Miniature constructions of microstrip couplers

Article is devoted to the research of a possibility to realize miniature constructions of microstrip couplers on the basis of simple replacement of a quarter-wave section of microstrip transmission line by a succession of high- and low-ohmic sections representing low-frequency filters. This way of dimensions reduction is compared to one of the simplest methods based on plain meander-like bend of microstrip transmission line. We have performed the simulation of presented coupler constructions with 1,000 MHz operation frequency and obtained their frequency characteristics comparable to traditional layouts within the given frequency range. FR4 with 4,4 dielectric permittivity and 1 mm thickness is taken as the material of the substrate. The miniaturization method featured by the author allowed to reduce the surface of two- and three-line couplers by 72,4% and 66,2% correspondingly in comparison with standard constructions.