The multilayer folded couplers and their application

In this paper, three folded couplers and their application have been presented. The Wilkinson power divider, and 90° and 180° hybrids are folded for size reduction in the multilayered printed circuit media. The folded hybrid ring is employed as the transition between the microstrip line (MSL) and the parallel-strip line (PSL) for balanced circuit applications. The PSL has an inherent advantage of easy realization of balanced configuration, which is suitable for push-pull designs, especially for high power applications. The PSL makes the design of circuits more flexible than MSL because the lump components and solid state devices can be easily mounted in both series and shunt manners without any difficulties in fabrication. © 2006 Wiley Periodicals, Inc.