A Compact Rat-Race Coupler with Harmonic Suppression for GSM Applications: Design and Implementation Using Artificial Neural Network

In this paper, a compact microstrip rat-race coupler at 950 MHz operating frequency is designed, simulated, and fabricated. New branches are proposed in design using high-/low- impedance open-ended resonators. the conventional coupler, there three long λ/4 3λ/4 branch, they occupy very large area. presented for use instead of an ultra-compact branch suggested branch. Additionally, artificial neural network (ANN) approach incorporated to improve performance resonators radial basis function (RBF) network. The structure has achieved reduction more than 82% compared with size structures. can suppress 2nd up 5th harmonic device.