Theoretical and experimental study of compensated bridges in coplanar technology: Flexibility of the compensation method

This paper describes a systematic study of compensated bridges in coplanar technology. If bridges are necessary for filtering the parasitic coupled slot‐line mode excited by coplanar discontinuities, they modify the electrical characteristics associated with the fundamental even mode. Based on a low‐pass filter approach, a very simple technique is used to compensate for this parasitic effect. Here, emphasis is placed on the flexibility of this compensation technique, which allows us to reduce the technological constraints. Several solutions based on this approach are presented in the case of transmission lines, discontinuities such as tee junctions, and classical distributed bandpass filters. This study is valid for air bridges in classical coplanar technology, as well as for integrated dielectric bridges in multilayer coplanar technology. The concepts developed in this paper are illustrated theoretically and experimentally on multilayer devices over the 1–50 GHz frequency band.