Mirrored Coupling Structures for Microwave Signal Splitting and Combining

This paper presents a method of creating multi-port couplers by mirroring conventional coupler structures, such as 90° hybrids, Saleh power dividers, and Wilkinson couplers. These created structures maintain some very useful features of the original structures, for example, stable phase shifting between ports, equal power dividing, and port isolation. Theoretical analysis method of these structures is discussed for S-parameter derivation. Example structures: a four-way coupler by mirroring 90° hybrid couplers, and an eight-way coupler by mirroring Saleh power-dividing couplers were built and tested according to the method discussed. A good match was found between theoretical analysis and measurements.