Suppression of harmonics in Wilkinson power divider using dual-band rejection by asymmetric DGS

TLDR

The paper proposes using an asymmetric spiral defected ground structure to suppress second and third harmonics in a Wilkinson power divider. The asymmetric spiral DGS is modeled as two cascaded parallel RLC resonators, providing signal rejection at two distinct resonance frequencies that suppress the second and third harmonics. Experimental results show the asymmetric DGS simultaneously suppresses the second and third harmonics by 18 dB and 15 dB, respectively, while reducing the quarter‑wave line length by 9.1 %.

Abstract

In this paper, we present an effective technique of second and third harmonic suppression for a Wilkinson power divider by using an asymmetric spiral defected ground structure (DGS). With the proposed technique, a single asymmetric DGS provides two different resonance frequencies because of the different sizes of spiral-shaped defects on the ground plane. The transfer function of the asymmetric DGS shows signal rejection characteristics at two different resonance frequencies and the characteristics of asymmetric DGS is modeled by two parallel RLC resonance circuits in cascade. With the insertion of asymmetric spiral DGS into a quarter-wave line of the Wilkinson power divider, the second and third harmonics are suppressed simultaneously. In experimental results, 18-dB suppression for the second harmonic and 15-dB suppression for the third harmonic, respectively, are achieved. Using asymmetric DGS, the size of a quarter-wave line is reduced by 9.1% compared to that of the conventional divider without a DGS.