Miniaturization of a Branch-Line Coupler Using Microstrip Cells

This article is devoted to miniaturization of the quadrature coupler device. A procedure for designing a miniature design based on replacing a section of a microstrip transmission line with a microstrip cell consisting of distributed capacitances and inductances having the same phase shift as the intercepted segment is described. Modeling of the proposed design and optimization of the parameters are carried out. The frequency characteristics illustrating the properties of the coupler are shown. A prototype with a center frequency of 1000 MHz was manufactured. The entire simulation process was performed using the AWR DE program. With the help of the vector network analyzer, the company R & S obtained experimental dependencies. The experimental results with a small error coincide with the results of the simulation. The area of the compact coupler turned out to be 74% less compared to the area of the device of traditional topology. It was noted that the reduction in the band of operating frequencies compared to the band of the traditional design decreased by only 3%.