A multi-objective genetic algorithm approach applied to compact meander branch line couplers design for 5G-enabled IoT applications

This article describes a multi-objective genetic algorithm (MOGA)-based procedure used for the size reduction of a hybrid compact branch line coupler (BLC) intended for 5G applications that meet the requirements of IoT applications. Conventional λ/4 coupler transmission lines are replaced with meandering transmission lines to provide three different, simple and elegant designs that can operate at 3.5 GHz. A MOGA process is used to simultaneously balance the different design requirements and significantly reduce the bulky conventional structure size while maintaining high performance. To implement the optimization process, the proposed BLCs are designed using an interface between MATLAB software and a VBA script in the CST Studio simulator. The simulation results demonstrate a size reduction of 73.11%, 76.2% and 80%, respectively, for the three designs compared to conventional one. Then, for the demonstration of miniature BLCs operating at 3.5 GHz are fabricated on an FR-4 substrate. The measurements show good agreement with those obtained by simulation, making these BLCs a suitable choice for modern telecommunication systems requiring high compactness.