Metamaterial millimeter wave directional coupler on silicon substrate

This paper presents the design and manufacturing of a metamaterial Composite Right/Left Handed (CRLH) directional coupler on silicon substrate in coplanar waveguide (CPW) configuration, with a frequency band between 26-28 GHz. The design makes use of 4 CRLH cells, cascaded and coupled two by two in order to obtain the directional coupler structure. The device was processed on a 500μm thick silicon substrate with a Au/Cr metallization with the purpose of easy integration in more complex millimeter wave integrated circuits. The measurement of working frequency, reflection loss and isolation of the coupler validates the calculated values of these parameters.