A building-block design scheme for planar transmission-line transitions

A building-block design scheme for transitions between planar transmission lines is proposed. Two building blocks, including CPW-to-microstrip and microstrip-to-CPS, are first designed. Then, both building blocks are cascaded to form CPW-to-CPS transitions. In addition, each building block is also the combination of sub-building blocks which are responsible for impedance or field matching in the transmission-line discontinuities. The detailed concept of the design scheme is demonstrated with a series of transitions manufactured on printed circuit boards in the X-band. The proposed transitions are fabricated in back-to-back configuration and measured using a vector network analyser. The measurement results show good agreement with simulation.