A New Ultra-wideband Microstrip-to-CPS Transition

A novel ultra-wideband microstrip-to-CPS (coplanar stripline) transition has been developed. The transition is designed to provide the field and impedance matching between adjacent transmission lines. The proposed design is applicable to substrates with any dielectric constant. The transition provides the balun role as well as the impedance transformation. The fabricated transition in back-to-back configuration provides the insertion loss less than 1 dB per transition and the return loss better than 10 dB for frequencies from 5.39 GHz to over 40 GHz. In addition, a simulation study indicates that this transition can possess a 3 dB bandwidth of ~ 100 GHz.