Multi-layer quadrature hybrid coupler design composed of multiple circular sectors

A hybrid coupler design composed of multiple circular sectors is presented. It is designed to cover wireless local-area network bands at 2.4, 5.25 and 5.8 GHz, ultra-wideband at 3.1 4.8 GHz, digital multimedia broadcasting at 2.6 GHz and WiMax at 3.5 GHz. The coupler achieves an amplitude imbalance of 1 dB and a phase error of 5 at the outputs within the design frequency range. The developed coupler was compared with other existing designs in literature. It demonstrated advantages in terms of wide operating bandwidth as well as small physical size.