the quasi-fractal PDGS is higher than for the standard PDGS with the same dimensions. It leads to a shift of the resonant frequency to a low frequency range and to the decrease of the bandwidth. The center frequency varies from 10 GHz down to 4.4 GHz with more than -20 dB rejection in the stopband when the number of cells increases from 1 to 5-cells. Measurements are in good agreement with theoretical predictions.