Compact Marchand balun circuit for UWB application
This article presents the development of a miniaturized differential coupler for UWB application using the Marchand balun circuit in multilayer technology. The new technique employs double layer substrate where on the bottom layer the two ?/4 short-circuited stubs with balanced outputs are developed and on the top layer the ?/2 open-circuited stub for unbalanced input is etched. These three transmission lines of the Marchand balun circuit are capacitively coupled using overlapping microstrip lines. To demonstrate this technique, a Marchand balun circuit using multilayer technology is designed, simulated, fabricated and measured. The circuit size is about 2.8mm3.7mm0.63mm excluding the feeding ports. The results from the simulation and measurement show good agreement.
marchand balun circuit balun circuit uwb application multilayer technology double layer substrate