Compact branch-line coupler using composite right/left-handed transmission lines with novel CSSRR

In this paper, a novel compact-size branch-line coupler using composite right/left-handed transmission lines is proposed. In order to obtain miniaturization, composite right/left-handed transmission lines with novel complementary split single ring resonators which are realized by loading a pair of meander-shaped-slots in the split of the ring are designed. This novel coupler occupies only 22.8% of the area of the conventional approach at 0.7 GHz. The proposed coupler can be implemented by using the standard printed-circuit-board etching processes without any implementation of lumped elements and via-holes, making it very useful for wireless communication systems.