Miniature branch-line coupler structure analysis

摘要

Due to a rapid development and sophistication of wireless devices that are used in the sphere of super high frequencies there appeared a new tendency, i.e. miniaturization of such devices. However, despite the decrease of sizes, such devices are to preserve operating specifications similar to those of standard structure devices. This article describes the problem of an accurate manufacturing of a compact coupler and decrease of working power that can be supplied to such device. The device can be miniaturized with the use of sequential high and low resistance sections that are equivalent to quarter-wave microstrip line and that are a low-pass filter (LPF). Numerical simulation of the coupler structure with the central frequency of 1,800 MHz was performed and frequency characteristics were obtained. Such miniaturization method allowed decreasing the coupler dimensions by 70% as compared to the standard structure.